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  • Corn Oil-Derived Poly (Urethane-Glutaric-Esteramide)/Fumed Silica Nanocomposite Coatings for Anticorrosive Applications
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-29
    Manawwer Alam, Naser M. Alandis, Naushad Ahmad, Eram Sharmin, Mukhtar Ahmed

    Abstract Poly (urethane-glutaric-esteramide) (PUGEA) was synthesized using corn oil and glutaric acid and further treated with toluene-2, 4-diisocyanate. Fumed silica with 1, 2, and 3 weight percentage was included in the synthesized PUGEA resin to obtain PUGEA-1, PUGEA-2 and PUGEA-3 nanocomposite resins, respectively. The chemical structure of glutaric polyesteramide and PUGEA was characterized by Fourier-transform infrared spectroscopy and nuclear magnetic resonance (1H and 13C NMR). The morphology, hydrophobicity and thermal stability of the PUGEA nanocomposites were investigated by using scanning electron microscopy and energy-dispersive X-ray spectroscopy, by measuring contact angle and by thermogravimetric analysis (TGA). Afterward, the PUGEA/fumed silica nanocomposite coatings were applied on mild steel and dried at room temperature, and they were physico-mechanically characterized by measuring their scratch and pencil hardness, bending, impact resistance and cross-hatch adhesion. The anti-corrosion effectiveness of PUGEA-2 was investigated by electrochemical impedance spectroscopy immersing it for 42 days in a 3.5 wt% NaCl aqueous solution. Finally, TGA reveals that the PUGEA-3 nanocomposite coating can be safely used up to 275 °C.

    更新日期:2020-02-13
  • Novel Starch/Chitosan/Aloe Vera Composites as Promising Biopackaging Materials
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-30
    Dagmara Bajer, Katarzyna Janczak, Krzysztof Bajer

    Abstract Edible films based on potato starch, chitosan and Aloe vera gel (AV) as modifiers were evaluated towards their potential application in food or cosmetics industry. The films, with different AV gel concentration were prepared by casting method. The influence of UV radiation on samples chemical structure was analyzed. The surface morphology was observed with AFM method. The chemical structure and molecular arrangement of mixture components were analyzed with ATR–FTIR spectroscopy and X-ray diffraction. Hydrogen bond interactions among the film components, conformational rearrangements as well as changes in crystallinity degree were confirmed. A study of thermal resistance showed the delay of degradation observed together with an increase AV gel amount and after UV-irradiation. The hydrophilic character of the samples was proved. Water solubility slightly depends on the AV concentration in films, and it decrease after UV-irradiation. All the samples with AV gain the increase resistance to microbial action.

    更新日期:2020-02-13
  • Effects of Various Methods of Chemical Modification of Lignocellulose Hazelnut Shell Waste on a Newly Synthesized Bio-based Epoxy Composite
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-12
    Suheyla Kocaman, Gulnare Ahmetli

    Abstract In this study, a novel bio-based epoxy resin (ESA) with curable double bonds was synthesized by esterification reaction between sebacic acid (SAc) and epichlorohydrin (ECH). Its chemical structure was confirmed by FT-IR and 1H NMR. Untreated, alkali treated, acrylic acid (AcA)- and acetic anhydride (AA) modified hazelnut shell waste (HSh) were used as inexpensive reinforcing materials in the ESA matrix system. The composites were prepared with HSh in varied per cent values (10–50 wt%) using the casting technique. The effects of chemical modification and amount of reinforcement materials on the properties of the composites were investigated. The composites were characterized using mechanical tests, as well as SEM, XRD, TGA, and contact angle measurement. The morphological results indicate an improvement in adhesion between the HSh fillers and ESA matrix upon chemical treatments. The modified HShs reinforced composites showed an increase of 7.7–46.2% in elongation at break when compared to the untreated HSh reinforced composite at more appropriate 20 wt% of filler. Also, tensile strengths of all chemically modified HSh composites are higher than that obtained with neat ESA and untreated HSh composites. It was observed that 20 wt% AA-modified HSh composite exhibited higher tensile strength (66 MPa) and elasticity modulus E (6.72 GPa) values. The TGA analysis showed that the HShs can significantly improve the thermal stability of neat ESA. Vicat softening temperature (VST) of composites was obtained higher than epoxy matrix. Additionally, all composites exhibited hydrophobic surfaces. The incorporation of HSh fillers reduces the wetting and hydrophilicity of synthesized epoxy resin.

    更新日期:2020-02-12
  • Evaluation of Crosslinking Effect on Thermo-mechanical, Acoustic Insulation and Water Absorption Performance of Biomass-Derived Cellulose Cryogels
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-12
    Seyedehmaryam Moosavi, Sinyee Gan, Chin Hua Chia, Sarani Zakaria

    Abstract Cellulose cryogels crosslinked with epichlorohydrin (ECH) were successfully developed from kenaf core biomass via green urea/alkaline solvent system. The effect of ECH concentration (from 3 to 9 wt%) on the pore structure, density, morphology, thermal stability, mechanical properties, water absorption performance and acoustic insulation of cellulose cryogels were studied. It was found that the introduction of ECH affected the porosity and pore volume as well as density and water absorption of cryogels. The increase percentage of ECH has delayed the thermal decomposition of the cellulose cryogels thereby improving their thermal stability. Moreover, the compress stress and the sound absorption coefficient of the cellulose cryogels were enhanced significantly by about 50% and 27%, respectively. This work provides a facile approach to produce cost-effective biomass-derived cellulose cryogels with improved mechanical and thermal stability properties as well as acoustic insulation for preliminary studies of industrial applications.

    更新日期:2020-02-12
  • Carbon Dioxide Based Poly(ether carbonate) Polyol in Bi-polyol Mixtures for Rigid Polyurethane Foams
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-07
    Dong Hyun Lee, Jae Hee Ha, Il Kim, Joon Hyun Baik, Sung Chul Hong

    Abstract The utilization of carbon dioxide (CO2) as a sustainable feedstock for chemical products is becoming more interesting topic as the public issue of global warming has been increasingly emphasized. In this study, CO2 was polymerized in the presence of propylene oxide by using a double metal cyanide catalyst, affording poly(ether carbonate) (PEC) polyol. Rigid polyurethane foams (RPUFs) were successfully prepared with a bi-polyol mixture of different compositions containing the CO2-based PEC polyol. Approximately 43 wt% of petroleum-based polyether polyol was successfully substituted by the CO2-based PEC polyol, affording RPUFs with controlled characteristics. The properties of the RPUFs, such as apparent density, compressive strength, thermal conductivity, thermal stability and cell morphology, supported the potential of the RPUFs as thermal insulating materials and CO2 as an eco-friendly sustainable resource.

    更新日期:2020-02-07
  • Adsorptive Remediation of Congo Red Dye in Aqueous Solutions Using Acid Pretreated Sugarcane Bagasse
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-06
    Abd El-Aziz A. Said, Aref A. M. Aly, Mohamed N. Goda, Mohamed Abd El-Aal, Mohamed Abdelazim

    Abstract Batch adsorption of Congo red (CR) on tartaric acid pretreated sugarcane bagasse was performed via varying the experimental factors such as initial dye concentration, contact time, adsorbent dose and particle size. Tries were done to fit the equilibrium results using isotherms of Langmiur, Freundlich, Tempkin and Dubinin–Radushkevich (D–R). Among these, the Langmuir isotherm is not applicable. However, the other three isotherms exhibit correlation coefficient > 0.95, indicating their well applicability to the studied system. Different kinetic models were applied in order to have an insight on the kinetic adsorption process mechanism.

    更新日期:2020-02-07
  • A New Proposal of Preparation of Different Polymorphs of Nanocellulose from Eucalyptus citriodora
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-06
    Alana G. de Souza, Mariana T. Junqueira, Giovanni F. de Lima, Vijaya K. Rangari, Derval S. Rosa

    Abstract Cellulose is a renewable, sustainable, and high available biopolymer; their common form is the type-I polymorph. However, polymorphic changes are associated with different properties and a wide range of applications. In this study, we proposed a new method to prepare polymorphic cellulose nanostructures (CNSs): first, the CNS were isolated, and then the polymorphs were converted. CNS-I (type-I), CNS-II (type-II), and CNS-III (type-III) were successfully obtained, and the structure, crystallinity, superficial characteristic, morphology, and thermal stability were evaluated. The results showed that CNS-II and CNS-III are more amorphous than CNS-I due to the strong reagents used for the polymorphic conversion, which results in a swelling, increased chain spacing, and structural disorganization. This effectively changed the morphology of the CNS, from cellulose nanocrystals from irregular quasi-spherical nanoparticles. The proposed method allows a wide range of applications, from package and nanocomposites with CNS-I due to its high crystallinity and crystal morphology, to drug carrier, food thickener and biomedical products for CNS-II and CNS-III due to its quasi-spherical shape and more amorphous structure. Graphic Abstract

    更新日期:2020-02-07
  • Soil Inoculation with Pseudomonas geniculata WS3 for Accelerating the Biodegradation Process of In Situ Compatibilized PBS/PLA Blends Doped with HPQM
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-06
    Panupong Srimalanon, Benjaphorn Prapagdee, Narongrit Sombatsompop

    Abstract This work studied the biodegradative activity of Pseudomonas geniculata WS3 and Stenotrophomonas pavanii CH1, PLA-degrading bacteria, on films with different ratios of polybutylene succinate (PBS)/polylactic acid (PLA), in submerged cultures. Effects of PBS, dicumyl peroxide (DCP) and 2-hydroxypropyl-3-piperazinyl quinoline carboxylic acid methacrylate (HPQM) of in situ compatibilized PBS/PLA blends were also examined under soil burial biodegradation at mesophilic and thermophilic conditions. The results from the submerged experiments showed that the weight loss of PBS/PLA blends increased with increasing PBS content. All blending ratios of PBS/PLA were more degraded by P. geniculata WS3 than S. pavanii CH1. After soil burial, PBS/PLA films with 40/60 wt% showed higher biodegradation than those with 20/80 wt% with or without P. geniculata WS3 inoculation. However, the biodegradation of PBS/PLA blends inoculated with P. geniculata WS3 was higher than that of the uninoculated treatment. The addition of DCP in PBS/PLA blends decreased the biodegradation and weight loss. Unexpectedly, the degree of biodegradation and weight loss of PBS/PLA at a ratio of 20/80 wt% with DCP added were higher than that of PBS/PLA at a ratio of 40/60 wt% with DCP added. The addition of HPQM, showing antibacterial properties, decreased the biodegradation of PBS/PLA blends by 1.4 to 1.8-fold compared to those without HPQM addition. It could be concluded that the inoculation of P. geniculata WS3 mainly promoted the biodegradation of PBS/PLA blends under mesophilic condition. However, the addition of DCP and HPQM decreased the biodegradation of the PBS/PLA blends.

    更新日期:2020-02-07
  • Adsorption of Dyes Using Poly(vinyl alcohol) (PVA) and PVA-Based Polymer Composite Adsorbents: A Review
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-05
    Chun Fah Mok, Yern Chee Ching, Farina Muhamad, Noor Azuan Abu Osman, Nguyen Dai Hai, Che Rosmani Che Hassan

    Abstract In recent years, polymeric adsorbent is gaining more interest over classical adsorbents such as clays and activated carbon due to its tunable physicochemical properties, structural diversity, reusability and selectivity. Therefore, the aim of this article is to summarize the available information on the adsorption studies of dyes using PVA and PVA-based polymer composite adsorbents. These materials were reviewed with emphasis on the experimental parameters (initial dye concentration, pH, adsorbent dosage etc.) and outcomes of the various adsorption studies were discussed. Furthermore, the isotherm models, kinetic and thermodynamic of the adsorption studies involved were also summarized. This review outlines the rationale for using the PVA-based composite adsorbents which have demonstrated good removal efficiency for several dyes. Future perspectives of the research work are also being suggested. Graphic Abstract

    更新日期:2020-02-06
  • Mesoporous Crosslinked Chitosan-Activated Charcoal Composite for the Removal of Thionine Cationic Dye: Comprehensive Adsorption and Mechanism Study
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-05
    Ali H. Jawad, Ahmed Saud Abdulhameed, Mohd Sufri Mastuli

    Abstract Chitosan (CS) was coalesced with activated charcoal (AC), followed by crosslinking reaction with epichlorohydrin (ECH) to form a mesoporous crosslinked chitosan–epichlorohydrin/activated charcoal composite (CS-ECH/AC). The structural and physicochemical properties of CS-ECH/AC were characterized by Brunauer–Emmett–Teller, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and point-of-zero charge (pHPZC) analyses. CS-ECH/AC was used to remove thionine (TH), a model cationic dye, from aqueous solution. Batch mode adsorption studies were performed by varying operational adsorption parameters, such as adsorbent dosage (0.04–0.30 g), solution pH (3–11), initial TH dye concentrations (10–100 mg/L), and contact time (0–270 min). The equilibrium data was described well by the Freundlich isotherm, and the maximum adsorption capacity of CS-ECH/AC for TH dye adsorption was 60.9 mg/g at 303 K. The kinetic uptake profiles were well described by the pseudo-second-order model. Thermodynamics results indicated a spontaneous and exothermic adsorption process. The proposed adsorption mechanism included mostly electrostatic attractions, H-bonding interactions, and π–π interactions. All these results showed that CS-ECH/AC can be considered as a feasible biocomposite material for the removal of cationic dyes from wastewater.

    更新日期:2020-02-06
  • Synthesis of Magnetic Chitosan-Fly Ash/Fe 3 O 4 Composite for Adsorption of Reactive Orange 16 Dye: Optimization by Box–Behnken Design
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-03
    Ali H. Jawad, Nurul Najwa Abd Malek, Ahmed Saud Abdulhameed, R. Razuan

    Abstract A hybrid composite biopolymer of magnetic chitosan-fly ash/Fe3O4 (CS-FA/Fe3O4) was prepared to be an effective composite biosorbent for the removal of reactive orange 16 (RO16) dye from aqueous media. Various analytical techniques such as XRF, BET, XRD, FTIR, and SEM–EDX were utilized to characterize of CS-FA/Fe3O4 composite. The effects of adsorption process parameters namely adsorbent dose (A: 0.04–0.12 g), solution pH (B: 4–10), temperature (C: 30–50 °C), and time (E: 20–90 min) were optimized by using Box–Behnken design (BBD) in response surface methodology (RSM). The experimental results indicate that the highest RO16 removal was 73.1% by significant interaction between BC (p-value = 0.0002) and AD (p-value = 0.022). The optimum RO16 dye removal conditions were recorded at solution pH ~ 4, adsorbent dose (0.08 g), temperature (30 °C), and time (55 min). The adsorption process was well described by pseudo-second order (PSO) kinetic and Freundlich isotherm model. The adsorption capacity of CS-FA/Fe3O4 composite for RO16 dye was 66.9 mg/g at 30 °C. The mechanism of the RO16 dye adsorption included many interactions such as electrostatic, n–π interaction, H-bonding, and Yoshida H-bonding. Furthermore, the CS-FA/Fe3O4 composite exhibited a high ability to separate from the aqueous solution after adsorption process by external magnetic field.

    更新日期:2020-02-04
  • Green Biodegradable Thermoplastic Natural Rubber Based on Epoxidized Natural Rubber and Poly(butylene succinate) Blends: Influence of Blend Proportions
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-03
    Parisa Faibunchan, Skulrat Pichaiyut, Claudia Kummerlöwe, Norbert Vennemann, Charoen Nakason

    Abstract Green biodegradable thermoplastic natural rubber based on epoxidized natural rubber (ENR) and poly(butylene succinate) (PBS) blends was prepared via simple blend (SB) or via dynamic vulcanization (DV). Influence of blend proportions of ENR and PBS on morphological, dynamic, mechanical, dynamic mechanical, thermal properties, and water absorption together with biodegradability were investigated. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were also used to assess phase morphologies in the ENR/PBS blends. It was found that the ENR/PBS simple blend had co-continuous phase structure, while the dynamically cured ENR/PBS blend (DV) has spherical micron-sized crosslinked ENR particles dispersed in the PBS matrix. In addition, the particle size of vulcanized ENR domains of DV and the grain size of ENR and PBS phases in the simple blend decreased with increasing PBS content up to 50 wt%. This might be caused by interfacial adhesion effects between the phases. However, increasing the ENR fraction to 70 wt% caused increasing of elasticity in terms of shear viscosity, shear modulus, storage modulus, together with elongation at break, and tension set. It was also found that mechanical and thermal properties as well as biodegradability of dynamically cured ENR/PBS blends were better than for the simple blend counterparts, That is, the lowest biodegradability, as indicated by the least weight loss, is seen for the 50/50 ENR-25/PBS simple blend (about 1.2%) and dynamic vulcanizate (about 0.6%).

    更新日期:2020-02-04
  • Eco-friendly Waterborne Alkyd Resin from Polyethylene Terephthalate Waste
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-02-03
    Yangmin Ma, Rui Lei, Xiufang Yang, Fangzhou Yang

    Abstract This work reports a simple and ecofriendly way of recycling polyethylene terephthalate (PET) waste. PET waste was glycolyzed using trimethylolpropane (TMP) giving tetra-functional glycolyzate, to prepare alkyd resin. 0.25% ZnOAc and the TMP to PET molar ratio of 12:1 at 220 °C produced the best yield of glycolyzate. The obtained glycolyzate was characterized by Fourier transform infrared spectroscopy (FTIR) spectroscopy, 1H and 13C nuclear magnetic resonance (NMR) and further used in the synthesis of alkyd resins. The properties of the prepared alkyd resins including acid value, the pencil hardness, chemical resistance and thermal stability, were investigated. The pencil hardness of the cured resins film is 3H, which is better than the commercial alkyd resin YF-155. Thermogravimetric analysis (TGA) exhibited polymer decomposition occurred above 160 °C. When compared to commercial coatings, Zanthoxylum bungeanum seed oil (ZSO)-based alkyd resin from postconsumer PET bottles has potential for commercial applications, and may even be superior in thermal and chemical resistance.

    更新日期:2020-02-03
  • Silver Nanoparticles Embedded in Gelatin Biopolymer Hydrogel as Catalyst for Reductive Degradation of Pollutants
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-22
    Tahseen Kamal, Mohammad Sherjeel Javed Khan, Sher Bahadar Khan, Abdullah M. Asiri, Muhammad Tariq Saeed Chani, Muhammad Wajid Ullah

    Abstract In the present article, a facile method for the self-synthesis of silver nanoparticles without the use of reducing agent in a gelatin biopolymer hydrogel and its utilization as a catalyst for the pollutants reduction reactions is demonstrated. We first synthesized different wt% of the gelatin aqueous solutions at high temperature followed by crosslinking with formaldehyde solution. Among the three different wt% of the gelatin hydrogels, we found that the 8% hydrogel was suitable for this study. The hydrogel was immersed in a 10 mM AgNO3 aqueous solution for three days, after which, the gelatin hydrogel changed its color from transparent to brown color indicating the self-formation of the silver nanoparticles inside the gelatin hydrogel (Ag-GL). Importantly, the formation of the nanoparticles did not require any reductant by using this method. The successful preparation of the Ag-GL was confirmed by FESEM, XRD, EDX and TGA analyses. The Ag-GL was tested as catalyst in the reduction reactions of the methyl orange (MO) and 4-nitrophenol (4-NP). Both of these reactions were progressed with high rate constants (kapp = 0.966 min−1 for MO and 0.621 min−1 for 4-NP were observed). In addition, we discussed the mechanism, influence of the reductant and recyclability of the Ag-GL on the kapp of the both reduction reactions. Graphic Abstract Ag nanoparticles were self-synthesized inside a gelatin biopolymer hydrogel without using the harsh chemicals, which were used as hydrogel reactor for hydrogenation of pollutants.

    更新日期:2020-01-30
  • Production of Biodegradable Film Based on Polylactic Acid, Modified with Lycopene Pigment and TiO 2 and Studying Its Physicochemical Properties
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-26
    Sima Asadi, Sajad Pirsa

    Abstract In this study, a new film based on polylactic acid (PLA) modified with titanium dioxide and lycopene pigment (PLA/TiO2/Lyc) was prepared. To study the effect of titanium dioxide and lycopene pigment on the physicochemical properties of the film, a central composite statistical design was used. The film properties including moisture, thickness, water vapor permeability, antioxidant activity, antimicrobial properties, and color were studied. The SEM, XRD, FT-IR and DSC techniques were used to study film properties. The results showed that moisture content, antioxidant activity, and film thickness was increased and water vapor permeability was decreased significantly with increasing lycopene and titanium dioxide (P < 0.5). Also, with increasing lycopene concentration, the color indices of a*, b* were increased and the lightness of the films was decreased significantly (P < 0.05). The results of antimicrobial activity showed that the addition of titanium dioxide nanoparticles and lycopene pigment caused antimicrobial activity of film against Escherichia coli and Staphylococcus aureus. Surface morphology analysis showed that the titanium dioxide particles (30–100 nm) were dispersed within the film and the lycopene pigment was distributed evenly in the polymer matrix. Lycopene and TiO2 reduced the pores on the polymer surface. The FT-IR results confirmed the interactions between polylactic acid, titanium dioxide and lycopene pigment. XRD showed that both titanium dioxide and lycopene pigment improved the crystalline structure of the poly lactic acid film. DSC results showed that lycopene and titanium dioxide improved the crystalline melting point of the film. The overall results showed that the prepared film can be used as an antimicrobial and antioxidant film with suitable color properties for active and intelligent packaging in food.

    更新日期:2020-01-30
  • Physicochemical Structure Analysis of Chitin Extracted from Pupa Exuviae and Dead Imago of Wild Black Soldier Fly ( Hermetia illucens)
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-27
    Debasree Purkayastha, Sudipta Sarkar

    Abstract Chitin is the second most widely available natural fiber with diverse applications. Insect chitin is gaining popularity over the last decade. Black soldier fly is a widely known insect with waste management potential. In this study, chitin was isolated from Black soldier fly (Hermetia illucens) pupae exuvia (BSFE) and imago (BSFI). The chitin content was found to be 9% and 23% for pupae exuviae and imago respectively. Both the chitins were α-chitin. The degree of acetylation (DA) confirms that BSFE chitin has higher purity than BSFI chitin. The BSFE chitin is more amorphous than BSFI chitin. The crystallinity index (CrI) for BSFE and BSFI chitin was 25.20% and 49.4%, respectively. Both the chitins had good thermal stability with a maximum degradation (DTGMax) of BSFI and BSFE chitin at 363 °C and 371 °C, respectively. The Brunauer–Emmett–Teller (BET) study showed that chitin from BSFI was mesoporous with well defined cylindrical pore channels while the chitin from BSFE was non-porous. The surface area of BSFE and BSFI chitin was 1.63 and 23.00 m2/g respectively. Both the chitin had a smooth microfibrillar structure with repeating units. Based on the physicochemical characteristics of the BSF-derived chitin it can find promising commercial applications in tissue engineering, textile industry and as an adsorbent in water and wastewater treatment.

    更新日期:2020-01-30
  • Bio-based Poly(ɛ-caprolactone) from Soybean-Oil Derived Polyol via Ring-Opening Polymerization
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-19
    Gokhan Acik

    Abstract In this work, a new series of bio-based poly(ɛ-caprolactone)s (SBO-PCLs) is synthesized through ring-opening polymerization (ROP) of ɛ-caprolactone (ɛ-CL) using stannous octoate as a catalyst and hydroxylated soybean oil (SBO-OH) as a macro-initiator. For this purpose, firstly, epoxy groups of epoxidized soybean oil (ESBO) are converted to hydroxyl functionalities to be used for ROP of ɛ-CL. Then, after the ROP of ɛ-CL using SBO-OH; wettability, biodegradability and thermal properties of the obtained SBO-PCLs are evaluated in terms of loading ratio of ɛ-CL monomer ([OH]/[ɛ-CL] (n/n) = 1:0.5; 1:1 and 1:2). The obtained SBO-PCLs and their intermediates are characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), gel permeation chromatography (GPC), water contact angle measurement (WCA), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and enzymatic degradation experiment. SBO-PCL with higher PCL molar ratio shows the lower biodegradability, but higher hydrophobicity and thermal properties compared to others. Thus, it is clear that the successful syntheses of SBO-PCLs encourage the use of these polymers as promising materials for scientists working on PCL applications.

    更新日期:2020-01-30
  • Modified Biopolymer (Chitin–Chitosan Derivatives) for the Removal of Heavy Metals in Poultry Wastewater
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-22
    Ernestine Atangana, Paul J. Oberholster

    Abstract In the meat production industry, large volumes of wastewater are generated containing great quantities of organic matter that requires y safe disposal or utilization. As a result, management of poultry wastewater is of great concern worldwide. However, problems associated with wastewater disposal are a well-known phenomenon. Nevertheless finding solutions to treat different waste types are not always an orderly method to solve and this have cause a lot of adverse effects on the receiving environment. In the current study, chitosan was synthesized from shrimp chitin to determine its usefulness in removing heavy metals from meat wastewater. Factors for example yield, moisture and ash content and deacetylation (DDA) were tested as well and results showed that chitosan was a source from shrimp chitin. Structural properties such FTIR, SEM and XRD were used to determine the structural morphology, and the final results implies successful isolation of chitosan. Modification of chitosan product was then accomplished via cross-linked chitosan with a series of cross-linking agent; glutaraldehyde, epichlorohydrine, p-benzoquinone s-methylbutylamine and 1,3-dichloroaceone adsorbents. Satisfactory percentages were obtained from shrimp chitosan cross-linked s-methylbutylamine, glutaraldehyde and epichlorohydrine (63–72%) whereas lower yield was observed from chitosan starch cross-linked p-benzoquinone (57%). The usefulness of the chitosan modified products were then investigated in purifying wastewater effluent using HG-AAS. Results of qualitative and quantitative analysis on the elemental content showed the presence of the following elements present in different concentrations: Pb, Cr, Cu, Fe and Zn in the meat wastewaters. Lower concentration ranges (0.01–0.9 mg/L) of these heavy metals were observed for Pb(II), Cr(VI), Cu(II), Fe(II) and Zn(II) after testing the different chitosan cross-linked products (A–E). Among all the metals tested, shrimp chitosan cross-linked with 1,3-dichloroacetone was found to be the most effective product for heavy metals removal. These results also revealed that there is a decrease in the amount of heavy metals present in meat wastewater effluent.

    更新日期:2020-01-30
  • Preparation and Characterization of Chitosan/Gelatin-Based Active Food Packaging Films Containing Apple Peel Nanoparticles
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-25
    Asad Riaz, Camel Lagnika, Mohamed Abdin, Malik Muhammad Hashim, Waqar Ahmed

    Abstract Bio-based active food packaging containing natural antioxidants has gaining great attention these days. The food industry resulted in huge amount of waste rich in natural antioxidant and utilization of these wastes is very important from environmental viewpoint. In this study, apple peel was used to produce apple peel nanoparticles and later, chitosan (CS) and gelatin (G) based novel functional films were successfully fabricated. The prepared films were characterized for their structure, potential interaction and thermal stability. In addition, tensile strength and physical properties were also determined. Scanning electron microscopy (SEM) results revealed that higher concentration of apple peel ethanolic extract (APEE) triggered the sintering of nanoparticles within the films. The data of Fourier transform-infrared spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA) revealed that the presence of apple peel related compounds in the films resulted decrease in availability of hydroxyl groups within the polymer matrix. The addition of APEE into CS/G significantly enhanced the physical properties of the film by increasing its thickness while solubility, swelling ratio, and water vapor permeability were decreased. It could be inferred that CS/G-APEE films exhibited good antioxidant properties, indicating that it could be developed as a bio-nanocomposite food packaging material for the food industry.

    更新日期:2020-01-30
  • Enzymatic Degradation and Pilot-Scale Composting of Cellulose-Based Films with Different Chemical Structures
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-27
    Ilona Leppänen, Minna Vikman, Ali Harlin, Hannes Orelma

    Abstract In this study, we investigated the enzymatical degradability and pilot-scale composting of 14 cellulose-based materials. The materials analyzed here were cellulose regenerated from ionic liquid (EMIM[OAc]), carboxymethyl cellulose (CMC) crosslinked by aluminum salt (Al-salt), methyl cellulose, cellulose acetate, butylated hemicellulose: DS: 1, DS: 0.4, and DS: 0.2, cellophane, wet strength paper, nanocellulose, paper partially dissolved by IL, cellulose carbamate, cellulose palmitate, and cellulose octanoate. The aim of the study was to show how chemical substituting and the substituent itself influence the biodegradability of cellulose materials. The enzymatic degradation and pilot-scale composting of these films shows the correlation between the hydrolysis rate and degree of substitution. The enzymatic hydrolysis of cellulose-based films decreased exponentially as the degree of substitution increased. Modifying cellulose to the extent that it gains the strength needed to obtain good mechanical properties, while retaining its natural biodegradability is an important factor when preparing alternatives for plastic films. Graphic Abstract

    更新日期:2020-01-30
  • Recycling of Quaternary Household Plastic Wastes by Utilizing Poly(Ethylene-co-Methacrylic acid) Copolymer Sodium Ion: Compatibility and Re-processability Assessments
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-28
    Divya Rajasekaran, Pradip K. Maji

    Abstract The recycling of quaternary plastic wastes irrespective of their chemical nature into a value-added material has been investigated in this paper. Household plastic wastes like polyethylene terephthalate bottles, polyethylene bags, polyvinyl chloride sheets, and polypropylene decorative ribbons were recycled based on their polarity by utilizing poly (ethylene-co-methacrylic acid) copolymer sodium ion. The composition of the blend is varied by altering the level of loading of a two-phase compatibilizer. The composition with 7 wt% loading of compatibilizer showed improved properties than the neat blend. Tensile strength and elongation at break (%) improvement of 117% and 485%, respectively reflected in the composition containing 7 wt% of ionomer as a compatibilizer on comparing with 0 wt% of ionomer, making them ideal composition. The compatibilization and improved mechanical performances were supported by nanometric level phase morphological characteristics. The stability and thermal degradation of the compositions are discussed through thermal analysis. Comparative study on repeated processing up to three cycles and their compatibilization mechanism based on polarity has been reported here.

    更新日期:2020-01-30
  • Amidoxime Modified Polymers of Intrinsic Microporosity (PIM-1); A Versatile Adsorbent for Efficient Removal of Charged Dyes; Equilibrium, Kinetic and Thermodynamic Studies
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-27
    Bekir Satilmis

    Abstract Polymers of Intrinsic Microporosity (PIMs) are recognized as promising polymers for active separation of organic pollutants. These highly porous and solution-processable polymers could be tailored to remove specific targets from an aqueous system. In this study, PIM-1 powder was modified to amidoxime PIM-1 powder and adsorption of charged dyes which are Methylene Blue (MB, cationic) and Methyl Orange (MO, anionic) from an aqueous system was explored to evaluate the influence of contact time, initial concentration, solution pH and temperature on the removal of dyes. The adsorption reached the equilibrium within three hours in a batch adsorption process for both dyes. Experimental adsorption capacity (qe, exp) of Amidoxime PIM-1 was found as 79.8 mg g−1 and 69.8 mg g−1 for MO and MB, respectively at pH 6 and 298 K. The Amidoxime PIM-1 was also able to remove a mixture of anionic and cationic dyes simultaneously from aqueous system. The removal ability is dependent on the solution pH and the selectivity can be tuned by shifting solution pH such as at low pH (pH 3) anionic dye adsorption is more favourable, while at high pH (pH 10) cationic dye adsorption is preferable. Equilibrium data acquired from batch adsorption experiments have been examined by four two-parameter (Langmuir, Freundlich, Temkin and Dubinin–Radushkevich), four three-parameter (Redlich–Peterson, Sips, Khan and Liu) isotherm models, and by kinetic models such as the pseudo-first-order, the pseudo-second-order, Elovich equation and intraparticle diffusion using non-linear regression technique. Combination of several errors analysis techniques was applied to find the best fitting isotherm and kinetic models. Liu isotherm was the best to define the experimental data and the maximum adsorption capacities (qm) were calculated as 86.7 mg g−1 and 81.3 mg g−1 for MO and MB, respectively at pH 6 and 298 K. Adsorption data have the best consistency with the pseudo-second-order kinetic model. Furthermore, thermodynamic parameters were determined and the experiments suggested that the adsorption of MB and MO onto Amidoxime PIM-1 is a physical, spontaneous and exothermic. Graphic Abstract

    更新日期:2020-01-27
  • High-Strength Chitin Based Hydrogels Reinforced by Tannic Acid Functionalized Graphene for Congo Red Adsorption
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-25
    Cuiyun Liu, Hongyu Liu, Keyong Tang, Keke Zhang, Zhaoxiang Zou, Xiping Gao

    Abstract In this study, a novel chitin based composite hydrogel reinforced by tannic acid modified reduced graphene oxide (TRGO) was prepared via a facile freezing–thawing approach. Epichlorohydrin (ECH) and TRGO sheets were employed as efficient crosslinkers to fabricate dually crosslinked TRGO/chitin composite hydrogels with advanced mechanical and adsorption properties. Results indicated that the TRGO reinforced chitin composites increased the mechanical property remarkably with exhibiting compression strength from 22.7 kPa for neat chitin hydrogel to 72.3 kPa for the hydrogel with loading of 7% TRGO. Multiple interactions such as hydrogen bonding between TRGO and chitin as well as the dually covalent crosslinking bonds were responsible for the extensive improvement in compression strength. Furthermore, the TRGO reinforced hydrogels exhibited an excellent adsorption capacity towards Congo red (CR). The maximum adsorption capacity of CR was 230.5 mg g−1 for chitin hydrogel with loading of 7% TRGO. The adsorption of CR was found following the Langmuir isotherm and pseudo-second-order models. Hence, the prepared TRGO/chitin hydrogels provide an easy and efficient way for the removal of CR dye from wastewater.

    更新日期:2020-01-26
  • Characterization of Polyhydroxyalkanoate Produced by Halomonas venusta KT832796
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-25
    Angelina Stanley, P. S. Keshava Murthy, S. V. N. Vijayendra

    Abstract Halophilic microorganisms produce several metabolites having potential application in biotechnology and industry. They also produce polyhydroxyalkanoates (PHA), which are suitable replacements for conventional plastics for packaging food and non-food materials due to their biocompatible and biodegradable properties. PHA produced by the native isolate of Halomonas venusta KT832796 using a minimal medium was made into a film. It was characterized using Fourier Transform Infrared (FTIR) spectroscopy, Nuclear Magnetic Resonance (NMR) spectroscopy, GC–MS, UTM (Mechanical strength), Differential Scanning Calorimetry (DSC) and X-ray diffraction (XRD) analysis. Based on FTIR, NMR and GC–MS analyses the polymer produced by Halomonas venusta KT832796 was found to be poly(3-hydroxybutyrate). The polymer had a tensile strength of 26 MPa and Young’s modulus of 3 GPa and the melting temperature Tm 173.59 °C, which are found to be similar to the standard PHB polymer and the crystalline state was revealed by XRD pattern. This PHB polymer can be used in food packaging systems and medical applications for drug delivery. This is the first communication on characterization of PHA produced by Halomonas venusta.

    更新日期:2020-01-26
  • Catalytic Application of Silver Nanoparticles in Chitosan Hydrogel Prepared by a Facile Method
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-24
    Mohammad Sherjeel Javed Khan, Sher Bahadar Khan, Tahseen Kamal, Abdullah M. Asiri

    Abstract In this research work, a simple method of silver nanoparticles’ self-synthesis in chitosan (CH) biopolymer hydrogels without utilizing a reducing agent is shown. The synthesized material was used as a catalyst in different reduction reactions. For this purpose, different amounts of CH powder were dissolved in acidic aqueous solutions and then crosslinked it with the formaldehyde solution to make a CH biopolymer hydrogel. Among all the prepared samples, a CH hydrogel prepared from a dense solution was found to be suitable for this study because of good mechanical stability. For the self-synthesis of silver nanoparticles inside hydrogel, it was immersed in an aqueous solution of AgNO3 (10 mM) for 3 days at room temperature. The color of the chitosan hydrogel changed to brown from transparent which indicated the successful formation of silver nanoparticles on CH hydrogel (Ag-CH). No reducing agent for conversion of the Ag1+ ions to nanoparticles in this whole synthesis method. Instrumental techniques such as FESEM, XRD and EDX analysis confirmed the successful preparation of Ag-CH. The Ag-CH was checked as a catalyst in the 2-nitrophenol (2-NP) and acridine orange (ArO) reduction reactions. Both reactions were carried out at high rate constants (2-NP = 0.260 min−1, ArO = 0.253 min−1) by using the Ag-CH hydrogel catalyst. In addition, we discussed the mechanism of action of the reducing agent, the effect of kapp on the two reduction reactions of Ag-CH and the recyclability.

    更新日期:2020-01-24
  • A Review of the Sustainable Approaches in the Production of Bio-based Polyurethanes and Their Applications in the Adhesive Field
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-22
    Adrián Tenorio-Alfonso, Mª Carmen Sánchez, José Mª Franco

    Abstract On account of the irreversible environmental damage caused by the utilization of non-renewable raw materials in industrial production, since the end of the twentieth century, the interest in replacing the traditionally applied petroleum-based starting compounds in the polyurethane production by more sustainable feedstocks has grown enormously. Such pursuit of Green Chemistry has been fostered by the implementation of a set of national and international initiatives and stricter regulations, especially in the field of adhesives. In this respect, the latest advances in the production of bio-based polyurethanes are collected in this review. Thus, after a brief introduction to this subject and main tendencies towards the production of more sustainable polyurethanes, the first section reviews the feasibility of manufacturing polyurethanes from a range of natural platforms, including lignocellulosic biomass and vegetable oils, whether modified or in their original form, along with some industrial wastes. Afterwards, the hitherto considered synthetic routes for the preparation of greener polyurethanes are assessed, encompassing waterborne, radiation-curable and non-isocyanate polyurethane techniques. Finally, the last section focuses on the research advancement on the synthesis, properties and different uses of bio-based polyurethanes specifically implemented in the field of adhesives.

    更新日期:2020-01-23
  • Flame Retardant Properties and Thermal Stability of Polylactic Acid Filled with Layered Double Hydroxide and Rice Husk Ash Silica
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-20
    Chuenkhwan Tipachan, Rakesh K. Gupta, Sushant Agarwal, Somjai Kajorncheappunngam

    Abstract Polylactic acid (PLA) samples containing a layered double hydroxide modified with sodium dodecyl sulfate (PKL_DS), silica from rice husk ash (SiRHA) and a combination of the two nanofillers were prepared by both solvent casting and a more practical approach involving dry blending of constituents and their melting in a mixing tank followed by compression molding. The morphology of the nanocomposite films was investigated using transmission electron microscopy (TEM) and X-ray diffraction (XRD), and it was confirmed that the nanocomposite structures were intercalated. Additionally, SEM pictures of surfaces of nanocomposite films suggest that PKL_DS was well dispersed throughout the PLA matrix, and the films were essentially featureless except at the highest concentration examined. In the case of SiRHA, there was filler aggregation at low concentration, while holes and cavities were clearly visible at higher concentrations. The addition of PKL_DS to films containing SiRHA ameliorated these effects, and ultimately a dense structure was obtained. From TGA results, it was determined that only the addition of SiRHA significantly improved the thermal stability of PLA. The flammability performance of PLA nanocomposites was investigated using limiting oxygen index (LOI) and UL-94V type measurements. A maximum LOI value of 32.8% could be achieved for PLA nanocomposites containing 10 wt% PKL_DS and 5 wt% SiRHA. This was 78% higher than the LOI of neat PLA alone. Furthermore, PLA containing 10 wt% PKL_DS and 3–5 wt% SiRHA attained a V-0 rating on UL-94 type tests with anti-dripping behavior. It was found that there was synergism between PKL_DS and SiRHA, and this was very effective in improving the flame retardant performance of PLA. That this performance came about without having to completely exfoliate the nanofillers is a remarkably useful result.

    更新日期:2020-01-21
  • Arsenic Sorption on Chitosan-Based Sorbents: Comparison of the Effect of Molybdate and Tungstate Loading on As(V) Sorption Properties
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-17
    Pamela V. Sierra-Trejo, Eric Guibal, José F. Louvier-Hernández

    Abstract Modified chitosan gel beads, prepared by molybdate and tungstate coagulation methods, were tested for As(V) removal from solutions in the range of 5–200 mg As L−1. The sorbent is efficient at removing As(V) from acid solutions (optimum pH close to 3), the sorption capacities for As uptake in molybdate- and tungstate-loaded beads are 75 and 44 mg As g−1 of dry mass, respectively. The mechanism of As(V) sorption is related to the ability of molybdate and tungstate ions to complex As(V) ions in acid solutions. As(V) sorption process is mainly influenced by the presence of phosphate ions, but there is no influence of co-ions as nitrate and chloride. Arsenic desorption can be performed using phosphoric acid solutions. Arsenic adsorption proceeds in acidic solutions with a partial release of molybdate and tungstate and with residual concentrations of arsenic above the regulations for drinking water. For that reason, this material is a candidate for the treatment of industrial effluents. Graphic Abstract

    更新日期:2020-01-17
  • Cardanol-Imidazole Based Benzoxazine Blends and Bio-silica Reinforced Composites with Enhanced Surface, Thermal and Dielectric Properties
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-10
    Govindraj Latha, Arumugam Hariharan, Pichaimani Prabunathan, Muthukaruppan Alagar

    Abstract In the present work, imidazole core mono-amine (ima) was synthesized and used with cardanol (C) and bisphenol-F (BF) to obtain corresponding benzoxazines (C-ima and BF-ima) respectively. Similarly aniline (a) was used as amine precursor for synthesis of benzoxazines (C-a and BF-a) of cardanol (C) and bisphenol-F (BF) respectively for the purpose of blending and comparative studies with ima based benzoxazines. Benzoxazines (C-ima, C-a, BF-ima and BF-a) matrices and blends were prepared using both monofunctional and bifunctional benzoxazines in different weight percent (25/75 wt%, 50/50 wt% and 75/25 wt%) ratios and were characterized using different analytical techniques. From DSC analysis, it was observed that the curing temperature obtained for imidazole based benzoxazines (C-ima and BF-ima) was significantly lower than that of benzoxazines (C-a and BF-a) made using conventional aniline. Similarly, the blends prepared using ima based benzoxazine possess the lower curing temperature, with enhanced thermal stability and char yield than those of conventional cardanol-aniline benzoxazines to an appreciable extent. Hybrid blend composites were developed by reinforcing varying weight percentages (1, 3, 5, 7 and 10 wt%) of GPTMS functionalized bio-silica with selected blends (50:50) of imidazole based benzoxazines (C-ima and BF-ima) and their properties were studied. Data obtained from different studies, suggest that these hybrid composites possess an enhanced thermal stability, higher values of Tg, improved hydrophobic behavior, higher value of char yield and lower dielectric constant than those of neat matrices and blended matrices. It is concluded that the imidazole amine based benzoxazines (C-ima and BF-ima) blends and hybrid composites developed in the present work possess better properties than those of conventional benzoxazine based materials, hence it is suggested that these blends and composites can be used for high performance thermal and dielectric applications.

    更新日期:2020-01-11
  • Design of AgNPs -Base Starch/PEG-Poly (Acrylic Acid) Hydrogel for Removal of Mercury (II)
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-10
    Atefeh Saberi, Mohammad Sadeghi, Eskandar Alipour

    Abstract In the present study, we introduce the formation of Starch/PEG-poly (acrylic acid) hydrogel (St-PEG-AcAH) and nanocomposite of AgNPs-base St-PEG-AcAH (AgNPs-St-PEG-AcANCH) free radical method, and their characterization using analytical techniques of FT-IR, TEM, SEM, EDX, AFM, XRD, TGA/DTG. The thermodynamic parameters and application of prepared hydrogels was investigated for the removal of Hg2+ ions in water and the various solvents such as ethanol-water (30:70), ethanol-water (50:50), 2-propanol–water (40:60), respectively. The maximum adsorption capacity of Hg2+ ions for St-PEG-AcAH and AgNPs-St-PEG-AcANCH was achieved 158.21 mg/g and 182.53 mg/g in pH 7 and 6 in aqueous solutions, respectively. On the other hand, the results of adsorption isotherms revealed that adsorption process for both adsorbents occurred as a homogenous and monolayer process with L-shape isotherm. Furthermore, investigating the bioactivity of bioadsorbents, the good antimicrobial efficiency of the prepared samples was confirmed on E. coli bacteria.

    更新日期:2020-01-11
  • Effect of Liquefied Lignin Content on Synthesis of Bio-based Polyurethane Foam for Oil Adsorption Application
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-09
    Raziyeh Mohammadpour, Gity Mir Mohamad Sadeghi

    Abstract The present study focused on synthesizing polyurethane foams with different contents of liquefied lignin. To fulfill that, the weight ratios of liquefied lignin to polypropylene glycol triol (PPG as chain extender) were altered from 25 to 100%. The lignin based polyurethane foams (LPUFs) were characterized by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), scanning electron microscopy (SEM), and compression strength test. The experimental results revealed that LPUFs structures became more disorganized and their density diminished while their heat stability increased with increasing lignin polyol content. Moreover, the specific compressive properties of LPUFs grew from 1.35 to 35.23 kPa Kg−1 m3 and their glass transition temperature elevated from 38.5 to 90 °C with an increase in lignin polyol due to the three-dimensional lignin structure. Finally, the oil adsorption behavior of LPUFs was studied with Langmuir, Freundlich and Redlich–Peterson isotherms. It was observed that oil adsorption properties enhanced for LPUFs with higher contents of lignin polyol. The current work demonstrated that lignin polyol in polyurethane formulation even up to high concentrations, can be appropriately used in the production of soft and rigid bio based foams for different applications such as bio-friendly oil absorbent.

    更新日期:2020-01-09
  • Starch/Poly(butylene succinate) Compatibilizers: Effect of Different Reaction-Approaches on the Properties of Thermoplastic Starch-Based Compostable Films
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-11
    Barbara Fahrngruber, Marta Fortea-Verdejo, Rupert Wimmer, Norbert Mundigler

    The property profile of thin thermoplastic starch (TPS)/poly(butylene succinate) (PBS) films was investigated and the potential improvement, which can be achieved due to the utilization of hydrophilic/hydrophobic compatibilizer systems, was assessed. The evaluation in terms of morphology exhibited a very good TPS dispersion (under optimized processing conditions) within the polyester matrix, while an average particle size of 1.5 µm was obtained. Two different raw material approaches were applied for the preparation of the compatibilizers: (a) native corn starch and (b) destructurized TPS. In the course of the compounding process 0.5 and 1.0 wt% of the two compatibilizer systems (a) and (b) were added. In comparison, the addition of the TPS-based compatibilizer resulted in improved incorporation of TPS within the polyester matrix, which was accompanied by higher tensile strength and tear resistance. Explanations for this observation could be that pre-plasticized starch provides a larger reaction surface and enables better homogenization during the course of compounding. In contrast, for native starch the reaction only can take place at the granule surface and thus, the compatibilization was less efficient. The outcome of this investigation is a compostable film material with high bio-based content, which exhibits great potential for single-use, light-weight packaging applications.

    更新日期:2020-01-09
  • The Effect of Hydroxyapatite Prepared by In Situ Synthesis on the Properties of Poly(Vinyl Alcohol)/Cellulose Nanocrystals Biomaterial
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-10-26
    Panee Panyasiri, Nga Tien Lam, Prakit Sukyai

    Polyvinyl alcohol/cellulose nanocrystals (CNC) and hydroxyapatite (HA) (PCH) were combined using an in situ method to fabricate porous scaffolds. CNC was extracted from sugarcane bagasse and the effect of HA on PVA/CNC composites was varied with 0, 0.5, 1 and 3 wt%. The scanning electron microscopy images of the PCH composites showed interior pores with pore channels, while the energy dispersive spectroscopy (EDS) results confirmed the increased HA content in the nanocomposite with a Ca/P ratio of 1.67. Porosity and the equilibrium swelling ratio were slightly affected by the HA content. The Fourier transform infrared spectra supported the EDS results by identifying significant peaks belonging to the HA curves of the PCH composites. The crystallinity revealed decreased crystal regions at higher HA content, whereas the mechanical behavior showed the improvement at 0.5 wt% of HA. Cytotoxicity with L929 demonstrated the compatibility of the PCH composites, with 85 ± 0.92% cell viability.

    更新日期:2020-01-09
  • Polymer Nanocomposites Based on Poly(ε-caprolactone), Hydroxyapatite and Graphene Oxide
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-20
    Gabriela S. Medeiros, Pablo A. R. Muñoz, Camila F. P. de Oliveira, Laura C. E. da Silva, Ritika Malhotra, Maria C. Gonçalves, Vinícius Rosa, Guilhermino J. M. Fechine

    Standard and hybrid polymer nanocomposites based on poly(ɛ-caprolactone) (PCL), hydroxyapatite (HAp) and graphene oxide (GO). The GO synthetized here is made up of multilayer graphene oxide (mGO), in which up to five layers are stacked and lateral size around of 1 µm. The nanocomposites (PCL/Hap, PCL/mGO and PCL/HAp/mGO) were prepared by melt mixing in a twin-screw extruder and characterized by mechanical test, transmission electron microscopy (TEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), contact angle (CA), surface zeta potential by streaming and cell proliferation. The HAp content was maintained at 20% (w/w) while mGO was used at three levels of content (0.05, 0.1, and 0.3 w/w). In terms of bulk properties, the presence of mGO even in very low content (0.05 to 0.3%) was very effective in order to increase mechanical properties of PCL (stress and strain at beak and tenacity) while HAp tends to decrease them. When the two fillers are inserted mGO act to recover the properties lost by the presence of HAp. TEM images showed single GO sheets very well dispersed alone or combined with HAp. For surface properties, significant changes have been achieved by the presence of mGO, HAp and mGO/HAp. The water contact angle drops to values below 90° for all nanocomposites making the material hydrophilic, but again by the presence of only 0.05% of mGO it was reached easily. Surface ξ-potential for all nanocomposite was lower than neat PCL. As a consequence of surface modifications improvements in cell proliferation ability could be also observed. All modification by the presence of GO point out these materials as excellent candidates to resorbable suture, drug delivery system, and bone graft substitutes.

    更新日期:2020-01-09
  • Nano-Ag/DLC/Cellulose Free-Standing Films Towards Anti-bacterial and Bio-compatible Futuristic Bandage Applications
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-15
    Debabrata Das, Rajkumar Dey, Subhadeep Das, Shamima Hussain, Anup Kumar Ghosh, Arun Kumar Pal

    Abstract Nano-Ag/DLC/cellulose composite free-standing films were deposited by using hybrid chemical routes. Cellulose fibers were extracted from banana pseudostem fibers by chemical route. Modulation of bonding environment on cellulose upon nano-Ag and diamond-like carbon (DLC) inclusions was studied by X-ray photoelectron spectroscopy (XPS), Raman and Fourier transformed infrared spectroscopy (FTIR) measurements. Changes in microstructural and bonding environmental properties of the cellulose films with nano-Ag and DLC loadings were also addressed. These composite films would harness the development of anti-bacterial and bio-compatibility in futuristic bandage applications. Antibacterial studies using Staphylococcus aureus (gram positive) and Escherichia coli (gram negative) bacteria were carried out on the above n-Ag/DLC/cellulose composite films.

    更新日期:2020-01-09
  • Enhancing the Thermal, Mechanical and Swelling Properties of PVA/Starch Nanocomposite Membranes Incorporating g-C 3 N 4
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-10-25
    Arooj Ahmed, Muhammad Bilal Khan Niazi, Zaib Jahan, Ghufrana Samin, Erum Pervaiz, Arshad Hussain, Muhammad Taqi Mehran

    A ground-breaking and soft nanomaterial, namely graphitic carbon nitride (g-C3N4) has gained importance as two-dimensional filler in polymeric membranes. In this research, g-C3N4 was synthesized by “thermal oxidation etching process”, employing melamine as a precursor. The porous nanosheets were characterized by SEM, XRD and FTIR. g-C3N4 nanosheets showed remarkable thermal stability up to 620 °C. The PVA starch nanocomposite membranes were fabricated with varying amounts of g-C3N4. Owing to strong interactions between g-C3N4, and polymers, the composite membranes showed exceptional thermal and mechanical stability and resist to degrade in various mediums including water, saline and blood. The hybrid membranes showed remarkable swelling abilities up to 96 h. Moreover, g-C3N4 enhanced the hydrophilicity, consequently, moisture retention capability and water vapor transmission were improved. XRD and SEM results revealed the proper dispersion of g-C3N4 into the polymeric matrix. The results suggested that prepared hybrid PVA/St/g-C3N4 membranes could be used as wound dressings.

    更新日期:2020-01-09
  • Reducing Biochar Particle Size with Nanosilica and Its Effect on Rubber Composite Reinforcement
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-19
    Steven C. Peterson, Sanghoon Kim

    Abstract Since biochar is a renewable source of carbon, it has been examined as a substitute for carbon black as rubber composite filler. Although biochar can approach carbon black in terms of carbon and ash content, substituting carbon black with biochar typically degrades the mechanical properties of rubber composites because of the much larger particle size of biochar. Biochar is produced from biomass and must be size reduced by “top-down” methods such as milling. Thus, biochar frequently has populations of particles greater than 10 µm in diameter, which greatly reduce reinforcement properties by introducing localized stresses in the rubber composite. In this work we explore using nanosilica as a co-milling material with biochar as a means to reduce its particle size and consequently improve its ability to replace carbon black as rubber composite filler. Biochar co-milled with 1 wt% nanosilica was able to replace 40% of the carbon black filler in a styrene–butadiene rubber composite with virtually no loss in tensile strength. Also, elongation and toughness properties of the optimal biochar substituted composites were improved by over 31 and 24%, respectively.

    更新日期:2020-01-09
  • Recycling of an Agricultural Bio-waste as a Novel Cellulose Aerogel: A Green Chemistry Study
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-20
    Mehmet Kaya, Ahmet Tabak

    Abstract Cellulose aerogel (CA) isolated from tea stem wastes (TSW) is a good fire retardant and heat insulator, environmentally friendly, thermally stable and highly porous material with a network structure. These outstanding properties have attracted a huge interest in the materials world. In this study, firstly, following delignification and removing hemicellulose, pure raw cellulose was isolated using TSW, hydrogel form of cellulose was prepared by regeneration of cellulose solution, and then, the final product (CA) was produced via freeze-drying. The data results showed that the aerogel had a three dimensionally network structure. Moreover, it can be deduced that thermal durability of the studied CA could be effective because of its fire retardant and heat insulating property. In addition, the production process of CA is easily available at low cost and sustainable.

    更新日期:2020-01-09
  • Graft Copolymerization of Crosslinked Polyvinyl Alcohol with Acrylonitrile and Its Amidoxime Modification as a Heavy Metal Ion Adsorbent
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-10-26
    Lelin Zeng, Qian Liu, Wenyuan Xu, Guoxiang Wang, Yixue Xu, Enxiang Liang

    Abstract Polyvinyl alcohol (PVA) hydrogel was crosslinked with glutaraldehyde. The crosslinked polyvinyl alcohol (CPVA) was grafted with acrylonitrile using cericammonium nitrate as an initiator (CPVA-PAN), and then modified by hydroxylamine hydrochloride (CPVA-AO-PAN). CPVA, CPVA-PAN, and CPVA-AO-PAN were characterized by Fourier Transform Infrared spectroscopy. Cu2+ adsorption by CPVA-AO-PAN reached the equilibrium at contact time of 40 h with a adsorption capacity of 40.7 mg g−1. The effects of initial metal concentration, adsorption time, and pH on adsorption capacity were investigated, respectively. Pseudo-first-order and pseudo-second-order models were employed to evaluate the adsorption kinetics, with the R2 values of 0.9524 and 0.9972, respectively. Langmuir and Freundlich isotherm models were compared, and the Langmuir model shows high goodness-of-fit. The adsorption process was endothermic and spontaneous, as evidenced by the positive ∆H and the negative ∆G.

    更新日期:2020-01-09
  • Effect of Surface Functionalization of SiO 2 Nanoparticles on the Dynamic Mechanical, Thermal and Fire Properties of Wheat Straw/LDPE Composites
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-11-18
    Behzad Kord, Mohammad Dahmardeh Ghalehno, Farnaz Movahedi

    The scope of the present article is to study the effect of surface functionalization of SiO2 nanoparticles on the dynamic mechanical, thermal and fire properties of wheat straw flour (WSF) reinforced low-density polyethylene (LDPE) composites. Firstly, the SiO2 nanoparticles were modified by 3-aminopropyl-trimethoxysilane (APTMS), and then the WSF/LDPE composites containing different percentages of modified nano-SiO2 were prepared via a melt compounding using an internal mixer followed by injection molding. Changes in the chemical structure of treated SiO2 were tracked by Fourier transform infrared (FTIR). The appearance of N–H bond at 695 cm−1 and aliphatic C–H bonds at 2841 cm−1 and 2947 cm−1 were indications of successful grafting of APTMS on the SiO2 nanoparticles. Finally, the viscoelastic behavior, thermal stability and fire retardancy of the nanocomposites were evaluated by means of DMTA, TGA, DSC and CCT techniques. Results indicated that the dynamic modulus of the composites was greatly improved through the addition of functionalized SiO2 nanoparticles. In general, the specimens filled with 3 phr modified nano-SiO2 showed the highest values of storage and loss modulus compared with the other ones. Moreover, the tan δ peak signifying the glass transition temperature of nanocomposites shifted to higher temperature. The TGA results demonstrated that the introduction of APTMS grafted SiO2 nanoparticles can distinctly enhance thermal stability of the composites by increasing the thermo-oxidation decomposition temperature and char residues. The maximum activation energy value represents a higher thermal stability of the nanocomposites was obtained with modified nano-SiO2 at 5 phr content. In addition, the DSC data revealed that both the melting temperature and the degree of crystallinity of the specimens tended to substantially increase in presence of modified nano-SiO2. The surface functionalization of SiO2 particles produced remarkable evolution in the fire performance as indicated by reductions in the heat release rate, burning rate and mass loss rate. Furthermore, promoting the time to ignition and limiting oxygen index of the specimens equally to accommodate the addition of treated SiO2 nanoparticles.

    更新日期:2020-01-09
  • The Effect of Simultaneous Radical Polymerization of Poly( N -vinyl pyrrolidone)/α,ω-Bis(methacryloyloxy-poly(ethylene glycol)) on Physical Properties of Marine Polysaccharide
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-10-28
    D. Enescu, L. M. Pastrana

    In order to expand the application in biomedical field of bio-derived polymers it is imperative that the issues related to their surface properties be addressed. Here we explore the approach of simultaneous radical polymerization to modify the surface properties of chitosan by grafting/crosslinking with poly(N-vinyl pyrrolidone) (PNVP)/α,ω-bis (methacryloyloxy-poly(ethylene glycol) (M-PEG) in the presence of potassium persulfate. The structure of the resultant copolymer membranes was proved by Attenuated Total Reflectance-Fourier Transform Infrared Spectrometry. Scanning Electron Microscopy and Atomic Force Microscopy revealed the crosslinked copolymer membranes are porous materials with pore dimension, distribution and shape depending on the content of vinyl sequences. In addition, was revealed that the presence of vinyl crosslinked sequences linked to CS is disturbing the thermodynamic equilibrium conformation of CS. As a consequence, the ordering of CS chains into crystalline domains is reduced and the planes giving rise to the diffraction peaks are modified. Thus, the resultant copolymer membranes, depending by the weight ratio PNVP/M-PEG, became more amorphous. As a result of the crosslinking, the copolymer membranes were characterized by a smaller water swelling degree (about 300%) as compared with neat chitosan membrane (700%). The thermo-oxidative data have revealed an enhancement of the thermal stability of CS by crosslinking with PNVP/M-PEG copolymers. The water contact angles of the copolymer membranes proved to be more water wettable as compared to neat chitosan membrane.

    更新日期:2020-01-09
  • Development of Poly(lactic acid) Nanocomposites Reinforced with Hydrophobized Bacterial Cellulose
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-10-18
    Jhon Alejandro Ávila Ramírez, Jimena Bovi, Celina Bernal, María Inés Errea, María Laura Foresti

    Poly(lactic acid)/bacterial cellulose nanocomposites were prepared by solvent casting. Aiming to reduce the incompatibility between polar bacterial cellulose (BC) and the nonpolar poly(lactic acid) (PLA) matrix which induces filler aggregation and poor reinforcement dispersion, BC was acetylated by the use of a non-conventional route catalyzed by citric acid. The derivatized BC (AcBC) was incorporated into de PLA matrix at varying filler loadings, and optical, morphological, structural, thermal, tensile and barrier (water vapor) properties of PLA/AcBC in comparison with PLA/BC were evaluated. Noticeable changes in the nanocomposite properties were ascribed to the success of the route proposed to surface hydrophobize BC, which significantly improved its dispersibility within the PLA matrix and the matrix-filler interaction. By the way, the variation of filler loading allowed attaining remarkable increases in the nanocomposite films stiffness without significant reductions in tensile strength and water vapor permeability.

    更新日期:2020-01-09
  • Correlation Between Gel Strength of Starch-Based Hydrogel and Slow Release Behavior of Its Embedded Urea
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-06
    Xiaoqi Wei, Xianyang Bao, Long Yu, Hongsheng Liu, Kai Lu, Ling Chen, Lianyang Bai, Xiaomao Zhou, Zhuren Li, Wanming Li

    Starch-based hydrogels have attracted increasingly attention for application in controlled release fertilizers. However, there is currently a lack of knowledge on ways to characterize this system. In this work, we employed a hot-compression vulcanizer to in-situ synthesize monolithic urea-embedded grafted starch hydrogels with a slab geometry, which facilitates the subsequent measurement of gel strength and urea release kinetics. The results revealed that the greater the gel strength induced by a decreased urea load, an increased graft content, and an increased cross-linking density of starch-based hydrogels, the less the initial burst release of embedded urea. The unavoidable burst release could be ascribed to the heterogeneous network structure of starch-based hydrogels. The network of the hydrogels also afforded an zero-order, or at least time-independent, release kinetics of urea at intermediate stable stage, regardless of their microstructural parameters. Our results could provide a guideline to the design of hydrogel-based fertilizer delivery systems.

    更新日期:2020-01-06
  • Effect of the Addition of Citric Acid and Whey Protein Isolate in Canna indica L. Starch Films Obtained by Solvent Casting
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-06
    Liliana Ávila-Martín, Ángela A. Beltrán-Osuna, Jairo E. Perilla

    In this study, the effect of the addition of citric acid (CA) and whey protein isolate (WPI) on film properties of the starch extracted from the achira rhizome (Canna indica L.) was evaluated. For this purpose, starch films were prepared by solvent casting with different CA and WPI concentrations. Starch granules were fully characterized and the chemical and thermal behavior of the obtained starch films were also studied. The retrogradation phenomenon was analyzed in films from 1 week to 1 year of preparation. Maximum tensile strength (max) and maximum elongation at break (max), as well as water vapor permeability, were measured for all films. It was found that both molecules, CA and WPI, show a plasticizing effect on starch films, favoring the formation of a more uniform and resistant material by means of hydrogen bonding. A partial crosslinking between CA and starch was found by Fourier transform infrared, which is coherent with a higher degradation temperature peak found by thermogravimetric analysis. It was also observed that starch retrogradation was affected by the presence of both molecules, CA and WPI. The highest max (5.7 ± 0.1 N/mm2) and max (35%) values were achieved at the eighth weeks when both CA (6%) and WPI (11%) were used. Addition of CA and WPI did not show a significant difference in permeability values of starch films (1.40 × 10−9 ± 0.10 g/m s Pa).

    更新日期:2020-01-06
  • Towards the Production of mcl-PHA with Enriched Dominant Monomer Content: Process Development for the Sugarcane Biorefinery Context
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-02
    Guilherme H. D. Oliveira, Marcelo Zaiat, José Alberto D. Rodrigues, Juliana A. Ramsay, Bruce A. Ramsay

    The production of short-chain-length polyhydroxyalkanoates (scl-PHAs) in a sugarcane biorefinery setting has been demonstrated to be an effective strategy to reduce production costs. Medium-chain-length PHA (mcl-PHA) have elastomeric properties and are more suitable for high value-added applications, but its industrial production is not yet established. Mcl-PHA synthesis occurs via different metabolic routes and thus requires distinct microorganisms and substrates compared to scl-PHA. In the present study, sucrose-derived carbohydrates were evaluated as co-substrates for the production of mcl-PHA from decanoic acid (DA). Fermentation strategies were investigated to produce mcl-PHA with enriched dominant monomer content, which is desirable for commercial applications. The mcl-PHA production was investigated in carbon-limited, fed-batch fermentations with wild-type and β-oxidation knockout mutant strains of Pseudomonas putida KT2440. The experimental results demonstrated that a mixture of glucose and fructose was a suitable co-feed with DA for mcl-PHA production, yielding equivalent results to those obtained with starch-derived glucose, a more traditional feedstock for PHA production. The use of a β-oxidation-impaired strain was essential to attain high dominant monomer content. A near-homopolymeric mcl-PHA was produced under exponential feeding, containing 99 mol% of 3-hydroxydecanoate. This work demonstrates the potential for near-homopolymeric mcl-PHA production in a sugarcane biorefinery, using hydrolyzed sucrose and DA.

    更新日期:2020-01-02
  • New Spray-Dried Microcapsule Based on Brazilian Cashew Polysaccharide ( Anacardium othonianum Rizz.) and Maltodextrin as Wall Material
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-02
    Thâmara M. Silva, Leonardo L. Borges, Suzana F. Alves, Priscila D. S. Vaz, Luciano P. Silva, José R. de Paula, Maria T. F. Bara, Edemilson C. Conceição, Samantha S. Caramori

    Abstract The study describes the microencapsulation of Pterodon emarginatus fruit essential oil (OE) by spray drying using Brazilian Cerrado cashew polysaccharide (PEJU, Anacardium othonianum Rizz.) and maltodextrin (M) as wall materials. The microcapsules presented particles with irregular and rough surfaces confirmed by X-ray diffraction, with 57% in dry diameters ranging from 0 to 1 μm. Thermogravimetry showed a thermostable encapsulating material (peaks at 301 °C and 429 °C), with no loss of the encapsulated core. Zeta potential (ζ = − 0.18 mV) demonstrated the material’s amphiphilic power. The ratio of 1:3:3.6 of OE:cashew PEJU:M (w/w/w) showed the best encapsulation effect (75% yield and 6.25% of the OE retained) in the same proportion of β-caryophyllene retained. The Brazilian Cerrado cashew PEJU is a promising source for use as wall material in microcapsules, especially in protecting the OE of P. emarginatus fruits, as replacement for other gums, such as gum Arabic.

    更新日期:2020-01-02
  • Synthesis and Characterization of β-Cyclodextrin/poly(1-naphthylamine) Inclusion Complex and In-Vitro Release Studies of Metformin Hydrochloride
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-02
    Shabab Khan, Elham S. Aazam, Sapan Kumar Jain

    The present preliminary study reports the synthesis of β-cyclodextrin/poly(1-naphthylamine) (PNA) inclusion complexes at varying concentrations of 1-naphthylamine as monomer. The synthesized complexes were investigated for their spectral and morphological characteristics. IR studies confirmed that with the increase the loading of PNA, the hydrogen bonding interaction between NH of PNA and OH of β-cyclodextrin increased which was corroborated by the increase in the peak intensity corresponding to the OH stretching vibration of pristine β-cyclodextrin. UV studies confirmed the presence of higher number of quinoid units in PNA and tits interaction with β-cyclodextrin upon higher loading. The occurrence of phase transition during complex formation was confirmed by XRD analysis. Morphological studies highlighted the core–shell like morphology of the complexes. Metformin hydrochloride (MET-HCl) was chosen as a model drug to study the in-vitro drug release characteristics of these inclusion complexes. The validity of kinetic models for the adsorption of MET-HCl was studied using pseudo-first order model, pseudo-second order model, Elovich kinetic model and Intra-Particle Diffusion kinetic model and it was found that highest correlation coefficient was shown by pseudo-second-order model as well as by Elovich kinetic model. Hence the drug adsorption predominantly followed the pseudo-second order kinetics model. The drug release was investigated at gastric fluid (pH 1.2) and intestinal fluid (pH value 7.4) for a period of 1 h. The model with the highest correlation coefficient was confirmed to be of zero order and the value of n at gastrointestinal as well as intestinal fluids was calculated to be 1.2781 and 1.3262 respectively indicating super case-II transport mechanism.

    更新日期:2020-01-02
  • Recycling of Chrome Plated ABS Parts Pickled with Nitric Acid Free Solution
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-01
    Isabel Narloch Cardoso, Taise Ranzan, Ana Paula Kurek, Noeli Sellin

    Abstract One of the barriers to the recycling of chrome plated acrylonitrile–butadiene–styrene (ABS) is the degradation caused by the solution containing nitric acid used in the pickling of the metal layer. In this study, defective chrome plated ABS parts were pickled in a solution composed of lactic and sulfuric acids and hydrogen peroxide, and recycled by injection molding with different proportions of virgin ABS. The influence of pickled ABS on the chemical composition, thermal and mechanical properties of the samples was evaluated. The samples were chrome plated and characterized by visual inspection and adhesion tests. A slight yellowing of the virgin ABS/pickled ABS samples was observed due to the degradation of butadiene component. The thermal and mechanical properties were similar to those of virgin ABS. After the new chrome plating, all samples were approved in the adhesion tests, demonstrating that pickled ABS can be recycled by injection molding and chrome plating.

    更新日期:2020-01-02
  • Methodologies for Microplastics Recovery and Identification in Heterogeneous Solid Matrices: A Review
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-01
    Federica Ruggero, Riccardo Gori, Claudio Lubello

    Abstract The missing link in plastic mass balance between mismanaged plastic waste worldwide and plastic waste effectively detected in marine environments has recently risen the attention on microplastics. In fact, beside primary sources of microplastics such as cosmetic products and textile fires, there are secondary microplastics generated from plastic items due to weathering agents and biological degradation. While the marine and fresh water environments are actually of great concern, ground environments, and matrices related to it, have been less considered in the last years research about microplastics detection. Major attention should be reserved to solid heterogeneous matrices, such as soil, compost, sediments and sludges. Worldwide regulations about compost, which is used as amendant in agricultural fields, have a threshold ranging from 2 to 15 mm for the requirements related to plastic impurities. Microplastics which pass through the mesh of the threshold sieve are considered assimilable to compost. One of the main lacks that prevents the improvement of these regulation, is a standard protocol for microplastics detection in solid heterogeneous matrices. To this purpose, the current review proposes an outline of methods tested in previous research for microplastics recovery and identification in the matrices of our interest.

    更新日期:2020-01-01
  • Crystallization and Enzymatic Degradation of Maleic Acid-Grafted Poly(butylene adipate-co-terephthalate)/Organically Modified Layered Zinc Phenylphosphonate Nanocomposites
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-01
    Hsiang-Ting Wang, Erh-Chiang Chen, Tzong-Ming Wu

    Biodegradable nanocomposites were successfully synthesized using the maleic acid-grafted poly(butylene adipate-co-terephthalate) (g-PBAT) and organically modified layered zinc phenylphosphonate (m-PPZn), containing covalent linkages between g-PBAT and m-PPZn. Differential scanning calorimetry, wide-angle X-ray diffraction (WAXD), and transmission electron microscopy (TEM) were used to determine the crystallization behavior and morphology of g-PBAT/m-PPZn nanocomposites. The isothermal crystallization kinetics of g-PBAT/m-PPZn nanocomposites was determined using the Avrami equation. It was found that the half-time for the crystallization of the neat g-PBAT matrix is larger than that of g-PBAT/m-PPZn nanocomposites. This result suggests that the incorporation of m-PPZn can improve the crystallization rate of nanocomposites. The WAXD and TEM data illustrate that most of the m-PPZn layered materials are partially intercalated or exfoliated in the g-PBAT matrix. As the enzyme, lipase from Pseudomonas sp. was used for the enzymatic degradation tests. The degradation rates of the neatly fabricated g-PBAT copolymers using the heat pressing technique increase in the order of g-PBAT-80 > g-PBAT-50 > g-PBAT-20. The growing degradation rate of g-PBAT-80 is due to the growing amount of the adipate acid group and the increasing chain flexibility of the polymer backbone. Moreover, the increasing loading of m-PPZn enhances the weight loss of nanocomposites, suggesting that the existence of m-PPZn enhances the degradation of g-PBAT copolymers. The degradation rate of the freeze-drying samples containing a highly porous structure is greater than those prepared using the heat pressing technique.

    更新日期:2020-01-01
  • Solution Blow Spinning of Polylactic Acid to Prepare Fibrous Oil Adsorbents Through Morphology Optimization with Response Surface Methodology
    J. Polym. Environ. (IF 2.765) Pub Date : 2020-01-01
    Tingting Zhang, Hua Tian, Xueqiong Yin, Zhiming Li, Xiaohui Zhang, Jianxin Yang, Li Zhu

    Abstract Polylactic acid (PLA) fibrous membrane (PFM) was prepared through solution blow spinning (SBS). The effects of spinning parameters (solution concentration, gas pressure, and spinning distance) on the fiber diameter were studied by response surface methodology. The optimized preparation conditions of PFM were the concentration of PLA solution 8%, gas pressure 0.2 MPa, spinning distance 12 cm. Under the optimized conditions, the average diameter of PLA fibers was 770.45 nm. The oil saturated adsorption capacity of PFM to crude oil, peanut oil and diesel oil was up to 32.28 g/g, 28.80 g/g, and 19.50 g/g, respectively, while that of the commercialized nonwoven polypropylene was only 9.34 g/g, 9.17 g/g, 7.79 g/g, respectively. The adsorption capacity remained at about 50% of the saturated adsorption capacity after 10 cycles of reuse. Similar membrane was also successfully prepared from a waste PLA lid through SBS, which expressed similar oil adsorption behavior with PFM. SBS is potential to deal with the pollutions from waste oil and waste plastic.

    更新日期:2020-01-01
  • New Lignocellulosic Aristida adscensionis Fibers as Novel Reinforcement for Composite Materials: Extraction, Characterization and Weibull Distribution Analysis
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-24
    P. Manimaran, S. P. Saravanan, M. R. Sanjay, Mohammad Jawaid, Suchart Siengchin, Vincenzo Fiore

    In this research, the Aristida adscensionis fibers (AAFs) were taken out from the plants and its fundamental properties anlayzed for the first time. The AAFs were characterized and compared with other natural fibers by the use of physico-chemical analysis and various characterization techniques such as FT-IR, XRD, NMR, TGA, SEM and AFM. Chemical analysis showed that A. adscensionis fibers have a high cellulose content of 70.78% whereas the contents of lignin and wax are equal to 8.91% and 2.26%, respectively. The FT-IR, XRD and NMR analysis confirmed that AAFs are rich in cellulose content with CI and CS equal to 58.9% and 11.5 nm, respectively. Pycnometer analysis allowed to estimate a density of 790 kg/m3. The TGA revealed that these fibers are thermally stable up to 250 °C while SEM and AFM analysis evidenced that the fiber surface was rough. The fiber diameter and tensile properties was analysed by Weibull distribution. The characterization results and Weibull distribution analysis for the A. adscensionis fibers are an agreement with other natural fibers reported in literature. So this new lignocellulosic material is suitable as reinforcing phase in composites for potential engineering semi-structural applications like roofing sheets, bricks, door panels, furniture panels, interior paneling, storage tanks, pipelines, etc.

    更新日期:2019-12-25
  • Removal of Al(III) Ions Using Gellan Gum-Acrylic Acid Double Network Hydrogel
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-21
    Bengi Özkahraman, Zehra Özbaş

    Abstract The objectives of this research were to evolve a gellan gum based double network (DN) hydrogel with high mechanical properties, and investigate its potential as an adsorbent to remove Al(III) ion. The double network hydrogel was synthesized for the first time in the literature, and Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy were utilized for structural and morphological characterization. Gellan gum hydrogel was characterized in terms of mechanical strength. The Al(III) removal behaviour studies were performed in 100 ppm aqueous Al(III) solution, and the kinetic data were correlated with the models of pseudo-first order and second-order. In addition, the equilibrium adsorption data were applied to Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. Moreover, the DN hydrogel adsorption capacities were calculated for the regeneration and reuse studies. The DN hydrogel could be used at least five times without significant decreasing in its adsorption capacity. In this work, the possibility of the mechanically developed strong DN hydrogel was observed for Al(III) ion removal behaviour.

    更新日期:2019-12-22
  • A Recycling-Focused Assessment of the Oxidative Thermomechanical Degradation of HDPE Melt Containing Pro-oxidant
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-21
    Alex S. Babetto, Marcela C. Antunes, Sílvia H. P. Bettini, Baltus C. Bonse

    Abstract This study shows the effect of a pro-oxidant (oxo-biodegradable) additive on the oxidative thermomechanical degradation of high-density polyethylene (HDPE). It also allows us to predict the behavior of the material when subjected to mechanical recycling or to biodegradation. When HDPE, one of the most consumed thermoplastics worldwide, is transformed into a product or when subjected to primary and/or secondary recycling it will undergo thermomechanical degradation. According to current standards HDPE is not biodegradable, therefore pro-oxidants are added to many HDPE products, which can compromise the product's life. Knowledge on the influence of pro-oxidants on HDPE in the melt is limited and the objective of this study is to assess the behavior of HDPE containing pro-oxidant manganese stearate (MnSt) in the oxidative thermomechanical degradation process. Thermomechanical degradation tests were conducted in a closed-chamber torque rheometer. FTIR and SEC results agreed with those of torque rheometry and showed that oxidative thermomechanical degradation of HDPE increases with increasing manganese stearate concentration. Degradation resulted in an increase in the number of oxygenated functional groups, mainly ketones, aldehydes and carboxylic acids, and reduction in the weight-average molar mass of HDPE. MnSt may have acted both as a lubricant and pro-oxidant during processing with predominance of one or the other effect at different stages along the oxidative thermomechanical degradation of HDPE.

    更新日期:2019-12-21
  • Carboxymethyl and Nanofibrillated Cellulose as Additives on the Preparation of Chitosan Biocomposites: Their Influence Over Films Characteristics
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-20
    Talita Szlapak Franco, Rosa María Jiménez Amezcua, Adriana Villa Rodrìguez, Salvador García Enriquez, Maite Renteria Urquíza, Eduardo Mendizábal Mijares, Graciela Bolzon de Muniz

    Abstract The aim of this research was to prepare chitosan composite films with commercial carboxymethylcellulose (CMC) and nanofibrillated cellulose (CNF) from palmito sheaths pulp (agroindustrial discard) and compare their influence over the film’s properties. The morphology of cellulose additives influenced their interaction with the polymer matrix as verified on the FTIR spectra and on the SEM images, where the poor dispersibility of CMC could be visualized as aggregates and clusters on chitosan matrix. The extensive defibrillated particles of CNF were well dispersed mainly by their high number of hydrogen bridges that promoted an increase in crystallinity index even in the low level of addition (0.5%). Molecule interactions directly influenced the film’s mechanical properties, where the addition of 1.5% of CNF resulted in an increment of 1.300% for Young’s modulus and 280% for tensile strength; a reduction of 20% of UV light transmittance and a decrease of almost 50% on water absorption. By the other side, even with an increase on the crystallinity index, the addition of CMC resulted in films with low mechanical and barrier properties as compared to the control film. The addition of nanocellulose overcame chitosan main weakness and leaded to a total renewable, biodegradable nanocomposite with adequate mechanical and physical properties to be applied on package development and with the extra attractive of being obtained from an agroindustrial residue, contributing with sustainability and environmental safety concerns.

    更新日期:2019-12-21
  • Aqueous Solution of a Basic Ionic Liquid: A Perspective Solvent for Extraction and Regeneration of Silk Powder from Bombyx mori Silk Cocoons
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-17
    Muhammad Samie, Nawshad Muhammad, Muhammad Arfat Yameen, Aqif Anwar Chaudhry, Hamad Khalid, Ather Farooq Khan

    The rationale behind this study was to investigate the potential new low cost and biocompatible aqueous choline based ionic liquid for dissolution and regeneration of silk fibroin obtained from the mulberry silkworm. The silk due to its high biocompatibility and mechanical properties finds many applications in the field of biomedical science. Earlier, silk extraction methods have issues of either extraction efficiency or environmental concerns. The ionic liquid is a relatively green solvent was used to dissolve silk fibroin and optimized the process with respect to variables like temperature, time, stirring speed, type of ionic liquid and maximum dissolution ability. The dissolution process was observed through the naked eye as well as using optical microscopy. The optimized conditions at which maximum dissolution i.e. 25% was obtained, are heating the mixture at 50 °C for 2 h. Various analytical characterization such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), Zeta potential, nuclear magnetic resonance (1H NMR) and thermogravimetric analysis (TGA) was performed for cocoon, fiber and regenerated silk powder in order to understand the effect of ionic liquid treatment. FTIR, NMR and Raman spectra shows the characteristic peaks assigned to the silk. SEM analysis shows nanoparticles of silk fibroin powder. The crystallinity and thermal stabilities were decreased for regenerated silk as observed from XRD and TGA analysis. The nano-silk exhibited a zeta potential of − 24.6 ± 3 mV.

    更新日期:2019-12-18
  • Effect of Heat-Treatment on Self-healing and Processing Behavior of Thermally Reversible Polyurethanes
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-14
    Libang Feng, Yaohui Bian, Changsheng Chai, Xiaohu Qiang

    Given its thermal reversibility, high yield, and minimal side reactions, the Diels–Alder (DA) reaction is a particularly desirable technique for the preparation of polymeric materials with heat-stimulated self-healing properties. A linear self-healing polyurethane containing thermally reversible DA bonds (PU-DA) was developed in this study. Results revealed that the introduction of DA bonds conferred outstanding mechanical property and thermal reversibility to PU-DA films. Thus, the as-prepared PU-DA films demonstrated excellent self-healing performance. The self-healing behavior of the PU-DA films under various heat treatments was examined through qualitative observation and quantitative measurements. The PU-DA underwent self-repair through the combination of two healing actions, i.e., the thermal movement of molecular chains and the thermally reversible DA reaction. Moreover, the self-healing behavior of the PU-DA was repeatable, and the PU-DA continued to present high strength even after undergoing three damage–repair cycles at the same site. In addition, the as-prepared PU-DA exhibited excellent macro-scale self-healing behavior, and it endowed the PU-DA presented reprocessing performance. The PU-DA can be recycled given its excellent self-healing and outstanding reprocessing performances.

    更新日期:2019-12-17
  • Physical, Mechanical, Structural and Antibacterial Properties of Polyvinyl Alcohol/Oregano Oil/Graphene Oxide Composite Films
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-13
    Derong Lin, Zhijun Wu, Yichen Huang, Jingjing Wu, Chunxiao Li, Wen Qin, Dingtao Wu, Suqing Li, Hong Chen, Qing Zhang

    Polyvinyl alcohol/oregano oil/graphene oxide antibacterial composite film was prepared from PVA and GO by adding OEO as the antibacterial agent. The effect of different OEO contents on the properties of the composite film was studied. The results showed that the OEO improved the performance of the composite film. With the increase of OEO content, the thicknesses were increased, the mechanical properties were improved, and the antibacterial activities were increased. The performances of the film with 1% OEO were the best. The tensile fracture elongation and the tensile strength were 249% and 20.760 MPa, respestively. The diameter of the antibacterial ring of E. coli and L. monocytogenes was 11.70 mm and 12.61 mm, respectively. FTIR revealed that there were chemical bonds among PVA, GO and OEO. SEM showed that OEO made the surface of the composite film smoother. TGA showed that OEO did not affect the coke yield of composite films. DSC indicated that OEO reduced the exothermicity of composite films. The antibacterial properties of natural essential oils were taken advantage of to make the antibacterial composite films, which was beneficial to expand the use of essential oils in packaging films, and provides a reliable reference for other researchers.

    更新日期:2019-12-13
  • Removal and Preconcentration of Pb(II) Heavy Metal Ion from Water and Waste-Water Samples onto Poly (vinyl alcohol)/polyethyleneimine/Fe 3 O 4 Microfibers Nanocomposite
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-11
    Elnaz Bavel, Abbas Afkhami, Tayebeh Madrakian

    In this research, poly (vinyl alcohol)/polyethyleneimine/Fe3O4 (PVA/PEI/Fe3O4) microfibers nanocomposite was synthesized in order to remove and/or preconcentrate Pb(II) ions. The microfibers nanocomposite was characterized by FT-IR, SEM, and XRD methods. The effects of various parameters such as pH, amount of adsorbent, and contact time on the adsorption efficiency of Pb(II) ions at the adsorbent were fully investigated and the optimum conditions were established. The adsorption capacity was found to be 370.9 mg g− 1 of the adsorbent. The kinetics of metal ions adsorption was evaluated using pseudo-first-order and pseudo-second-order models. The results showed that the adsorption of the investigated metal ion is in agreement with the pseudo first-order kinetics. The adsorption–desorption process was conducted for five cycles and the removal efficiency still kept 97% after three cycles.

    更新日期:2019-12-11
  • Hybrid Crosslinked Chitosan-Epichlorohydrin/TiO 2 Nanocomposite for Reactive Red 120 Dye Adsorption: Kinetic, Isotherm, Thermodynamic, and Mechanism Study
    J. Polym. Environ. (IF 2.765) Pub Date : 2019-12-11
    Ali H. Jawad, Nur Shazwani Abdul Mubarak, Ahmed Saud Abdulhameed

    Hybrid crosslinked chitosan-epichlorohydrin/TiO2 nanocomposite (CTS-ECH/TNC) was synthesized as an inorganic–organic hybrid nanocomposite bioadsorbent for the removal of reactive red 120 (RR120) dye from aqueous environment. Various analytical techniques were utilized to investigate the surface area, surface morphology, martial crystallinity, elemental composition, amino group content, and fundamental functional group of CTS-ECH/TNC. The impact of key adsorption parameters such as adsorbent dosage (0.02–1.2 g), initial RR120 dye concentration (30–400 mg/L), solution pH (3–12), contact time (0–300 min), and temperature (303–323 K) were explored by batch adsorption process. The adsorption data were well illustrated by pseudo-second order (PSO) kinetic and Langmuir isotherm model. The adsorption process was also found to be a spontaneous and endothermic in nature as indicated by thermodynamic study. The maximum adsorption capacity of CTS-ECH/TNC for RR120 dye was recorded to be 210 mg/g at 303 K. Various types of interactions such as electrostatic attraction, n-π stacking, and H-bonding were responsible for adsorbing RR120 dye molecules on the surface of CTS-ECH/TNC as investigated by tailored adsorption mechanism. Thus, this work introduces CTS-ECH/TNC as promising hybrid biosorbent for the removal of RR120 dye as model of reactive azo dyes from aqueous environment.

    更新日期:2019-12-11
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