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  • Effects of some material parameters on lignin biopolymer liquefaction by microwave heating
    Iran. Polym. J. (IF 1.707) Pub Date : 2020-01-20
    Raziye Mohammadpour, Gity Mir Mohamad Sadeghi

    Abstract A kraft lignin was liquefied in solution reagents such as polyethylene glycol (PEG) and glycerol under microwave heating. The effects of glycerol concentration, molecular weight of PEG and lignin mass were investigated on lignin liquefaction process through microwave irradiation. For this purpose, the prepared polyols were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance and carbon-13 nuclear magnetic resonance techniques. Further, the hydroxyl value (OHV) of polyols was determined by titration method. The results indicated that addition of glycerol increased liquefaction yield and OHV of polyols due to its role as co-solvent in liquefaction process and as a microwave absorber. Glycerol could be used up to 30 wt%, though the beneficial amount of glycerol was obtained as 20 wt%. In another run, it was observed that PEG with a molecular weight of 400 g/mol was an efficient solvent in liquefaction process, which introduced the highest amount of OHV in lignin polyol. A study on the effect of lignin mass was carried out with sufficient amount of glycerol and PEG400 as liquefaction reagents. The results revealed that with further increase in lignin/solvent weight ratio, the molecular weight of polyol increased while its OHV was reduced. Therefore, there was a limiting range in addition of lignin due to insufficient liquefaction solvent in causing enhanced condensation reaction during the liquefaction process. Finally, the polyol with sufficient amounts of testing components was nominated as an optimal polyol with the highest OHV (630 mg KOH/g) and suitable liquefaction yield.

    更新日期:2020-01-21
  • Photochromic microcapsules by coacervation and in situ polymerization methods for product-marking applications
    Iran. Polym. J. (IF 1.707) Pub Date : 2020-01-18
    Ozlem Topbas, Ayse Merih Sariisik, Gokhan Erkan, Orhun Ek

    Abstract Photochromic materials can change their colour quickly and reversibly when exposed to light of certain wavelengths. These materials have recently been of great interest for intelligent and functional textile applications. In this study, two different photochromic dyes, including 1′,3′-dihydro-1′,3′,3′-trimethyl-6-nitro-spiro[2H-1-benzopyran-2,2′-(2H)-indole] and 1′,3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole], were microencapsulated by coacervation and in situ polymerization methods. Ethyl cellulose and melamine–urea–formaldehyde were used as polymers. The Fourier transform infrared spectroscopy, particle size and size distribution analysis, scanning electron microscopy, and ultraviolet spectrophotometry evaluations were utilized to characterize the structure, morphology, size distribution, and absorbance maxima of the photochromic microcapsules. The results indicated that photochromic microcapsules were in spherical shape, smooth, and homogeneous characteristics. These microcapsules were applied successfully onto cotton fabric using printing technique. Then, the activities of photochromic microcapsules on the fabrics were analysed by colour analysis under different light sources, fatigue resistance, washing, and rubbing fastness tests. After printing, the colours of the fabrics changed very quickly under different light sources. At the same time, these fabrics showed a reversible photochromic response and good fatigue resistance. Mechanical and physical properties of the fabrics such as thickness, air permeability and tensile and tear strength were also investigated. It can be concluded that photochromic microcapsules are well appropriate for brand protection and prevention of imitation in textile materials.

    更新日期:2020-01-21
  • Effect of tensile action on retrogradation of thermoplastic cassava starch/nanosilica composite
    Iran. Polym. J. (IF 1.707) Pub Date : 2020-01-17
    Yuxin Liu, Lilan Fan, Jinying Pang, Dengfeng Tan

    Thermoplastic cassava starch (TPS)/nanosilica (SiO2) composite was prepared by melt mixing, and the effect of tensile action (stress) on the structures and properties of TPS/SiO2 composite during the retrogradation stages was investigated. Differential scanning calorimetry (DSC) analysis indicated that the retrogradation enthalpy of TPS/SiO2 composite with the tensile action was higher than that of the composite without the tensile action after short retrogradation time. Thermogravimetric analysis (TG) displayed that the decomposition temperature and activation energy of thermal degradation of the composite under the tensile action were higher than those of composites without the tensile action. The contact angle and tensile strength of TPS/SiO2 composite with the tension action became larger after the tension stress was applied during the short retrogradation time. From the Fourier transform infrared (FTIR) spectroscopy results, the stretching vibration of the hydroxyl group enhanced with the increase in retrogradation time. According to the polarized light microscopy (PLM) analysis, the composite samples showed Maltese cross-pattern, and it became blurred after the tensile stress was exerted on the samples. With the increase in retrogradation time, the inter-planner spacing decreased and crystal size of TPS/SiO2 composite increased. The tensile action could weaken the A-type and promote the formation of the V-type crystalline structure. The scanning electron microscopy (SEM) results showed that the fracture surface of composite sample without the tensile action was smooth, and the granular structure of starch could not be clearly seen, however, the fracture surface of composite under the tensile action was rough, and the granular structure of starch was clear.

    更新日期:2020-01-17
  • Improvement in phase-change hybrid nanocomposites material based on polyethylene glycol/epoxy/graphene for thermal protection systems
    Iran. Polym. J. (IF 1.707) Pub Date : 2020-01-11
    Samire Sabagh, Ahmad Reza Bahramian, Majid Haghir Madadi

    Abstract Polyethylene glycol (PEG) is established as an organic solid–liquid phase-change material (PCM) offering a wide range of enthalpies and phase transition temperatures as a function of its molecular weight. PCMs are known for their high-energy absorbance; however, they also have two main drawbacks of leakage and enthalpy reduction during melting. In this work, polyethylene glycol as a phase-change material and graphene oxide (GO), expanded graphene (EG), and epoxy resin (EP) as shape stabilizing materials were used and designed based on experimental design—Taguchi method to find the composition with the least molten PEG leakage and the highest enthalpy of melting. Based on improvements made on main drawbacks, two samples were introduced, while their only difference was epoxy content. The results showed that the epoxy resin and graphene oxide caused a significant reduction in molten PEG leakage by hydrogen bonding and trapping of PEG between GO plates and the barrier effect. Also, the expanded graphene by heterogeneous nucleation of molten PEG in a cooling cycle caused a dramatic increment in crystallinity and enthalpy of melting. Among the achievements of this research is the attainment of hybrid nanocomposites samples without leakage (less than 5 wt%) and samples with enthalpy of melting more than that of pure polyethylene glycol (8%).

    更新日期:2020-01-13
  • Isothermal cold crystallization kinetics and properties of thermoformed poly(lactic acid) composites: effects of talc, calcium carbonate, cassava starch and silane coupling agents
    Iran. Polym. J. (IF 1.707) Pub Date : 2020-01-10
    Chutimar Deetuam, Chavakorn Samthong, Suphattra Choksriwichit, Anongnat Somwangthanaroj

    Abstract The effects of three different fillers (i.e., talc, calcium carbonate, and cassava starch) and surface functionalization by 3-aminopropyltriethoxysilane (APTES) and vinyltriethoxysilane (VTES) on morphology, thermal and tensile properties of the poly(lactic acid) (PLA) composites were comparatively examined. Dynamic differential scanning calorimetry (DSC) results revealed that the incorporation of filler can facilitate the cold crystallization of PLA, as confirmed by lowered cold crystallization temperature. By fitting DSC data with Avrami model, the highest isothermal cold crystallization rate constant k and the shortest crystallization half time t1/2 were obtained for the PLA/talc composites under isothermal temperature of 100 °C, implying that talc was the most effective nucleating agent for PLA in this study. The average Avrami index n of neat PLA and its composites lay within the same range of 3.0–3.6, which reflected the three-dimensional spherulitic growth of PLA with the mixture of instantaneous nuclei and sporadic nuclei. In comparison with the composite cast films, the thermoformed films had higher degree of crystallinity as well as higher tensile strength and Young’s modulus owing to the chain orientation upon annealing. Furthermore, the addition of silane-treated talc, especially APTES-treated talc, fastened cold crystallization rate and enhanced tensile properties because of the improved interfacial interaction between talc particles and PLA matrix.

    更新日期:2020-01-11
  • Sol–gel based layer-by-layer deposits of lanthanum cerium molybdate nanocontainers and their anticorrosive attributes
    Iran. Polym. J. (IF 1.707) Pub Date : 2020-01-09
    Sakshi Arora, Siddhesh Mestry, Hitesh Kumar Singh, Shashank T. Mhaske

    Abstract The present study focuses on the synthesis of novel lanthanum cerium molybdate (LCM) nanoparticles by sol–gel synthesis method and their use in the development of nanocontainers in an anticorrosive coating application. The obtained nanoparticles were used as core material with two different polyelectrolytic shells comprising of polypyrrole (PPY) and polyacrylic acid (PAA) or polyethyleneimine (PEI) and polystyrene sulfonate (PSS) involving the entrapment of benzotriazole (BTA) as the corrosion inhibitor using layer-by-layer (LBL) deposition method. At each step of this nanocontainer synthesis, the thickness of the layers, surface charges and the presence of the functional groups were determined by particle size, zeta potential and Fourier transform infrared spectroscopy (FTIR) analysis, respectively. The X-ray diffractograms (XRD) indicated the change in the crystallinity of the nanoparticles and nanocontainers while thermogravimetric analysis (TGA) showed the thermal degradation behavior of the nanocontainers. The morphological studies conducted using scanning electron microscopy (SEM) exhibited the formation of nanocontainers containing nanoparticles in their cores. The release of BTA from the nanocontainers was evaluated at different pH values. The anticorrosive performance of the nanocontainers was examined by incorporation of the nanoparticles and nanocontainers in a commercial epoxy coating system and to be applied on mild steel and magnesium panels by electrochemical corrosion analysis. Tafel plots demonstrated the decrease in the current density with an increase in the loading percentage of nanocontainers in the epoxy system while Bode plots confirmed the significant improvement in the corrosion protection of the mild steel and magnesium by LCM nanoparticles and nanocontainers.

    更新日期:2020-01-09
  • New electroactive and photosensitive polyamide/ternary LDH nanocomposite containing triphenylamine moieties in its backbone: synthesis and characterization
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-12-21
    Nematollah Basaki, Ali Kakanejadifard, Khalil Faghihi

    Abstract The new ternary (Mg–Zn–Al–) layered double hydroxide (LDH) with an organic modifier-containing azo group (LDH–SHDBS) as a guest anion was prepared by a co-precipitation through one-step synthetic method. The novel electroactive polyamide (EPA) was successfully prepared by direct polycondensation reaction of azelaic acid with a new synthetic diamine 4. The structure of diamine 4 was confirmed by FTIR and 1H NMR spectra. Also, polyamide/ternary LDH nanocomposites were prepared by resulting EPA and modified ternary LDH under ambient condition. The resulting data using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) showed ternary LDH were successfully distributed into the EPA matrix. Thermal behavior of the EPA and its nanocomposites were studied by thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG). The presence of LDH layers into EPA matrix improved thermal stability (T5, T10, char yield) in both air and nitrogen atmospheres. Also, photoisomerization and electrochemical behaviors of EPA and resulting nanocomposites were measured using UV–Vis spectroscopy and cyclic voltammetry (CV), respectively. The UV–Vis spectrum of the obtained nanocomposites showed two peaks at λmax = 422 and 480 nm related to π–π∗ and n–π∗ transitions of trans azobenzene. Moreover, trans to cis isomerization of azomoieties was studied by irradiation of the nanocomposites under 254 nm photons. The CV pattern of EPA exhibited a reversible anodic peak around 0.84 V, corresponding to the nitrogen atom of triphenylamine unit into polymer backbone that improved by incorporation of LDH–SHDBS into EPA matrix.

    更新日期:2019-12-22
  • Curing kinetics, thermal and adhesive properties of phthalonitrile/aromatic diamine systems
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-12-16
    Caizhao Liu, Mingming Sun, Bin Zhang, Xugang Zhang, Gang Xue, Xiwen Zhang

    The present work reports on the synthesis of an easily processable phthalonitrile monomer (BBPN) with isobutyl segment. The effect of various curing agents on curing behaviors, thermal and adhesive properties of BBPN has been evaluated. The novel phthalonitrile monomer was synthesized through nucleophilic substitution of 2,2-bis(4-hydroxyphenyl)butane (BPB) and 4-nitrophthalonitrile, and its chemical structure was characterized with FTIR, 1H NMR and 13C NMR analyses. Four different aromatic diamines derived from different catalytic activities such as p-phenylenediamine (p-PD), m-tolidine (m-TB), o-tolidine (o-TB), and 2,2′-bis(trifluoromethyl)benzidine (TFMB) were used as curing agents. The curing kinetics of BBPN/aromatic diamine samples were investigated by non-isothermal differential scanning calorimetry (DSC) at different heating rates. The average activation energy was calculated based on Kissinger’s and Ozawa’s methods varied in the range of 66.61–79.00 kJ mol−1. The thermal properties of the obtained polymers were investigated by dynamic mechanical thermal analysis (DMA) and thermogravimetric analysis (TGA). Compared to other three systems, the cured BBPN/p-PD exhibited better thermal stability and higher glass-transition temperature (Tg), suggesting its higher degree of cross-linking. Moreover, the BBPN/diamine systems were used to bond aluminum sheet, and the average values of lap shear strengths were in the range of 13.8–19.6 MPa at room temperature and 9.2–11.5 MPa at 300 °C, respectively.

    更新日期:2019-12-17
  • Electrospun polyvinylidene fluoride/polyacrylonitrile composite fibers: fabrication and characterization
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-12-04
    Guizhen Ke, Xinya Jin, Haoxuan Hu

    The purpose of this study is to make use of the advantages of both polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN) to fabricate a flexible electronic device. Polyvinylidene fluoride (PVDF)/polyacrylonitrile (PAN) composite fibrous mats with different blend ratios were fabricated using electrospinning. The effects of PVDF and PAN mass ratio on fiber morphology, chemical structure, thermal stability, and piezoelectric properties of the produced composite fibers were investigated by scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), and piezoelectric tester. The SEM images showed that the PVDF/PAN composite nanofibers were fabricated successfully and fiber diameters increased with the increase of PVDF content. The FTIR and XRD analyses showed that both the α- and β-crystal phases existed in PVDF/PAN composite fibers. The thermal stability of PVDF/PAN fibrous mats was less than that of neat PVDF fibers. The piezoelectric properties of PVDF/PAN fibrous mats were significant and a function of PVDF content. The output voltage of PVDF/PAN fibrous mats increased from 1.2 to 5.0 V as PVDF content increased from 20 to 100%. The piezoelectric voltages of PVDF/PAN composite nanofibers also increased with the increase of impacting force. Tensile and contact angle testing indicated that the PVDF/PAN fibrous mats were more flexible and hydrophilic than neat PVDF membrane. PVDF/PAN nanocomposite fiber mats were observed suitable for potential application in flexible electronic devices.

    更新日期:2019-12-11
  • Tough and translucent hydrogel electrode for electrochemical cleaning of paper artworks
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-05
    Xingtang Liang, Changling Lei, Zijie Liu, Shuming Zhong, Ruirui Zhang, Yunying Zheng, Yanzhen Yin, Shufei Jiao, Daodao Hu

    Due to the favorable retention power and viscosity, the hydrogel that is loaded with an aqueous detergent, represents a promising cleaning tool for removing the foreign matters such as polymer adhesive, starch paste, and animal glue from paper artworks. However, it is still challenging to eliminate other stains, including organic dyes, commercial drinks, foxing, and mildew. Herein, we present an alternative methodology, translucent hydrogel-containing electrolyte-based electrochemical cleaning (EC), which incorporates electrochemical reactions into the hydrogel-based cleaning process using the extremely tough and translucent alginate/polyacrylamide hydrogel as cathode and PbO2 as anode. The proposed approach is generally applicable to eliminate different stains such as organic dyes, commercial drinks, mildew, and foxing from paper under several mA/cm2 and a few minutes in a small controlled area. For the excellent mechanical strength, the hydrogel electrode can be reused for several times without losing its efficiency and easily peeled-off from paper as one body without any gel residues after cleaning. We further demonstrate the effect of EC on the treated paper, including the morphology, degree of polymerization, crystal structure, and mechanical properties. We conclude that the influence of EC on the paper is slight under the mild treatment.

    更新日期:2019-12-11
  • Preformed particle gels of sulfonated polyacrylamide: preparation, characterization, and application as permeability modifier
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-01
    Aghdas Heidari, Ebrahim Vasheghani-Farahani, Mohsen Vafaie-Sefti

    In this study, a preformed particle gel (PPG) was synthesized from sulfonated polyacrylamide and chromium metal cross-linker with specific concentration. The main characteristics of PPG, such as gelation time, gel fraction, swelling properties and salt sensitivity factor were investigated. The gel fraction of 94.1% practically indicated an appropriate conversion of gelant to the gel. The equilibrium swelling ratios of particle gels in distilled water and formation water at 80 °C were 470.49 and 12.61, respectively. Additionally, the rheological properties of gel were studied by a dynamic rheometer. The ultimate storage modulus of gel was measured 35.4 kPa. The linear viscoelastic behavior was observed at strain between 1 and 82.6% and gel structure was stable up to strain of 1120% with small reduction of storage modulus. The kinetics of gelation were also studied at different temperatures and tested against Avrami equation to determine the kinetic parameters. The Avrami exponents for two kinetic steps were about 2.29 and 0.80, respectively, indicating the rapid formation of the gel network at first step due to nucleation and two-dimensional growths of gel nuclei. Furthermore, a core flooding experiment was conducted to study PPG performance in porous media. The residual resistance factor of water and oil was 41.58 and 12.91, respectively. A value of 3.22 for the ratio of these two factors indicated the ability of the synthesized PPG to decrease water-effective permeability compared to oil-effective permeability in porous media.

    更新日期:2019-12-11
  • Styrene butadiene rubber/epoxidized natural rubber/carbon filler nanocomposites: microstructural development and cure characterization
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-10-29
    Sara Khalifeh, Mitra Tavakoli

    Microstructural development of elastomeric nanocomposites based on (50/50 wt%) styrene butadiene rubber (SBR) and epoxidized natural rubber (50 mol% epoxidation, ENR50) as the rubber matrix including two types of carbon fillers, carbon black (CB) and functionalized multiwall carbon nanotube (NH2-MWCNT), which were prepared through melt mixing, was studied. The results from FTIR analysis show that there is interaction between functional groups on MWCNT surface and the rubber chains. The AFM analysis also indicates good dispersion of filler particles in the rubber phases. FESEM images from cryo-fractured surface of samples have revealed that nanotubes were rarely pulled out of matrix and their diameter increased, resulting from good interaction between MWCNTs and rubber chains. The DMA results confirm good interfacial interaction between them. Furthermore, the reduced difference between the two Tgs of phases (ΔTg) shows that the incorporation of 3 phr MWCNT into the blend leads to increment in rubber phase compatibility but at higher MWCNT content (5 phr) due to lower Mooney viscosity of SBR phase, MWCNTs tend to remain in this phase. The bound rubber was adopted to characterize the polymer–filler interaction, showing that bound rubber content has an increasing trend with increasing in fillers content. The cure rheometric studies reveal that MWCNTs accelerate the cure process due to the presence of amine groups on the nanotube surface. In addition, the mechanical properties of samples show an increasing trend by increasing nano-filler content.

    更新日期:2019-12-11
  • Investigation of degradation of polypropylene in soil using an enzymatic additive
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-06
    Jéssica Pereira Pires, Gabriela Messias Miranda, Gabriela Lagranha de Souza, Flávia Fraga, Alessandro da Silva Ramos, Gabriel Espindola de Araújo, Rosane Angélica Ligabue, Carla Maria Nunes Azevedo, Rogerio Vescia Lourega, Jeane Estela Ayres de Lima

    Polypropylene (PP) has been widely used industrially in several sectors, mainly in the use of packaging of different products. Thus, this has been accumulated in our environment due to the incorrect disposal and its high resistance toward degradation, causing an array of environmental impacts. With this, one alternative that has been explored to minimize the problems intensified by these residues is the use of pro-degrading additives. Therefore, the aim of this work is to evaluate the degradation process of PP blends in soil using enzymatic additive. The soil degradation experiment was done for 6 months; monthly collected samples were checked for alterations on the material properties during that time. The extent of PP degradation with enzymatic additive was compared to an organic additive by techniques of FTIR, TGA, DSC, carbonyl index (CI), and crystallinity. From the obtained results it was observed that the additives influenced the degradation of PP. In addition, the enzymatic additive caused more significant changes in the CI (increase of 3693%), crystallinity (variation of 18.7%), and structural characteristics, indicating a greater influence on the degradation process in relation to the organic additive. In this way, this work has had an important role in the research and development of biodegradable materials with the aim of minimizing the effects induced by plastic waste in the environment.

    更新日期:2019-12-11
  • Understanding the effect of chain extender on poly(butylene adipate- co -terephthalate) structure
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-06
    Alana Gabrieli de Souza, Edilene de Cássia Dutra Nunes, Derval dos Santos Rosa

    We investigated poly(butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer, under the influence of a chain extender (a multifunctional epoxide oligomer, Joncryl ADR-4370S®, ADR) at different concentrations, and correlated their properties concerning the molecular interaction between the active sites of the structures. Several studies have used ADR in poly(lactic acid)-PBAT blends; however, the effect of ADR in terms of chemical and physical interaction with PBAT is not investigated in-depth, which can limit its applications. The chain extender is usually applied to improve the mechanical and thermal properties and PBAT resistance to thermal degradation. The developed materials were evaluated by high-resolution solid-state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), mechanical and thermal properties, and rheological measurements. NMR and FTIR indicate an interaction between the carboxylic sites of PBAT and the epoxy sites of ADR. PBAT-2%ADR shows higher tensile properties, probably due to the hydrogen bonds and interactions of π–π nature between the materials; in this case, the ADR can act as a reinforcing agent. High contents of chain extender can change the nature of the interaction and influence the final properties of the polymer. The effect of this additive was found to be strongly dependent on the content used and the polymer processing. It was observed that ADR could act as an internal lubricant during processing (due to the low molecular weight of this additive), demonstrating the importance of processing parameters control.

    更新日期:2019-12-11
  • Tailoring structural, morphological and mechanical characteristics of mono-crystalline diamond-reinforced polyacrylonitrile based electrospun fibers
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-11
    Mohib Ullah, Saifur Rehman, Luqman Ali Shah, Mohammad Siddiq

    Composites of diamond-reinforced particles offer extraordinary thermal- and mechanical characteristics attributable to their manageable outer surface and huge available uppermost layer. Uniform distribution of diamond powder in polymeric matrix, and enhanced interactions between them are the two significant problems to attain robust polymer composites. In this work, the crystalline diamond particles as received and chemically modified ones were integrated in polyacrylonitrile (PAN) matrix uniformly by electrospinning method. This procedure avoided agglomeration of the reinforced diamonds through uniform distribution in the polymer matrix. The shapes of diamond-integrated PAN fibers were attuned by adapting diamond loading, polymer concentration, flow rate, and applied voltage to achieve beads free fibrous structures. PAN was chosen as a carrier polymeric-matrix to enhance the electrostatic forces between functionalized diamond-particles and PAN molecular chains. Tensile tests showed that the loading of 2 wt% modified diamond-particles improved Young’s modulus of fibers by 74.94% and tensile strength by 125%. Therefore, modification of the outer surface of the diamond particles improved the chemical interactions between the diamond surface and matrix, and stress was transferred to the diamond particles in composite fibers. Additionally, thermal stabilities of the diamond-based polymer composites were enhanced by the integration of diamond powder in composite fibers.

    更新日期:2019-12-11
  • Poly(itaconic acid)-assisted ultrafiltration of heavy metal ions’ removal from wastewater
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-09
    Hamidreza Rezania, Vahid Vatanpour, Somayeh Faghani

    The complexation–ultrafiltration technique has been introduced as a capable system to remove heavy metals ions from wastewater. This method needs a water-soluble polymer; therefore, in this paper we synthesized super water-soluble poly(itaconic acid) (PITA) and employed it in polymer-assisted ultrafiltration process to remove Pb(II) ions from synthetic wastewater solutions. The itaconic acid can be produced from different agricultural products and is a green and eco-friendly material. Factors influencing the removal of the metals ions including poly(itaconic acid) concentration, pH and permeate flux were investigated. The results showed that the maximum percentage of metal ion removal was obtained in the basic pH (pH > 7). The flux test was performed by 200 mg/L of poly(itaconic acid) and after 60 min, the flux of membrane was 33.4 L/m2h. The simultaneously selective removal ability of the poly(itaconic acid) for adsorption of different metal ions (Pb2+, Sn2+, Cu2+, Zn2+, and Cd2+) was also studied. The trend of rejection was Pb2+ > Cu2+ > Sn2+ > Zn2+ > Cd2+. The highest rejection of Pb(II) ions was achieved as 86%. Generally, the results of this research demonstrated that poly(itaconic acid) (with two carboxyl groups on its repeating unit) is more effective in removing heavy metals ions from wastewater in comparison with customary polymers.

    更新日期:2019-12-11
  • Enhanced performance of urea–glyoxal polymer with oxidized cassava starch as wood adhesive
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-05
    Hui Wang, Feng Wang, Guanben Du

    To eliminate the hazard of formaldehyde from wood-based products to human and environment, formaldehyde was replaced by glyoxal to produce wood adhesive. Urea–glyoxal (UG) resin was environmental friendly, while its bonding strength was very poor, especially its water resistance. The object of this work was to improve the mechanical properties of UG resin by oxidized cassava starch addition. Hence, the urea–glyoxal (UG) resin was synthesized and the oxidized cassava starch was added through mechanical mixing. The bonding strength, structure distributions, and the morphology features of the cured UG resin system were investigated by producing a three-layer plywood, FTIR, and SEM analysis. The results of dry and wet shear strength of plywood indicated that there was a positive effect of oxidized cassava starch on bonding strength of a three-layer plywood, and when the oxidized cassava starch content was increased to 45%, the dry strength could reach 1.21 MPa, and the wet strength was 0.72 MPa. The FTIR results showed that chemical reaction between UG resin and oxidized cassava starch was beneficial to the branched structure formation and higher cohesion strength of UG resin. Meanwhile, the tightness structure of enhanced UG resin system was observed by SEM analysis as well. These improved properties were contributed to water resistance improvement of UG resin.

    更新日期:2019-12-11
  • Influence of amine functionalized graphene oxide on mechanical and thermal properties of epoxy matrix composites
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-27
    Pavan Paraskar, Pravin Bari, Satyendra Mishra

    A new approach for synthesized amine functionalized graphene oxide (AFGO) was used by diethylenetriamine as a reducing or functionalizing agent. The purpose of this work is to determine the effect of AFGO on the mechanical and thermal properties of epoxy nanocomposites. In addition, the optimization of various weight percentages of AFGO was carried out. Physical and chemical characterizations were also reported to determine the effects of AFGO. The structure and morphology of the AFGO nanosheets were confirmed by fourier transform infrared spectroscopy, energy dispersive spectroscopy, X-ray diffraction analysis, and field emission scanning electron microscopy. Successful formation of amide bonds through graphene oxide (GO) sheet functionalization was proved by characterizations. Solution blending, as a simple method, was used for composite formation. The mechanical and thermal properties of the epoxy/AFGO composites were assessed. There was increment in tensile strength by 67%, flexural strength by 51%, and impact strength by 152% at 0.3 wt% loading of AFGO in epoxy composites. Similarly, the increment in hardness was also observed from 0.1 to 0.3 wt% of AFGO loading. The glass transition temperature of epoxy/AFGO nanocomposites effectively improved from 88.4 to 97.3 °C. The thermal stability of epoxy/AFGO nanocomposite increased from 351 to 358 °C.

    更新日期:2019-12-11
  • Comparative evaluation of Clusia multiflora wood flour, against mineral fillers, as reinforcement in SBR rubber composites
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-14
    Emilio Delgado, Anny Espitia, William Aperador

    Clusia multiflora sawdust (CMS) was evaluated as filler in rubber composites. CMS at 40 phr was mixed with synthetic styrene butadiene rubber (SBR 1502), the blend was compatibilized with 8 phr of maleated polyethylene (MAPE). To evaluate the curing and mechanical behavior of CMS, it was compared with precipitated silica (reinforcing filler); calcium carbonate and kaolin (non-reinforcing minerals). The addition of CMS reduced the mechanical properties of rubber compound compared to silica rubber/silica composite. The tensile and tear strength values for SBR/CMS were similar to SBR/CaCO3 and SBR/kaolin. The addition of MAPE to SBR/CMS composite slightly improved the tensile strength, tear strength, abrasion resistance and hardness. In general, CMS performed as diluent filler which reduced the weight of the composite. CMS slightly affected curing speed of SBR/CMS blends. CMS is a waste generated by the use of Clusia multiflora (a timber species endemic of mountains region of Colombia) in the furniture industry. The novelty of this research consists of evaluating the CMS as an alternative to mineral fillers in rubber compounding to improve its mechanical properties, seeking to contribute to the sustainability and to reduce environmental impacts.

    更新日期:2019-12-11
  • Graphene-filled versus ionic liquid-filled poly(vinylidene fluoride- co -hexafluoropropene) electrolytic membranes for high energy devices: thermophysical and electrochemical aspects
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-14
    Faheem Ullah, Fatima Javed, Hazizan Md. Akil

    The recent developments of membrane technology that requires the composite membrane to work effectively in high energy devices have prompted the inclusion of graphene (GO) and N-butyltrimethylammonium iodide (IL) into a poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-co-HFP) host polymer. From the characterizations that were conducted using FTIR, SEM, TGA, DSC, universal testing machine, Hot Disk Thermal Constants Analyser and the RF impedance spectroscopy, the IL-filled PVDF-co-HFP membrane (1P/IL) was found to have a better dielectric and thermal conductivity, while the decreased porosity of the 1P/GO membrane was discovered to have contributed to its better mechanical performance. Apart from the moieties, which had filled the gaps of the porous architecture and formed a firmer configuration from the chemical junctions with the PVDF-co-HFP, the IL in the membrane was also observed to have increased the density of the accumulated charge carriers and polarization with a better crystallinity control, porosity and ion transportation of the dielectric constant. Based on the above results, the introduction of an ionic liquid (with its plasticizing effect, well-dispersed assembling and diffusional motions) can thus be regarded as significantly improving the properties of the PVDF-co-HFP and particularly in the hi-tech targeted applications of high energy devices such as those of the high-energy Li-ion batteries.

    更新日期:2019-12-11
  • Polytetrafluoroethylene/nanoclay composite as anti-wearing compound
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-11-11
    Sahebali Manafi, Syed Rahim Kiahosseini

    The most important application of polytetrafluoroethylene (PTFE) polymer in industry is its use as a solid lubricant, due to its lack of reactivity with most industrial materials. However, the PTFE polymer has low abrasive resistance that limited its usage. In this research, 0, 2, and 5% of nanoclay were added to PTFE polymer as filler, and properties of the resultant nanocomposites were investigated. For this purpose, the nanoclay was first dissolved in a solution of water and surfactant, and then added into the PTFE. After thoroughly mixing, the cylindrical specimens were produced by cold pressing and heated to 340 °C for 2 h in an atmosphere-protected furnace. EDS analysis, electron scanning microscopy and pin-on-disk wear test were done on nanocomposites. The results of the EDS proved the uniform distribution of nanoclay in the matrix of PTFE. The abrasion test showed that the wear resistance was more than 100 times in the nanocomposite containing 5% nanoclay than PTFE. The investigation of the abrasive particles showed that the particles separated from polymer are longer and thicker than those separated from nanocomposite. By observing the surface of the abrasive pin after the wear test, it became clear that the transfer film from the PTFE polymer was formed on the surface of the abrasive pin and prevented the nanocomposite from the abrasion directly. Therefore, the abrasion mechanism in nanocomposites is “abrasive” due to the surface adhesion.

    更新日期:2019-12-11
  • Multi-stimuli-responsive poly(hydroxyethyl methacrylate- co - N -vinyl pyrrolidone- co -methacrylic acid- co - N -isopropylacryl amide) hydrogel: synthesis, characterization and application in drug release
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-10-22
    Xiaoli Yang, Kunyan Wang, Lei Yan, QiNing Yu, Hongxia Xia, Yanbo Liu, Chengjun Yan

    Multi-stimuli-responsive hydrogels are being increasingly studied due to their sensitive response to small stimuli and wide applications in biosensors and drug delivery. In this study, a multi-stimuli-responsive hydrogel, poly(hydroxyethyl methacrylate-co-N-vinyl pyrrolidone-co-methacrylic acid-co-N-isopropylacryl amide) [poly(HEMA-co-NVP-co-MAA-co-NIPA)], was synthesized by radical polymerization and characterized by Fourier transform infrared (FTIR) and 13C NMR spectroscopy techniques. With the aids of scanning electron microscopy (SEM) characterization, it was confirmed that the sensitive stimuli-responsive behavior of the hydrogel stemmed from its microstructure variation with those external stimulus. Rheological study showed that the hydrogel had rheological feature of typical elastomer. Compression tests revealed that the poly(hydroxyethyl methacrylate-co-N-vinyl pyrrolidone) [poly(HEMA-co-NVP)] played an important role in enhancing the compressive modulus of such hydrogel. More interestingly, the equilibrium swelling ratio (ESR) studies further confirmed that the composite hydrogel displayed response sensitively to the stimulus of temperature, pH, and ionic strength. Herein, theophylline as a drug model was adopted due to the multi-stimulus properties of hydrogels, which were a potential candidate for drug loading and delivering. Releasing drug continuously in a given period was dependent on the characteristics of solution and loading time. The mechanisms for drug release from the hydrogels were studied by Ritger–Peppas model.

    更新日期:2019-12-11
  • Synthesis of an alkynyl neutral polymer-bonding agent and its enhancing effect on tensile strength of glycidyl azide polymer-based propellants
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-10-16
    Shuiping Zhou, Gen Tang, Aimin Pang, Xiang Guo, Fang Wu, Huibin Song, Xingxing Xu, Xiang Hu, Yanpin Wang

    A novel alkynyl neutral polymer-bonding agent (NPBA) was synthesized by a three-step approach. The molecular structure and thermal characteristics of alkynyl NPBA were analyzed. To reveal the influence of alkynyl NPBA on the mechanical properties of glycidyl azide polymer (GAP)-based propellants, two types of GAP propellants with Desmodur N-100 and alkynyl-terminated polyethylene glycol (APE) as curing agents were prepared and mechanical properties of the propellants were fully investigated. Tensile strength and initial modulus of propellants were notably promoted with the increase in alkynyl groups content of alkynyl NPBA with Desmodur N-100 as curing agent. The interfacial adhesion property between GAP binders and CL-20 fillers was greatly improved by alkynyl NPBA, and dewetting phenomenon of propellants during uniaxial tension was markedly attenuated. The wettability of GAP binders and solid fillers was good and the enhancing effect of alkynyl NPBA on tensile strength of GAP propellants was notable. Tensile strength and initial modulus of propellants were notably increased and their maximum elongation was decreased with the increase of alkynyl group content of alkynyl NPBA in propellants when APE was used as a curing agent. In addition, the dynamic mechanical analysis results showed that internal friction resistance of GAP molecular segment motion of GAP propellants was increased and interactions between GAP binder and solid fillers became much stronger with alkynyl NPBA. A notable enhancement effect on tensile strength and initial modulus of GAP propellants was demonstrated with alkynyl NPBA as bonding agent.

    更新日期:2019-12-11
  • Balanced strength and toughness improvement in polylactide (PLA)/poly(1,4-cyclohexylene dimethylene terephthalate glycol) (PCTG) blends using various compatibilizers
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-10-25
    Hong-Jiang Song, Xiao-Dong Chen, Jin-Chen Fan, Qun-Jie Xu

    Generally, improving the toughness of polylactic acid (PLA) is very important for its practical applications. Blending with elastomer is considered to be the effective way for property modification of PLA. As an efficient toughener, the elastomer poly(1,4-cyclohexylene dimethylene terephthalate glycol) (PCTG) showed great potential in improving the toughness of PLA. However, the compatibility between PLA and PCTG is still a key problem. Here, the PLA/PCTG blends with various compatibilizers of SOG-02, SAG-008, and AX8900 were successfully prepared using melt compounding. The compatibility effects of SOG-02, SAG-008, and AX8900 on PLA/PCTG blends were investigated from their mechanical properties, thermal stabilities, melt flow rates, and crystallization behavior. Based on the results, SOG-02 showed the best compatibilizing effect on PLA/PCTG blends among the used compatibilizers. More importantly, it is worth noting that use of SOG-02 together with AX8900 further enhanced its compatibilizing effect on the PLA/PCTG blends with obvious improvements in mechanical properties and toughness. After blending with 3 wt% of SOG-02 and 2 wt% of AX8900, the tensile and bend strengths of PLA/PCTG/SOG-02/AX8900 were ~ 52.9 and ~ 67.2 MPa, respectively. In the meantime, the PLA/PCTG/SOG-02/AX8900 still kept benign notched impact strength (~ 6.3 MPa) and high elongation-at-break (~ 12.7%).

    更新日期:2019-12-11
  • In situ Bi 2 O 3 -loaded polypyrrole nanocomposites for carbon dioxide gas sensing
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-10-03
    Ashish R. Choudhary, Sandeep A. Waghuley

    In the present work, an attempt has been made to detect carbon dioxide (CO2) using an in situ-loaded Bi2O3–polypyrrole nanocomposite sensor. The polypyrrole (PPy) was prepared by oxidative polymerization method from precursor’s monomer pyrrole and aqueous solution of ammonium persulphate. The prepared nanocomposites were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV–Vis), thermogravimetric–differential thermal analysis (TG–DTA) and Raman spectroscopy. Thick films of the synthesized PPy nanocomposites were deposited on glass substrate by screen printing technique. Resistive type gas sensors are extensively used in a number of modern applications such as emission control and energy efficiency. By considering this view, PPy nanocomposite films were prepared for gas sensing application. The XRD analysis revealed amorphous nature. The SEM micrograph showed that nanocomposite particles have irregular morphology and size. The nanocomposites showed a good sensing performance toward CO2 gas. The highest value of CO2 gas sensing response was shown by 25 wt% Bi2O3-loaded PPy nanocomposite sample (S5), which was found to be 0.065 for 50 ppm. Operating temperature for the optimized sample S5 toward CO2 gas was found to be 363 K. Similarly, the optimized sample S5 showed an excellent stability response against CO2 gas and atmospheric change for 30 days.

    更新日期:2019-12-11
  • Synthesis and characterization of hexagonal boron nitride coating on polyethylene terephthalate
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-10-21
    Muthuvel Sattanathan, Shanmugan Subramani, Khairudin Mohamed, Mutharasu Devarajan, Ramdziah Md Nasir

    Hexagonal Boron Nitride (h-BN) thin film was deposited on flexible polyethylene terephthalate (PET) substrate using radio frequency (RF) magnetron sputtering system. Ceramic material h-BN was coated at three different thicknesses of 400 nm, 800 nm and 1200 nm on PET surface for a detailed comparative study. A clearer topography of the h-BN-coated surface on PET substrate was imaged using field emission scanning electron microscopy (FESEM) system, where it depicted well-developed grain boundaries. The existence of B–N components was ensured by peaks observed at 1442 and 817 cm−1 using Fourier-transform infrared spectroscopy (FTIR) study. X-ray diffractograms (XRD) confirmed the presence of (100) and (004) oriented BN phases in the prepared thin films. Increase in surface roughness (10.2–55.2 nm) from surface analysis and moderate improvement in thermal conductivity also obtained in this work was evident. Characterization studies support the novelty in the study of the deposition of h-BN thin film on flexible PET substrate with improved surface roughness and thermal conductivity. The conclusion was that BN thin film can be suggested as a potential object as heat spreader in flexible electronics for efficient thermal management devices such as electronic packaging applications.

    更新日期:2019-12-11
  • Development of gelatin/chitosan membranes with controlled microstructure by electrospinning
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-10-01
    Víctor Perez-Puyana, Manuel Felix, Leticia Cabrera, Alberto Romero, Antonio Guerrero

    Electrospun membranes obtained through electrospinning are very promising since they exhibit a high porosity and surface area. The present study proposes the use of gelatin (GL) made from fish by-products in combination with a polycationic polysaccharide (chitosan, CH) and a water-soluble polymer (polyethylene oxide, PEO) to obtain unitary, binary or even ternary nanofibrous membranes which would be suitable in different applications, such as biomaterials or filtration industry. This work aims to correlate the microstructure of final ternary membranes (GL–CH–PEO) and the properties of the solutions by evaluating their viscosity obtained through rheological characterization, as well as their conductivity and density, which are key parameters to obtain a suitable electrospinning processing technique. The results indicate that membranes with a fairly homogeneous distribution of fibers can be obtained using either biopolymer/PEO binary solutions (i.e., 00/85/30 or 05/00/35 systems) or even ternary solutions (05/85/35 or 05/85/35) with diameters shorter than 200 nm. In this sense, physicochemical characterization of the polymer/biopolymer solutions used for electrospinning processing technique is essential for the understanding of this technique.

    更新日期:2019-12-11
  • Effect of ionomer/multiplet formation on mechanical properties and ascorbic acid release behavior of PNIPAAm hydrogels copolymerized by DMAEMA, DMAPMAAm and MAPTAC
    Iran. Polym. J. (IF 1.707) Pub Date : 2019-10-29
    Ceyda Şimşek, Zeynep Ezgi Eroğlu, Candan Erbil

    Poly(N-isopropylacrylamide) (PNIPAAm) hydrogels containing N-[3-(N,N-dimethylamino)propyl]methacrylamide (DMAPMAAm), 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) and [3-(methacryloylamino)propyl]trimethylammonium chloride (MAPTAC) as cationic monomers were cross-linked with N,N’-methylenebisacrylamide (BIS) and tetraallylammonium bromide (TAB). The swelling degrees, uniaxial compression moduli and L-ascorbic acid (L-AA) releases of these cationic PNIPAAm hydrogels synthesized in 1,4-dioxane were compared with the one prepared in distilled–deionized water (DDW) and in aqueous sodium hydroxide solution (0.1 N NaOH). P(NIPAAm-co-MAPTAC)/BIS and P(NIPAAm-co-DMAEMA)/BIS hydrogels at 37 °C in DDW and at 37 °C/pH 4 exhibited higher gel strengths and compressive moduli than all the others cross-linked and copolymerized with TAB and DMAPMAAm, respectively. All the observations indicated that the physical cross-linking points created by ionomer pairs of MAPTA+Cl− units and the hydrophobic contributions of ester groups in the DMAEMA units might be a reason of their improved mechanical properties in DDW at 37 °C. Further, the charge screening effect of chloride ions in the swelling medium at pH 4 also resulted in the improved compressive moduli compared to the ones in DDW. The water diffusion into/from all the copolymeric PNIPAAm hydrogels during the swelling/deswelling processes at 25 °C/37 °C in DDW and their L-AA releases at 37 °C in DDW also revealed the importance of these ionic and hydrophobic effects. Water transport through the ones cross-linked with TAB was controlled by non-Fickian process due to the repulsive forces between the quaternized ammonium groups on the chemical cross-links while in the case of P(NIPAAm-co-MAPTAC)/BIS, water transport followed Fickian diffusion because the multiplet formations behaved as additional cross-links. Furthermore, P(NIPAAm-co-MAPTAC)/BIS hydrogel due to the ionomer-multiplet transitions at 37 °C in DDW has exhibited less-Fick diffusion that resulted in a lower diffusion coefficient during the release of L-AA as compared to the others.

    更新日期:2019-12-11
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