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  • Quantitative evaluation on oil diffusion mechanisms in nano‐organic‐montmorillonite modified caster oil‐based polyurethane foam for oil/water separation
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-24
    Xinxing Zhou; Qiong Huang

    To improve the oil absorbency of caster oil‐based polyurethane foam, nano‐organic‐montmorillonite (OMMT) was used for the additives. The aim of this study is to evaluate the oil diffusion mechanism and dispersion uniformity of OMMT modified caster oil‐based polyurethane (MPU) using experiments and molecular dynamic simulation. Molecule movement and molecule trajectory of oil was investigated by molecular dynamic simulation and numerical simulation. According to the quantitative analyzing results, the diffusion model was put forward. The average diffusion coefficient of crude oil in 0, 1, 2 wt%, 4, and 6 wt% MPU is 2.4 × 10−4 cm2/s, 2.6 × 10−4 cm2/s, 3.0 × 10−4 cm2/s, 3.2 × 10−4 cm2/s, and 3.3 × 10−4 cm2/s, respectively. It indicated that crude oil appeared gradient in the MPU. The optimal diffusion direction of crude oil is (0, 0, 1) crystal face, and the small particles of crude oil are easy to be adsorbed. The two‐dimensional diffusion trajectory of crude oil is nonlinear. The diffusion model includes the diffusion of crude oil at the interface of oil and polyurethane, surface diffusion and pore diffusion, and pore adsorption. Furthermore, the diffusion model showed that the van der Waals force was the main reason for crude oil diffusion or adsorption. OMMT could improve the ability of oil/water separation of polyurethane.

    更新日期:2020-01-24
  • Prediction of branch on branch and topological characteristics of low‐density polyethylene polymerization by a novel stochastic approach
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-24
    Ahmad Reza Taheri; Mohammad Najafi; Siamak Motahari

    A novel approach using Monte Carlo method applied to simulation of low‐density polyethylene (LDPE) polymerization in tubular reactor showing topological characteristics, and the comprehensive kinetic mechanism has been taken into consideration. The results show the precise details of the structure of a chain in the three levels of the backbone, the main branches, and branches on branch. The chain types include dead polymer, dead polymer with unsaturated end, and live polymer with primary radical, secondary radical, and tertiary radical. In this work, the branches on branch were identified in terms of number, length, and position of the branch. Sixty percent of branches on branch are 1 to 5 carbons long, and the longest branch on branch is about 50 carbons. Thus, this study provides a tool for more accurately mapping the polymer chains architecture, superior to determine the number, and position of long‐ and short‐chain branches in past researches. Finally, this approach will advance the prediction of microstructure‐related properties of polymer one step further.

    更新日期:2020-01-24
  • Fabrication of ZIF‐8@Polyphosphazene core‐shell structure and its efficient synergism with ammonium polyphosphate in flame‐retarding epoxy resin
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-23
    Xinyao Lv; Wei Zeng; Zhiwang Yang; Yaoxia Yang; Yun Wang; Ziqiang Lei; Jinling Liu; Denglong Chen

    A novel zeolitic imidazolate framework (ZIF‐8) nanoparticles@polyphosphazene (PZN) core‐shell architecture was synthesized, and then, ZIF‐8@PZN and ammonium polyphosphate (APP) were applied for increasing the flame retardancy and mechanical property of epoxy resin (EP) through a cooperative effect. Herein, ZIF‐8 was used as the core; the shell of PZN was coated to ZIF‐8 nanoparticles via a polycondensation method. The well‐designed ZIF‐8@PZN displayed superior fire retardancy and smoke suppression effect. The synthesized ZIF‐8@PZN observably raised the flame retardancy of EP composites, which could be demonstrated by thermogravimetric analysis (TGA) and a cone calorimeter test (CCT). The chemical structure of ZIF‐8@PZN was characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Compared with pure epoxy, with the incorporation of 3 wt% ZIF‐8@PZN and 18 wt% APP into the EP, along with 80.8%, 72.6%, and 64.7% decreased in the peak heat release rate (pHRR), the peak smoke production rate (pSPR), and the peak CO production rate (pCOPR), respectively. These suggested that ZIF‐8@PZN and APP generated an intumescent char layer, and ZIF‐8@PZN can strengthen the char layer, resulting in the enhancement in the flame resistance of EP.

    更新日期:2020-01-24
  • Phosphorus‐containing Salen‐metal complexes investigated for enhancing the fire safety of thermoplastic polyurethane (TPU)
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-23
    Yabin Zhang; Jinfeng Cui; Lurong Wang; He Liu; Baoping Yang; Junhong Guo; Bo Mu; Li Tian

    Three novel phosphorus‐containing Salen‐based derivatives (Salen‐DPCP‐M: M = Ni, Zn, and Mn), which include both phenyl phosphate structures (DPCP) and Salen‐metal complexes, were prepared for enhancing the fire safety of thermoplastic polyurethane (TPU). Thermogravimetric analysis (TGA) showed that Salen‐DPCP‐M altered the thermal degradation pathways of TPU probably due to the phosphorus‐containing structure of Salen‐DPCP‐M. The cone calorimeter test showed that the addition of 3 wt% of Salen‐DPCP‐Ni, Salen‐DPCP‐Zn, and Salen‐DPCP‐Mn lowered the peak of heat release rate (PHRR) from 1495 kW/m2 for neat TPU to 690, 875, and 813 kW/m2, respectively, for the TPU composites, which demonstrated that Salen‐DPCP‐M improved the fire safety of TPU. In addition, the release of toxic CO gas from the Salen‐DPCP‐Ni/TPU and Salen‐DPCP‐Zn/TPU composites was reduced by 78.2% and 80.0%, respectively. The results of TGA/infrared spectrometry (TG‐FTIR) showed that the incorporation of Salen‐DPCP‐Ni promoted the release CO2, while reducing the formation of harmful gases. Laser Raman spectroscopy (LRS) and scanning electron microscopy (SEM) showed that Salen‐DPCP‐Ni/TPU and Salen‐DPCP‐Zn/TPU composites formed a dense and stable char layer. Herein, the mechanism of these flame retardants containing novel phosphorus‐containing Salen‐metal complexes is also proposed.

    更新日期:2020-01-24
  • Construction of superhydrophilic/underwater superoleophobic polydopamine‐modified h‐BN/poly(arylene ether nitrile) composite membrane for stable oil‐water emulsions separation
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-20
    Guiyuan Zhang; Yingqing Zhan; Shuangjiang He; Lianhong Zhang; Guangyong Zeng; Yu‐Hsuan Chiao

    Oil/water emulsion separation in harsh environments remains a big challenge. Herein, a double layered nanofibrous composite membrane was developed by assembly of polydopamine‐modified hexagonal boron nitride (h‐BN‐PDA) onto a poly(arylene ether nitrile) (PEN) nanofibrous mat. Owing to the synergistic effect of a h‐BN‐PDA skin layer and a PEN nanofibrous mat supporting layer, as‐prepared composite membrane exhibited high thermal stability, corrosion resistance, and superhydrophilic/underwater superoleophobic property. Consequently, the PEN composite membrane showed good antifouling performance and a high rejection ratio (>99.0%) for various oil/water emulsions. After 10 cycles, the separation flux of PEN composite membrane still reached 588.1 L/m2 h under the operating pressure of 0.04 MPa. Furthermore, the PEN composite membrane could still achieve high separation efficiency and high flux in high‐temperature (65 °C) and strongly corrosive conditions (pH = 1‐13). Therefore, the stable and efficient h‐BN‐PDA/PEN composite membrane showed potential application for treating oily wastewater in harsh environments.

    更新日期:2020-01-22
  • Poly(ester imide)s possessing low coefficients of thermal expansion and low water absorption (IV): Effects of ester‐linked tetracarboxylic dianhydrides with longitudinally extended structures
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-20
    Masatoshi Hasegawa; Takayuki Saito; Yumi Tsujimura

    A series of poly(ester imide)s (PEsIs) were prepared using longitudinally extended structures of ester‐linked tetracarboxylic dianhydrides with different numbers of aromatic rings (NAr = 4‐6). In the PEsIs obtained using p‐phenylenediamine (p‐PDA), a clear trend was observed: the water absorption (WA) decreased with increasing NAr. In contrast, no clear decrease in the Tg with increasing NAr was observed for the PEsIs obtained using 4,4′‐oxydianiline (4,4′‐ODA). The PEsIs obtained using a methyl‐substituted tetracarboxylic dianhydride (NAr = 5) showed more suppressed WA and higher elongation at break (εb) values than those of the nonsubstituted counterparts. The former result is probably closely related to the enhanced crystallinity. However, methyl substitution caused an appreciable reduction in the thermal stability. Thus, the methyl‐substituted PEsIs did not meet the V‐0 standard in the UL‐94V test, unlike the substituent‐free counterparts. The PEsI copolymer obtained using the substituent‐free tetracarboxylic dianhydride (NAr = 6) with p‐PDA (75 mol%) and 4,4′‐ODA (25 mol%) had excellent combined properties, ie, a very high Tg (361°C), an ultralow coefficient of thermal expansion (2.2 ppm K−1), an extremely low coefficient of hygroscopic expansion (3.3 ppm/RH%), moderate film ductility (εbmax = 23%), a moderate dielectric constant (3.22), and a low tan δ (2.76 × 10−3) at 10 GHz in 50% relative humidity. Thus, this PEsI is a promising novel dielectric substrate material for use in the next generation of high‐performance flexible printed circuit boards.

    更新日期:2020-01-21
  • Rapid electrothermal response and excellent flame retardancy of ethylene‐vinyl acetate electrothermal film
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-17
    Wenxiang Tian; Yan Zhang; Jiajia Liu; Wenhua Cheng; Jingyi Lu; Lei Song; Bibo Wang; Yuan Hu

    In this study, high electrical conductivity and flame retardant electrothermal ethylene‐vinyl acetate (EVA) films were fabricated by using carbon nanotubes‐wrapped ammonium polyphosphate (CAPP) and conductive carbon black (CCB). CAPP was used as a synergistic conductive filler and flame retardant to improve the electrical conductivity and fire safety of the electrothermal film at the same time. Besides, the heat release rate (HRR) and the total heat release (THR) of EVA‐5 decreased about 81.5% and 57.3% compared with those of pure EVA film, respectively. Moreover, by incorporating a small amount of CAPP, EVA‐5 can reach up to V‐0 rating with an limiting oxygen index (LOI) value of 31%. EVA film fabricated by CCB and CAPP as conductive material exhibited almost 10 times increment on electrical conductivity than that of same content for CCB alone. And time vs temperature profiles of EVA‐5 showed a stable trend over 3600 seconds without any offset at a given applied voltage of 15 V. Moreover, its excellent cycle heating performance indicated that the electrothermal film can be recycled, which meets the requirements of sustainable development. In a word, this novel strategy provides a simple and effective way to obtain a high conductive and fire safety electrothermal film.

    更新日期:2020-01-17
  • Issue Information
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-14

    No abstract is available for this article.

    更新日期:2020-01-15
  • Engineering biodegradable polymeric network for the efficient removal of organo‐amphiphilic toxicants
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-09
    Rajan Kumar; Anubhav Rajpoot; Amritangshu Roy; Raja Shunmugam

    Motivated with the continued demand for developing quality material showing better response for the efficient removal of organo‐amphiphilic toxicants, we have demonstrated the growth of three‐dimensional polymer organic framework—a covalent crosslinked polymer C2B derived via photon triggered thiol‐alkene click reaction. Instrumentation techniques such as nuclear magnetic resonance, thermogravimetric analysis, and fourier transform infrared spectroscopy were used for the characterization. FESEM and Cryo‐SEM analysis were done to analyze the morphology of the resin. The adsorption and release experiments were done with ultraviolet‐visible spectroscopic technique. The polymer C2B derived from polyolefin and tetrathiol via thiol‐alkene photoclick reaction showed efficiency toward adsorption of organo‐amphiphilic contaminants such as dioxane, dimethylformamide, fluorescein, and rhodamine B (RH). Even the material selectively showed the efficient release of toxicant—RH. Moreover, it can be reused over cycles. This makes the polymer C2B as potential candidate to be commercially viable for textile industries.

    更新日期:2020-01-11
  • Mussel‐inspired method to decorate commercial nanofiltration membrane for heavy metal ions removal
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-07
    Xiang Liu; Pengyu Feng; Lei Zhang; Yonggang Chen

    Nanofiltration (NF) membranes have been widely used for the treatment of electroplating, aerospace, textile, pharmaceutical, and other chemical industries. In this work, halloysite nanotubes (HNTs) were directly anchored on the surface of commercial nanofiltration (NF) membrane by dopamine modification following advantageous bio‐inspired methods. SEM and AFM images were used to characterize the HNTs decorated membrane surface in terms of surface morphology and roughness. Water contact angle (WCA) was employed in evidencing the incorporation of HNTs and dopamine in terms of hydrophilicity or hydrophobicity. Augmentation of HNTs was found to obviously enhance the hydrophilicity and surface roughness resulting in improved water permeability of membrane. More importantly, the rejection ratios of membrane also increased during the removal of heavy metal ions from wastewater. The permeability and Cu2+ rejection ratio of modified NF membrane were as high as 13.9 L·m−2·h−1·bar−1 and 74.3%, respectively. Incorporation of HNTs was also found to enhance the anti‐fouling property and stability of membrane as evident from long‐term performance tests. The relative concentration of HNTs and dopamine on membrane surface was optimized by investigating the trade‐off between water permeability and rejection ratio.

    更新日期:2020-01-07
  • Supramolecular self‐assembly modification of ammonium polyphosphate and its flame retardant application in polypropylene
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2020-01-06
    Congrui Qi; Bihe Yuan; Haoran Dong; Kaiyuan Li; Sheng Shang; Yaru Sun; Gongqing Chen; Yuanyuan Zhan

    In order to improve its water resistance and compatibility with polymer matrix, ammonium polyphosphate (APP) is modified with melamine‐trimesic acid (MEL‐TA) aggregates by supramolecular self‐assembly technology. Chemical structure and morphology of APP@MEL‐TA are investigated by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM), respectively. Intumescent flame retardant system of APP@MEL‐TA and charring‐foaming agent is introduced into polypropylene (PP) matrix. The flammability and combustion behavior of PP composites are investigated by limiting oxygen index (LOI), UL‐94 vertical burning, and cone calorimetry tests. In terms of LOI values and cone combustion results, APP@MEL‐TA performs better than pristine APP. Char residue of PP composites is investigated by SEM and Raman spectra. Flame retardant mechanisms are proposed based on thermal decomposition, combustion results, and analysis on char residue.

    更新日期:2020-01-07
  • Antibody drug conjugates: Development, characterization, and regulatory considerations
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-30
    Nagavendra Kommineni; Palpandi Pandi; Naveen Chella; Abraham J. Domb; Wahid Khan

    Previously, cancer chemotherapy was often accompanied by severe side effects. Antibody drug conjugates (ADCs) were introduced to address this treatment complication. ADCs are a potent category of bioconjugates and immunoconjugates designed as targeted therapy for the treatment of cancer. ADCs are complex molecules composed of an antibody linked via linker chemistry to a cytotoxic payload or drug. Therefore, biologic properties of the cell‐surface target antigen are important in designing an effective ADC as an anticancer agent. ADCs have the ability to discriminate between the healthy and diseased tissue, so that healthy cells are less effected and get maximum therapeutic benefit. This review describes the development, characterization, and regulatory consideration of ADCs, and it summarizes the approved products in the market and in clinical trials.

    更新日期:2019-12-30
  • Synthesis and properties of shape memory polymers of LLA, TMC, and ε‐CL terpolymers
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-30
    Shaohua Wen; Yongfei Li

    Biodegradable polylactide (PLA) and its copolymers with shape memory properties have attracted great interests because of their important application prospects in biomedical field. In this study, random poly(L‐lactide‐co‐trimethylene carbonate‐co‐ε‐caprolactone) (LTCL) terpolymers with different molar ratio were synthesized and characterized. Monomer ε‐caprolactone (ε‐CL) was used in this study instead of glycolide in preliminary study of LTG terpolymers to investigate the transition temperature and the shape memory performance. Characterization on crystallization, mechanical properties, shape fixing, and recovery ratios of the terpolymers was conducted to investigate the correlation between crystallization and shape memory performance of LTCL terpolymers. The results are consistent with the formation of crystallized LLA segments, which could act as crosslinks, strengthened the stationary phase within the polymer matrix, and significantly improved the shape memory performance of LTCL terpolymers. For example, LTCL801010 is a crystalline polymer with high shape fixity and shape recovery ratio; its shape recovery temperature is 39°C. LTCL terpolymers with high CL content do not show shape memory performance for the rubbery at room temperature. Based on this study, PLA materials with shape memory property can be designed through the selection of monomers or the adjustment of comonomer ratio. These polymers with recovery temperature close to 37°C are expected to be used in human body such as scaffolds in tissue engineering.

    更新日期:2019-12-30
  • The electrospun poly(ε‐caprolactone)/fluoridated hydroxyapatite nanocomposite for bone tissue engineering
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-30
    Narges Johari; Mohammadhossein Fathi; Zeinab Fereshteh; Saeid Kargozar; Ali Samadikuchaksaraei

    Biodegradable cell‐incorporated scaffolds can guide the regeneration process of bone defects such as physiological resorption, tooth loss, and trauma which medically, socially, and economically hurt patients. Here, 0, 5, 10, and 15 wt% fluoridated hydroxyapatite (FHA) nanoparticles containing 25 wt% F− and 75 wt% OH− were incorporated into poly(ε‐caprolactone) (PCL) matrix to produce PCL/FHA nanocomposite scaffolds using electrospinning method. Then, scanning electron microscopy (SEM), X‐ray diffraction (XRD) pattern, and Fourier transform infrared spectroscopy (FTIR) were used to evaluate the morphology, phase structure, and functional groups of prepared electrospun scaffolds, respectively. Furthermore, the tensile strength and elastic modulus of electrospun scaffolds were investigated using the tensile test. Moreover, the biodegradation behavior of electrospun PCL/FHA scaffolds was studied by the evaluation of weight loss of mats and the alternation of pH in phosphate buffer saline (PBS) up to 30 days of incubation. Then, the biocompatibility of prepared mats was investigated by culturing MG‐63 osteoblast cell line and performing MTT assay. In addition, the adhesion of osteoblast cells on prepared electrospun scaffolds was studied using their SEM images. Results revealed that the fiber diameter of prepared electrospun PCL/FHA scaffolds alters between 700 and 900 nm. The mechanical assay illustrated the mat with 10 wt% FHA nanoparticles revealed the highest tensile strength and elastic modulus. The weight loss alternation of mats determined around 1% to 8% after 30 days of incubation. The biocompatibility and cell adhesion of mats improved by increasing the amounts of FHA nanoparticles.

    更新日期:2019-12-30
  • Efficient approach to enhancing the fire resistance of polypropylene by modified microporous aluminosilicate from kaolinite as synergist
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-28
    Xiaoyu Gu; Yufei Wang; Xiaodong Liu; Sheng Zhang; Hongfei Li; Jun Sun; Xiaodong Jin; Wufei Tang

    In this work, kaolinite (K) was firstly converted to one kind of microporus aluminosilicate (4A) by a green andeconomical method, which was thenacted as the precursor to synthesize two other microporus aluminosilicate (3A and 5A) by ions exchange. After modified and loaded with one kind of rare earth ion (La3+), the final product (A‐La) was then used as synergist to enhance fire retardant property for polypropylene (PP) with intumescent flame‐retardants (IFR). The properties of PP composites for thermal stability and flame retardant were studied and demonstrated that A‐La, especially 4A‐La, had the most obviously flame‐retardant effect. Meanwhile, the macro/micro‐structure of char residues and real‐time fourier transform infrared spectroscopy (FTIR) after heating also showed that A‐La were helpful to promote the formation of homogenous and compact intumescent char layer. This dense carbon layer can effectively control the convection of combustion gases mixture, and heat transfer between underlying matrix and outside environment.

    更新日期:2019-12-29
  • Preparation of piperazine cyanurate by hydrogen‐bonding self‐assembly reaction and its application in intumescent flame‐retardant polypropylene composites
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-28
    Haoran Dong; Bihe Yuan; Congrui Qi; Kaiyuan Li; Sheng Shang; Yaru Sun; Gongqing Chen; Hongming Zhang; Xianfeng Chen

    Piperazine cyanurate (PCA) is designed and synthesized via hydrogen‐bonding self‐assembly reactions between piperazine and cyanuric acid. Chemical structure and morphology of PCA are investigated by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The prepared PCA is combined with ammonium polyphosphate (APP) to prepare flame‐retardant polypropylene (PP) composites. Thermostability, flammability, and combustion characteristics of PP composites are analyzed. The maximum thermal decomposition rate of flame‐retarded PP composites has an apparent reduction compared with that of pure PP, and obvious char is left for this intumescent flame retardant (IFR) system of APP and PCA. A high limiting oxygen index value and UL‐94 V‐0 rating are achieved with addition of APP and PCA. In cone calorimetry test, heat and smoke releases of PP are significantly decreased by this IFR system. Gaseous decomposition products during the thermal decomposition of flame‐retardant composites are studied. Chemical structure and morphology of char residues are analyzed. The results illustrate that APP and PCA have a superb synergistic action in the aspect of improvement in fire safety of PP. A possible flame‐retardant mechanism is concluded to reveal the synergism between APP and PCA.

    更新日期:2019-12-29
  • Preparation of hydrophobic tannins‐inspired polymer materials via low‐ppm ATRP methods
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-28
    Izabela Zaborniak; Paweł Chmielarz; Monika Flejszar; Karolina Surmacz; Robert Ostatek

    The novel hydrophobic coating material was received for the first time by a two‐step synthetic route. Firstly, the 15‐functional brominated macroinitiator was prepared by the esterification methodology. Next step covers synthesis of star‐like polymers by poly(n‐butyl acrylate) (PBA) arms polymerization via three low‐ppm atom transfer radical polymerization (ATRP) approaches including application of copper and silver wire in SARA and ARGET ATRP, respectively, as driving forces in redox cycle of catalyst, and an external stimulus in the form of electric current (seATRP) as the third approach in copper(II) regeneration system. As expected, the electrochemically mediated technique allows synthesis of tannic acid‐inspired coating polymers in precisely controlled manner during the entire polymerization process, proved by linear first‐order kinetics plot in contrast to above‐mentioned methods, low dispersity (Ð = 1.18) of star‐shaped polymers, and high efficiency of initiation (ƒ i = 81%) determined after detaching of polymers side arms. Macromolecules received by all low‐ppm ATRP solutions were characterized by preserved chain‐end functionality (theoretical dead chain fraction; DCFtheo <1%). Adhesive and hydrophobic properties of received polymer materials were investigated by contact angles (θ) and free surface energy (FSE) calculations. Prepared polymer films besides excellent hydrophobic properties have great potential as a self‐healing solution.

    更新日期:2019-12-29
  • Preparation of novel, liquid, solvent‐free, polyolefin‐based adhesives
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-28
    Ahad Hanifpour; Naeimeh Bahri‐Laleh; Mehdi Nekoomanesh‐Haghighi
    更新日期:2019-12-29
  • Nanocomposite structures of polypyrrole derivatives and poly (acrylonitrile‐co‐itaconic acid) produced by in situ polymerization as carbon nanofiber precursor
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-26
    Havva Baskan; Ezgi Ismar; Hale Karakas; A. Sezai Sarac

    This study aimed to produce nanoparticles of poly (acrylonitrile‐co‐itaconic acid) (P (AN‐co‐IA)) containing conjugated polymers of pyrrole, N‐Methylpyrrole, 2,5‐dimethylpyrrole, and 1‐(Triisopropylsilyl)pyrrole which were synthesized by emulsion polymerization. Nanocomposite structures of P (AN‐co‐IA)/polypyrrole and polymer of pyrrole derivatives were produced via in situ polymerization, and the nanoparticle formation were followed by morphologic and ultraviolet‐visible (UV‐Vis) spectroscopic methods. Characterizations were made by Fourier transform infrared‐attenuated total reflectance (FTIR‐ATR) and Raman spectroscopy. Atomic force microscopy (AFM) was used for investigating the surface characteristics of the nanoparticles. Characterization results revealed that nanoparticles containing conjugated polymers had rougher surface than P (AN‐co‐IA) nanoparticles. It was also observed that the nanoparticles were well‐distributed although having some agglomerates. Moreover, depending on the type of monomer of conjugated polymer, the shape and size of the produced nanoparticles differed by conjunction with their polymerization rate. These findings can be used as a startup information for production of carbon nanofibers (CNFs) with desired properties after oxidation and carbonization, and as a high‐performance and cost‐effective flame and heat‐resistant material (oxidized copolymers of polyacrylonitrile nanofiber).

    更新日期:2019-12-27
  • The effect of 3D printing on the morphological and mechanical properties of polycaprolactone filament and scaffold
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-26
    Anahita Ahmadi Soufivand; Nabiollah Abolfathi; Ata Hashemi; Sang Jin Lee

    Three‐dimensional (3D) printing becomes an attractive technique to fabricate tissue engineering scaffolds through its high control on fabrication and repeatability using the printing parameters. This technique can be combined by the finite element method (FEM), and tissue‐specific scaffolds with desirable morphological and mechanical properties can be designed and manufactured. In this study, the influential 3D printing parameters on the morphological and mechanical properties of polycaprolactone (PCL) filament and scaffold were studied experimentally and numerically. First, the effects of printing parameters and process on the properties of extruded PCL filament were investigated. Then, using FEM, the effects of filament specifications on the overall characteristics of the scaffold were evaluated. Results showed that both the printing process in terms of resting time and remaining time and the printing parameters like pressure, printing speed, and printing path length have influenced the filament properties. In addition, both the filament diameter and elastic modulus had significant effects on the properties of scaffold especially, a 20% increase in the filament diameter caused the scaffold compressive elastic modulus to rise by around 72%. It is concluded that the printing parameters and process must be tuned very well in fabricating scaffolds with the desired morphology and mechanical property.

    更新日期:2019-12-27
  • Effects of divinylbenzene‐maleic anhydride copolymer hollow microspheres on crystallization behaviors, mechanical properties and heat resistance of poly(l‐lactide acid)
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-22
    Hu Qiao; Jia Guo; Li Wang; Jun Sun; Shengling Jiang; Sheng Zhang; Wantai Yang; Xiaoyu Gu; Hongfei Li

    Divinylbenzene‐maleic anhydride copolymer hollow microspheres (DMs) were used as novel organic nucleating agents to promote crystallization of poly(l‐lactide acid) (PLLA). The effects of these DMs on crystal behaviors of the PLLA were investigated by differential scanning calorimeter (DSC), polarizing optical microscopy (POM), and wide angle X‐ray diffraction (WAXD). Both isothermal and non‐isothermal processes in DSC demonstrated that the DMs significantly altered the crystal behaviors of PLLA as both crystallization velocity and degree of crystallinity increased with increasing DM loadings from 0 to 3%. Our POM results also indicated that as nucleating agents, the DMs promoted nucleating densities and decreased spherulitic sizes. In addition, WAXD suggeted that the addition of DMs did not induce new types of crystals. Finally, our results showed that the ductility of the PLLA was enhanced by a small amount of DMs during the PLLA crystallization process since 0.5% DMs added to the PLLA resulted in 1.4‐fold increase in the elongation at break in comparision with the neat PLLA.

    更新日期:2019-12-23
  • Fabrication and electrochemical instrumentation of redox‐active nanofiber mat for polyaniline incorporated with poly(imide sulfonate)
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-20
    Eiichi Shoji; Hiroaki Hatano; Masanori Hatashita

    In this study, we demonstrate the fabrication of an electrochemically active nanofiber mat that is a composite of high‐performance poly(imide sulfonate) (PIS) and polyaniline (PANI). First, a nonconductive nanofiber mat comprising nanofibers having diameters of ca. 300 nm was fabricated by the electrospinning of ionomeric PIS in N,N‐dimethylformamide (DMF). Then, the nanofibers were modified using PANI, which was synthesized by the oxidative polymerization of aniline, yielding an electrochemically active nanofiber mat having a diameter of ca. 350 nm. It was confirmed that PANI was successfully incorporated onto the PIS nanofiber mats by X‐ray photoelectron spectroscopy. Subsequently, we conducted electrochemical measurements of the PANI‐modified nanofiber mats using a tailor‐made attachment in which the working electrode gently comes in contact with the nanofiber mat surface. This attachment was observed to be widely useful in the cyclic voltammetry measurements related to redox‐active nanofibers. These observations are expected to contribute to the advancements in application development of the electrochemically active nanofiber mats.

    更新日期:2019-12-21
  • Fabrication of diatomite‐based microencapsulated flame retardant and its improved fire safety of unsaturated polyester resin
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-20
    Gang Chen; Yuan Yu; Zhiquan Chen; Zhongwei Chen; Changxin Li; Qingwu Zhang; Tingting Chen; Juncheng Jiang

    To achive excellent fire resistance, new microcapsule flame retardants (DMCAD and DMPPD) were prepared using 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide combined with melamine cyanurate or melamine polyphosphate as the shell material and diatomite as the core material. The successful assembly of DMCAD and DMPPD was detailed characterized by Fourier transform infrared (FT‐IR) spectra, X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Meanwhile, the flame retardancy and thermal stability of the unsaturated polyester resin (UPR)/DMCAD and UPR/DMPPD composites were also studied. The addition of DMCAD and DMPPD effectively improves the flame retardance properties of UPR, and the effect of DMPPD was better. The limiting oxygen index (LOI) of UPR/DMPPD‐3 increased by 11.6% when compared with that of UPR, and the sample achieved V‐0 rating. Moreover, the peak heat release rate (pHRR) and the total heat release (THR) rate of UPR/DMPPD‐3 were reduced by 67% and 26%, respectively. Under nitrogen condition and air condition, UPR/DMPPD showed better thermal stability and char‐forming ability from the thermogravimetric (TG) results. Residual char of the UPR composites was systematically analyzed with SEM and XPS. Finally, the flame retardant mechanism of DMPPD was proposed.

    更新日期:2019-12-21
  • Poly (diallyldimethylammonium) and polyphosphate polyelectrolyte complexes as an all‐in‐one flame retardant for polypropylene
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-19
    Lichen Zhang; Deqi Yi; Jianwei Hao

    Poly (diallyldimethylammonium chloride) (PDDA) and ammonium polyphosphate (APP) deionized chloride ions and ammonium ions by ionizing in aqueous solution respectively, then combined to form poly (diallyldimethylammonium) and polyphosphate (PAPP) polyelectrolyte complexes as an all‐in‐one flame retardant for polypropylene and its composites were characterized by Fourier transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy. One flame retardant system composed of PAPP and PP, the other flame retardant system composed of PAPP, Polyamide‐6 (PA6) and PP were tested by limiting oxygen index (LOI), UL‐94, cone calorimeter tests and thermogravimetric analysis (TGA) and compared with pure PP. The results showed that the LOI value of PP/PAPP composite can reach 27.5%, and UL‐94 V‐2 rating can be reached at 25 wt% PAPP loading. Meanwhile the cone calorimetry results displayed that the peak heat release rate (PHRR) and total heat release (THR) were reduced up to 69.3% and 22.5%, respectively, compared with those of pure PP. After adding 5 wt% PA6, the carbon source missing due to the early PAPP decomposition can be made up, and PHRR and THR can be further reduced slightly. The flame retardant mechanism of PAPP was studied by FTIR spectroscopy and X‐ray photoelectron spectroscopy. Six‐membered ring of C─N containing conjugate double bonds, cross‐linked phosphate structure formed stable, intumescent, compact char layer which greatly improved the flame retardancy of PP.

    更新日期:2019-12-20
  • Studies on electro‐optical properties of polymer matrix/LC/ITO nanoparticles composites
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-17
    Cuihong Zhang; Yuan Ge; Xiaoping Huo; Jing Xue; Kexuan Li; Yongming Zhang; Zongcheng Miao

    In this paper, polymer‐dispersed liquid crystal (PDLC) films consisting of liquid crystal (LC)/monomers/indium tin oxide (ITO) nanoparticles with good near‐infrared absorption property had been fabricated, and the influence of the ITO nanoparticles modified with 3‐methacryloxypropyltrimethoxysilane (KH570) on the PDLC films was systematically studied. First, different liquid crystal content was studied to obtain PDLC films with good electro‐optical properties. And then, various weight ratio of ITO nanoparticles was added to samples. While the content of ITO nanoparticles was increased, the saturation voltage increased and the CR decreased. Though the electro‐optical properties of PDLC samples reduced with the addition ITO nanoparticles, the near‐infrared absorption property of films was enhanced.

    更新日期:2019-12-18
  • A novel intumescent flame retardant imparts high flame retardancy to epoxy resin
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-15
    Jie Wang; Yu Guo; ShunPing Zhao; Rong‐Yi Huang; Xue‐Jun Kong

    Intumescent flame retardant (IFR) has received the considerable attention ascribed to the inherent advantages including non‐halogen, low toxicity, low smoke release and environmentally friendly. In this work, a novel charring agent poly (piperazine phenylaminophosphamide) named as PPTA was successfully synthesized and characterized by Fourier transform infrared spectra (FTIR) and X‐ray photoelectron spectroscopy (XPS). Then, a series of flame‐retardant EP samples were prepared by blending with ammonium polyphosphate (APP) and PPTA. Combustion tests include oxygen Index (LOI), vertical Burning Test (UL‐94) and cone calorimeter testing,these test results showed that PPTA greatly enhances the flame retardancy of EP/APP. According to detailed results, EP containing 10 wt% APP had a LOI value of 30.2%,but had no enhancement on UL‐94 rating. However, after both 7.5 wt% APP and 2.5 wt% PPTA were added, EP‐7 passed UL‐94 V‐0 rating with a LOI value of 33.0%. Moreover, the peak heat release rate (PHRR) and peak of smoke product rate (PSPR) of EP‐7 were greatly decreased. Meanwhile, the flame‐retardant mechanism of EP‐7 was investigated by scanning electron microscopy (SEM), thermogravimetric analysis/infrared spectrometry (TG‐IR) and X‐ray photoelectron spectroscopy (XPS). The corresponding results presented PPTA significantly increased the density of char layer, resulting in the good flame retardancy.

    更新日期:2019-12-17
  • Fabrication of durable superhydrophobic nanofibrous filters for oil‐water separation using three novel modified nanoparticles (ZnO‐NSPO, AlOO‐NSPO, and TiO2‐NSPO)
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-15
    Ali Rostami; Meghdad Pirsaheb; Golshan Moradi; Ali Ashraf Derakhshan

    Three reusable and durable superhydrophobic nanofibrous filters were prepared by dip coating the nanofibrous fabric in the three different dispersed solutions of the newly modified nanoparticles (ZnO‐NSPO, AlOO‐NSPO, and titanium dioxide [TiO2]‐NSPO). The contact angle results proved that the TiO2‐NSPO coated nanofibrous polyacrylonitrile (PAN) filter was hydrophobic with the water contact angle (WCA) of 141° while the ZnO‐NSPO and AlOO‐NSPO coated nanofibrous PAN filters were superhydrophobic with the WCA of 168° and 152°, respectively. The as‐prepared filters can be utilized as an effective martial for oil‐water separation with separation efficiency of over 98%.

    更新日期:2019-12-17
  • Molecular evolution during dynamic vulcanization of polyolefin mixtures for lead‐free thermoplastic vulcanized
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-12
    Francesco Ciardelli; Stefano Dossi; Andrea Galanti; Andrea Magri; Stefano Riolo

    The preparation process and the final properties of new thermoplastic lead‐free medium voltage (MV) insulation compounds based on the thermoplastic vulcanized (TPV) technology are reported and discussed at molecular level. The TPV MV insulation compounds were prepared starting from a peroxide curable lead free MV insulation, which is the actual market benchmark. For this reason, they were extensively investigated in comparison to the standard lead free MV insulation. The results of the dynamic vulcanization process were evaluated and related to the formulation. Now in the present paper we are reporting a detailed analysis of the molecular changes induced by the vulcanization reaction with reference to the different polymers and low molecular weight additives present in the starting mixture. The results are analyzed with reference to the used polyolefins structure with the aim to provide insights helping to relate the formulation at molecular level to the behavior of the final complex materials thus offering an useful tool to a priori design of TPVs with the desired ultimate properties.

    更新日期:2019-12-13
  • Influence of the molding angle on tensile properties of FDM parts with orthogonal layering
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-11
    Shijie Ding, Lingyu Kong, Yanjuan Jin, Jinbao Lin, Chao Chang, Huaying Li, Erqiang Liu, Haitao Liu

    Fused deposition molding (FDM) is one of the most widely used three‐dimensional (3D) printing technologies. This paper explores the influence of the forming angle on the tensile properties of FDM specimens. Orthogonal layering details were studied through experiments, theory, and finite element simulations. The stiffness and strength of the specimens were analyzed using the classical laminated plate theory and the Tsai–Wu failure criterion. The experimental process was simulated using finite element simulations. Results show that it is feasible to predict the stiffness and strength of FDM specimens using classical laminated plate theory and the Tsai–Wu failure criterion. A molding angle of 45° leads to specimens with maximized tensile properties. Numerical simulations show that changing the molding angle changes the internal stress and deformation fields inside samples, leading to FDM samples with different mechanical properties due to the orthogonal layers at different molding angles.

    更新日期:2019-12-11
  • Synthesis of tri‐aryl ketone amine isomers and their cure with epoxy resins
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-10
    Larry Q. Reyes, Buu Dao, Wouter Vogel, Johan Bijleveld, Sam Tucker, Steve Christensen, Jeffrey Wiggins, Theo Dingemans, Russell J. Varley

    Isomeric tri‐aryl ketone amines, 1,3‐bis(3‐aminobenzoyl)benzene (133 BABB), 1,3‐bis(4‐aminobenzoyl)benzene (134 BABB), and 1,4‐bis(4‐aminobenzoyl)benzene (144 BABB) are synthesized and cured with diglycidyl ether of bisphenol A and diglycidyl ether of bisphenol F in this work. Differential scanning calorimetry and near‐infrared spectroscopy reveal higher rate constants and enhanced secondary amine conversion with increasing para substitution attributed to resonance effects and the electron withdrawing nature of the carbonyl linkages. Glass transition temperatures increase from 133 BABB to 134 BABB, but decrease modestly for the 144 BABB hardener. With increasing para substitution, the flexural modulus and strength both decrease while the strain to failure increases but all BABB amines displaying higher mechanical properties than the corresponding 4,4‐diaminodiphenyl sulfone (44 DDS) networks. The thermal stability of the BABB networks is found to be modestly lower than 44 DDS, but char yields are significantly higher. Changes in thermal and mechanical properties are described in terms of molecular structure and equilibrium packing density.

    更新日期:2019-12-11
  • A novel nitrogen, phosphorus, and boron ionic pair compound toward fire safety and mechanical enhancement effect for epoxy resin
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-10
    Hao Tang, Hong Zhou

    In this work, a novel nitrogen, phosphorus and boron ionic pair compound (DTPA[AZB]), composed of a protonated flame retardant (DTPA) 6,6'‐(1,4‐phenylenebis((pyrazin‐2‐ylamino)methylene))bis(dibenzo[c,e][1,2]oxaphosphinine 6‐oxide) and a counter anion alizarin borate (AZB), has been prepared and fully characterized, AZB was synthesized by the reaction of alizarin with boric acid. DTPA was produced in two steps. First, terephthalaldehyde was condensed with aminopyrazine to form the corresponding imine. This was treated with 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) to generate DTPA. Blending with DTPA greatly reduced the flammability of epoxy resin. When the amount of DTPA added was 4%, a modified epoxy resin passed the V‐0 rating and the limiting oxygen index (LOI) reached 32.5%. With the introduction of 3% AZB into the EP/DTPA material, the LOI reached 33.5%. Simultaneously, compared with that of neat EP, the peak heat release rate and smoke production rate for EP/DTPA‐4 was decreased by 24.1% and 40.7%, respectively, and the peak heat release rate and smoke production rate for EP/DTPA[AZB]‐3 was decreased by 32.9% and 43.4%, respectively. The results indicate that AZB and DTPA show good cooperative flame retardant effects. The flame retardancy of the modified epoxy is improved with greater heat release suppression combustion of the resin. A mode of flame retardant action has been proposed based on analysis results from Py‐GC/MS for DTPA, and SEM, IR and Raman for the residual carbon from cone calorimeter and UL‐94 tests, respectively. Importantly, the tensile strength, fexural strength, and fexural modulus of the EP/DTPA[AZB] increased compared with the same properties of neat EP.

    更新日期:2019-12-11
  • Thermal degradation and pyrolysis study of brominated butyl rubber‐based damping material
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-09
    Hong‐Bing Chen, Qiu‐Si Peng, Yuan Jian, Pu‐Cheng Wang, Feng‐Shun Zhang

    This paper deals with the thermal stability and decomposition behavior of brominated butyl rubber‐based damping material (BRP). The raw materials, butyl rubber matrix (IIR) and brominated phenolic resin (PF), were also investigated as control. IIR shows one decomposition stage, while PF shows four weight loss stages. Flynn‐Wall‐Ozawa calculation indicates that BRP has thermal stability between IIR and PF. Thermogravimetric analysis–Fourier transform infrared (TGA‐FTIR) and pyrolysis–gas chromatography/mass spectrometry (GC/MS) were used to investigate the volatile products under nitrogen atmosphere. As expected, BRP shows combined thermal decomposition behavior of both IIR and PF. The degradation mechanism of BRP was proposed, which is not significantly influenced by the incorporation of PF. The application stability of BRP is worth to be noticed since the post‐cure effect, that is, the free radicals remained from vulcanization would cause additional cross‐linking when stored at 80°C to 120°C.

    更新日期:2019-12-11
  • Chitosan surface modified hydrogel as a therapeutic contact lens
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-09
    Mohammad Kazemi Ashtiani, Mojgan Zandi, Parvin Shokrollahi, Morteza Ehsani, Hossein Baharvand

    Therapeutic contact lenses have attracted significant attention during the last decades. In this study, we used chitosan‐conjugated poly(2‐hydroxyethyl methacrylate) (PHEMA) for contact lens application. We aimed to increase affinity of anionic drugs, which are used in treatment of eye diseases. In this regard, we evaluated delivery of the small molecule anionic drug, ascorbic acid from the chitosan‐conjugated PHEMA. Chitosan immobilization improves drug loading efficiency and induces sustained release of ascorbic acid. The chitosan modified hydrogel also reduces the biofouling of tear fluid components. Our results showed that surface modification by chitosan inhibits protein and bacterial deposition on the contact lens. Protein absorption analysis revealed that neat PHEMA adsorbed tear proteins at a density of 28.4 ± 4.4 μg/cm2, whereas the chitosan‐conjugated hydrogel adsorbed tear proteins at a density of 18.5 ± 1.8 μg/cm2. Moreover, the neat PHEMA bacterial adhesion had a mean CFU value of 273 ± 27. However, a significant decrease in the number of bacterial colonies was observed in the chitosan group with a CFU value of 9 ± 6.

    更新日期:2019-12-11
  • Enhanced Nucleation and Crystallization in PLA/CNT Composites via Disperse Orange 3 with Corresponding Improvement in Nanomechanical Properties
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-05
    Thevu Vu, Peyman Nikaeen, Moulero Akobi, Dilip Depan, William Chirdon

    The potential for the material property improvement through the addition of carbon nanotubes (CNTs) in composite materials is often limited due to CNT agglomeration. In this work, Disperse Orange 3 (DO3) was investigated to determine its effectiveness in dispersing CNTs in a poly (lactic acid) (PLA) matrix. First, adsorption studies of DO3 onto CNTs were performed to determine the appropriate amount of DO3 to add so that the CNT surface will be nearly saturated with DO3 while limiting the excess DO3 dissolved in the polymer. The resultant improvements in the mechanical properties were determined via nanoindentation. Highly stable dispersion of CNTs in tetrahydrofuran with DO3 was observed 72 hours after sonication. Scanning electron microscopy confirmed that DO3‐functionalized CNTs were able to separate and disperse well inside of the PLA matrix. Addition of DO3 to the nanocomposite resulted in an increase in the glass transition temperature and crystallinity of the composite due to the more effective dispersion of the nanofiller which serves as a nucleation agent. The CNTs treated with DO3 also increased the elastic modulus and hardness of the composite compared to neat PLA and untreated PLA‐CNT composites. From this study, DO3 was demonstrated to be an effective dispersing agent in the solvent and the PLA matrix which allowed for enhanced crystallization and improved nanomechanical properties in the resultant composite.

    更新日期:2019-12-11
  • Fabrication of electrospun polyethersulfone/titanium dioxide (PES/TiO2) composite nanofibers membrane and its application for photocatalytic degradation of phenol in aqueous solution
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-05
    Masoume Ehsani, Abdolreza Aroujalian

    The main objective of this research is to use the photocatalytic properties of PES/TiO2 nanofibers membranes to remove the phenol as a toxic pollutant in various effluents. The uniform fibers in terms of minimum bead formation and fibers diameter were fabricated. Therefore, more TiO2 catalysts are on the surface of the fibers which increase the active surface area of nanoparticles and consequently improve the phenol degradation efficiency. The effects of TiO2 concentration on hydrophilicity, mechanical properties, porosity, mean pore size, and water flux of membranes were studied. The PES/TiO2 nanofibers were evaluated for phenol degradation under UVA irradiation through a transparent membrane module. The amount of removable phenol was analyzed with high‐performance liquid chromatography. Central composite design was used as a statistical experimental design. Finally, the effect of TiO2 content in nanofibers and initial phenol concentrations were investigated as well as pH values in synthetic wastewater, on phenol degradation. The results from analysis of variance (ANOVA) analysis indicated that TiO2 content in nanofibers was the most important and effective parameter on phenol degradation. It was also presented that there is no significant interaction between parameters so that the effect of each parameter was investigated separately. Maximum phenol degradation was 43.0 ± 0.3% and found under conditions of TiO2 content, initial phenol concentration, and pH value of 8%, 120 ppm, and 7, respectively.

    更新日期:2019-12-11
  • Chitosan‐modified graphene oxide as a modifier for improving the structure and performance of forward osmosis membranes
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-05
    Chun‐Hui Du, Xin‐Yi Zhang, Chun‐Jin Wu

    Chitosan (CS) with good hydrophilicity and charged property was used to modify graphene oxide (GO), the obtained GO‐CS was used as a novel modifier to fabricate thin film composite forward osmosis (FO) membranes. The results revealed that the amino groups on CS reacted with carboxyl groups on GO, and the lamellar structure of the GO nanosheets was peeled off by CS, resulting in the reducing of their thicknesses. The GO‐CS improved the hydrophilicity of polyethersulfone (PES) substrate, and their contact angles decreased to 64° with the addition of GO‐CS in the substrate. GO‐CS also increased the porosity of the substrate and surface roughness of FO membrane, thereby optimizing the water flux and reverse salt flux of FO membrane. The average water flux of the FO membrane reached the optimal flux of 21.34 L/(m2 h) when GO‐CS addition was 0.5 wt%, and further addition of GO‐CS to the substrate would decrease the water flux of FO membrane, and the reverse salt flux also decreased to the lowest value of 2.26 g/(m2 h). However, the salt rejection of the membrane increased from 91.4% to 95.1% when GO‐CS addition increased from 0.5 to 1.0 wt% under FO mode using 1 mol/L sodium chloride (NaCl) solution as draw solution (DS). In addition, high osmotic pressure favored water permeation, and at the same concentration of DS, magnesium chloride (MgCl2) exhibited better properties than NaCl. These results all suggested that GO‐CS was a good modifier to fabricate FO membrane, and MgCl2 was a good DS candidate.

    更新日期:2019-12-11
  • Poly(propylene carbonate)/poly(3‐hydroxybutyrate)‐based bionanocomposites reinforced with cellulose nanocrystal for potential application as a packaging material
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-05
    Guo Jiang, Li Yu, Mengdi Zhang, Feng Wang, Shuidong Zhang

    Poly(propylene carbonate) (PPC) is an aliphatic polycarbonate synthesized from carbon dioxide and propylene oxide. Poly(3‐hydroxybutyrate) (PHB) is a type of thermoplastic polyester produced by biological fermentation. The blending of PHB with PPC can effectively enhance the mechanical properties and barrier properties of PPC. Bionanocomposites of PPC/PHB enhanced by cellulose nanocrystal (CNC) are prepared via a two‐step process using polyethylene glycol as a carrier. Results show that the oxygen barrier properties of the composites increased with the increase of the CNC content. When the CNC content is 1 wt%, the oxygen barrier performance increases nearly 18 times. The assumed model can predict the barrier performance of composites with the combined influence of morphology and CNC distribution. This will make PPC/PHB/CNC nanocomposites a very promising degradable material for food packaging application.

    更新日期:2019-12-11
  • Preparation, oil adsorption behavior, and mechanism of micro/nanofibrous polycaprolactone membrane prepared through solution blow spinning
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-05
    Tingting Zhang, Ruiting Yang, Xiaohui Zhang, Xueqiong Yin, Hua Tian, Li Zhu

    In this paper, biodegradable polycaprolactone (PCL) was used as the raw material to prepare micro/nanofibrous polycaprolactone membrane (PCLM) through solution blow spinning (SBS) technology. The effects of spinning conditions (distance, gas pressure, and spinning solution concentration) on PCLM structures were investigated. The obtained membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, water contact angle, and thermogravimetric analysis instrument. The oil adsorbency and reusability of PCLM were measured. The oil adsorption capacity of PCLM for motor oil, peanut oil, and diesel oil was 15.93, 14.81, and 12.86 g·g−1, respectively. After 10 times of reuse, the adsorption capacity for motor oil, peanut oil, and diesel oil could still remain at about 80% of the first cycle. The kinetic and thermodynamic studies showed that the adsorption conformed to the first‐order kinetic model and Freundlich model. Thermodynamic parameters for oil adsorption ΔGθ, ΔHθ, and ΔSθ indicated the oil adsorption of PCLM was a spontaneous and physisorption process.

    更新日期:2019-12-11
  • Simulation of crystallization evolution of polyoxymethylene during microinjection molding cycle
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-04
    Benayad Anass, Boutaous M'hamed, El Otmani Rabie, El Hakimi Abdelhadi, Touache Abdelhamid, Kamal R. Musa, Derdouri Salim, Refaa Zakariaa, Siginer Dennis

    A mathematical model coupled with a numerical investigation of the evolving material properties due to thermal and flow effects and in particular the evolution of the crystallinity during the full microinjection molding cycle of poly (oxymethylene) POM is presented using a multi‐scale approach. A parametric analysis is performed, including all the steps of the process using an asymmetrical stepped contracting part. The velocity and temperature fields are discussed. A parabolic distribution of the velocity across the part thickness, and a temperature rise in the thin zone toward the wall have been obtained. It is attributed to the viscous energy dissipation during the filling phase, but also to the involved characteristic times for the thermal behavior of the material. Depending on the molding conditions and the locations within the micro‐part, different evolution of crystallization rates are obtained leading to at least three to five morphological layers, obtained in the same part configuration of a previously work, allowing a clear understanding of the process‐material interaction.

    更新日期:2019-12-11
  • Synthesis of a novel phosphate‐containing highly transparent PMMA copolymer with enhanced thermal and flame retardant properties
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-04
    Baoping Yang, Lurong Wang, Yongliang Guo, Yabin Zhang, Niannian Wang, Jinfeng Cui, Junhong Guo, Li Tian

    A novel poly(methyl methacrylate) (PMMA)‐based copolymer (PMMA‐co‐BDPA) rich in aromatic rings was synthesized via radical copolymerization between a phosphorus‐containing acrylic monomer (BDPA) and methyl methacrylate (MMA). UV‐vis spectroscopy demonstrated that the copolymer had high transparency. Thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC) were used to test the thermal properties of the composites. Additionally, the PMMA‐co‐BDPA‐15 copolymer exhibited a 23% increase in the limited oxygen index (LOI) value. A cone calorimeter test indicated that the peak heat release rate (pk‐HRR) of PMMA‐co‐BDPA was reduced by 29.2% compared with that of pure PMMA, and the carbon yield of burning was obviously increased. The combined test results demonstrated that the prepared copolymer material had good transparency, thermal stability, and flame retardancy.

    更新日期:2019-12-11
  • Bioinspired preparation of regular dual‐level micropillars on polypropylene surfaces with robust hydrophobicity inspired by green bristlegrass leaves
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-04
    Heng Xie, Wen‐hua Xu, Ting Wu

    The fine microstructure on the natural green bristlegrass leaf of Setaria viridis (L.) Beauv, which exhibits a contact angle (CA) of 155°±2° and a rolling angle (RA) of 79°±2°, is carefully observed. Based on the understanding of the underlying mechanisms for superhydrophobicity and moderate surface adhesion, an efficient replica molding strategy is proposed for mimicking the microstructures on green bristlegrass leaf surface to polypropylene (PP) surfaces. The bioinspired PP replica with dual‐level micropillars are molded by using the unitized template of steel Meshes A and B. Interestingly, the PP replica inherits both hydrophobicity and adhesion of the natural leaf. Furthermore, the PP replica can stabilize its hydrophobic state under a 980 Pa external pressure, which is attributed to the composite Cassie‐Wenzel mixed wetting state on the microstructured interface. The CA comparatively goes down and RA increases, resulting in superhydrophobic surface with moderate adhesion on the bioinspired surface. Hence, the microstructures and hydrophobicity are successfully replicated to the PP surface by only using the low cost, available and reliable steel meshes in the bioinspired replica molding process.

    更新日期:2019-12-11
  • Great improvement of low‐temperature impact resistance of isotactic polypropylene/ethylene propylene diene monomer rubber blends by traces of carbon nanotubes and β‐nucleating agents
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-04
    Qian Fan, Jinghan Zhang, Zhiqiang Wu, Song Yang, Yanhui Chen, Ying Lu, Qiuyu Zhang

    In this work, a considerable low‐temperature toughness enhancement of isotactic polypropylene (iPP) was achieved by adding 30 wt% ethylene propylene diene monomer rubber (EPDM) as well as traces of β‐nucleating agent (β‐NAs) and carbon nanotubes (CNTs). The impact strength of the iPP/30 wt% EPDM blend with 0.1 wt% β‐NAs reached 6.57 kJ/m2 at −20°C, over 2.5 times of pure iPP. A slightly improved impact strength was further found in the β‐nucleated iPP/30 wt% EPDM at the presence of 0.05 wt% CNTs. The presence of traces of CNTs, β‐NAs, and EPDM displayed synergistic low‐temperature toughness reinforcement effect on the iPP blends. The underlying toughening mechanism was attributed to the formation of a great amount of voids and plastic deformation of iPP matrix affected by CNTs, β‐NAs, and EPDM. Our work provided a feasible strategy to significantly increase the low‐temperature toughness of iPP.

    更新日期:2019-12-11
  • The research on multi‐responsive azobenzene block copolymer and its self‐assembly behavior
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-02
    Ying Cao, Jie Cao, Jiatian Zhang, Dandan Zhang, Meng Li, Yiting Xu, Kaibin He, Guorong Chen, Conghui Yuan, Lizong Dai

    The azobenzene‐based amphiphilic copolymers have drawn significant attention as a kind of multi‐responsive smart materials. The demand on deeper investigation of how the azobenzene group influences the micelles formation and light‐responsive behavior on molecular level is very urgent. In this article, multi‐responsive block copolymers, poly (acrylic acid)‐block‐poly[4'‐[[(2‐Methacryloyloxy)ethyl]ethylainino]azobenzene‐co‐poly (ethylene glycol) methyl ether methacrylate] (PAA‐b‐P (AzoMA‐co‐PEGMA)), with pH‐, light‐ and reduction‐responsiveness were synthesized by the monomers of AzoMA, PEGMA and acrylic acid via reversible addition‐fragmentation chain transfer polymerization (RAFT). The amphiphilic block copolymer presented aggregation‐induced emission effect, and it was pH, light, and reduction responsive. The results showed that the micelle size decreased with the decreasing of pH within a certain range. However, the particle size of micelles increased significantly when the pH was 4. Once adding reduction agent, the micelles were disassembly. Fluorescent molecule of Nile red was selected as a hydrophobic guest molecule to study the properties of encapsulating and releasing abilities of block copolymer micelles for guest molecules. The results showed that the loading capacity of three kinds of copolymer micelles was closely related to the aggregates formed by the hydrophobic block, mainly azobenzene block. Besides, the block copolymer micelles could release a certain amount of Nile red under the irradiation of UV light, the reduction with Na2S2O4 as reductant, and the exposure to alkaline environment. The mechanism of how the different status of azobenzene group influenced the self‐assembly and multi‐responsive behavior was explored on molecular level.

    更新日期:2019-12-11
  • Flame‐retardant poly (ethylene terephthalate) enabled by a novel melamine polyphosphate nanowire
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-12-01
    Teng Li, Shuai Li, Tongjun Ma, Yi Zhong, Linping Zhang, Hong Xu, Bijia Wang, Xiaofeng Sui, Xueling Feng, Zhize Chen, Zhiping Mao

    A novel strategy was developed for the preparation of melamine polyphosphate (MPP) nanowires to achieve a superior flame‐retardant poly (ethylene terephthalate) (PET). Thanks to the well‐designed nanostructure, the prepared MPP nanowires exhibited great thermal stability and flame retardance. Herein with incorporation of only 1‐wt% MPP nanowires (PET/FR1.0 nanocomposite), the limiting oxygen index (LOI) value was dramatically increased to 29.4% from 20.5%, showing self‐extinguishing behavior. Moreover, PET/FR1.0 nanocomposite passed V‐0 UL‐94 rating in the vertical combustion test. However, PET containing 5‐wt% commercial MPP powder (PET/FRC5.0) only showed a LOI of 27.9% and ignited the absorbent cotton with flammable melt‐droplets. Cone results also presented that introducing 1‐wt% MPP nanowires brought about a crucial decrease in fire hazard of PET, for instance, 11.1% and 7.7% maximum reduction in heat release rate and total heat release, respectively. Thermogravimetric analysis/infrared spectrometry (TG‐FTIR) result indicated that the main pyrolysis volatiles generated from PET degradation including benzoic acid, aromatic compounds, and carbon dioxide were apparently suppressed after introducing MPP nanowires into PET matrixes, suggesting the outstanding obstructing effect of graphited char residue formed in the combustion. This enhanced flame retardancy rooting in addition of MPP nanowires can be attributed to the combined dilution effect in gaseous phase and catalytic carbonization effect in condensed phase.

    更新日期:2019-12-11
  • Electrospun polyethylene terephthalate (PET) nanofibrous conduit for biomedical application
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-28
    Sahar Jafari, Seyyedeh Sahar Hosseini Salekdeh, Atefeh Solouk, Maryam Yousefzadeh

    Nanostructured biomaterials have great potential in the field of biomedical engineering. Efforts for treatment of cardiovascular diseases focused on introducing vascular substitutes that are nonthrombogenic and have long‐term patency, but still there is not any perfect replacement for clinical use. In this study, nanostructure tubes of a commonly known biocompatible polymer, polyethylene terephthalate (PET), were prepared via electrospinning process using small diameter mandrel as a collector with two different speeds. The nanofibers (NFs) morphologies' physical and mechanical properties were investigated according to scanning electron microscope (SEM), water contact angle (WCA), porosity measurement, differential scanning calorimetry (DSC), and tensile test. Finer NFs, more percentage of crystallinity, and superior mechanical properties were observed for samples prepared by higher speed mandrel. Since both samples stimulated platelet adhesion and activation, further surface modification with sodium nitrate as nitric oxide (NO) donor was done using two different approaches: dip‐coating and electrospraying. The modified NFs were evaluated via SEM, WCA, tensile test, platelets, and cell adhesion. The results showed more hydrophilicity, reduction in platelet adhesion, and improved blood compatibility for eNO‐HS (electrosprayed NO for higher collector speed) compared with other samples implying the promising potential of this fabrication and modification technique for improving PET‐based cardiovascular substitutes.

    更新日期:2019-12-11
  • Preparation of polyimide/BaTiO3‐nanocrystal hybrid thin films and their dielectric property
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-28
    Fengmei Cheng, Hao Li, Haidong Li

    High dielectric constant is highly desirable in capacitors and memory devices. In this work, oleic acid (OA)‐capped BaTiO3 nanocrystals were synthesized by a two‐phase approach. Polyimide (PI)/BaTiO3‐nanocrystal composite thin films with high dielectric constant have been successfully fabricated. The morphologies and dielectric properties of the hybrid films were exploited. The results showed that BaTiO3 nanocrystals can be uniformly dispersed in the PI thin films owing to the surface modification of OA‐capped BaTiO3 nanocrystals. It was found that the dielectric constant of composite film varies with the volume fraction of BaTiO3 nanocrystals and sintering temperatures and reaches a maximum value of 44.1, which is around 13 times higher than that of pristine PI thin film (3.2). These results demonstrated that PI/BaTiO3‐nanocrystal composite films have considerable application potential in microelectronic fields.

    更新日期:2019-12-11
  • Influence of fused deposition modeling parameters on the mechanical properties of ABS parts
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-19
    Carlos M.S. Vicente, Tomás S. Martins, Marco Leite, António Ribeiro, Luís Reis

    This work aims to determine the influence of fused deposition modeling (FDM) printing parameters on the mechanical properties of parts fabricated on an Ultimaker2 printer with acrylonitrile butadiene styrene (ABS). The effect of several parameters such as interlayer cooling time (ILCT), nozzle diameter, infill density, raster angle and layer thickness on the ultimate tensile strength, yield strength, and elastic modulus of produced parts was evaluated. Two independent studies were conducted: a first study dedicated to the ILCT and a second study where the influence of other parameters was evaluated through a design of experiments (DoE) approach. Both studies were carried out through the execution of standard tensile tests. The statistical analysis of tensile tests results was processed with the ANOVA methodology. The obtained results indicate that a reduced ILCT improves the tensile strength of parts. It is shown that nozzle diameter and infill density are the parameters that most influence the mechanical properties of ABS, with the upper range selected values improving the studied mechanical properties. The raster angle configuration of (−45o/45o) benefits UTS and yield strength of ABS samples. Interactions of nozzle diameter on layer thickness were detected. It was observed that smaller layer thickness promotes a higher elastic modulus and UTS; however, for thinner layers (0.06‐0.10 mm), no significant differences were found on strength of samples due to potential high distortion levels.

    更新日期:2019-12-11
  • Effect of different ionic layered compounds decorated with zinc hydroxystannate on flame retardancy and smoke performance of epoxy resin
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-17
    Wenzong Xu, Wu Li, Xiaoling Wang, Xuemin Zhang, Zihao Cheng

    ZHS@ Mg‐Al‐LDH and ZHS@α‐ZrP hybrid materials were prepared by electrostatically loading zinc hydroxystannate (ZHS) on the layered compounds (Mg‐Al‐LDH and α‐ZrP) in this work. With the addition of 2 wt% of the two hybrid materials to epoxy resin (EP), respectively, the fire hazard of EP and its composites were investigated. The limiting oxygen index (LOI) of ZHS@ Mg‐Al‐LDH/EP composite increased by 19.0% compared with pure EP, while its peak heat release rate (PHRR), total heat release rate (THR), and peak smoke release rate (SPR) decreased by 48.2%, 20.8%, and 21.6%, respectively, evidenced by the results of the LOI test and cone calorimetry test (CCT). The LOI of ZHS@α‐ZrP/EP composite increased by 20.4%, and its PHRR, THR, and SPR decreased by 47.7%, 21.4%, and 27.1%, respectively. Both hybrid materials showed prominent flame retardant and smoke suppressing properties. In addition, through the analysis of the TG‐IR and Raman spectrum of residual char, the specific mechanism of flame retardance and smoke suppression was explored.

    更新日期:2019-12-11
  • The effect of OCoAl‐LDH and OCoFe‐LDH on the combustion behaviors of polyvinyl chloride
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-17
    Zehua Gao, Lihong Lu, Congling Shi, Xiaodong Qian

    The effects of the modified layered double hydroxide (LDH) of Co/Al (OCoAl‐LDH) and the modified LDH of Co/Fe (OCoFe‐LDH) on the combustion behaviors of polyvinyl chloride (PVC) during pyrolysis processes were compared and investigated. The thermal degradation and combustion behavior of the PVC composites were investigated by thermogravimetric analysis (TGA), microscale combustion calorimetry (MCC), and cone calorimetry (CONE). The results indicate that the incorporation of LDHs brought about the improved thermal stability and reduced heat release of PVC composites at a high temperature. The smoke‐suppression properties of the composites are investigated by steady‐state tube furnace (SSTF), and the results indicated that the toxic gases such as CH4, CO, and NxO were inhibited by both of the two LDHs, but the OCoFe‐LDH has a better effect on the smoke suppression. Subsequently, the char layer was investigated by scanning electron microscopy–energy‐dispersive spectrometry (SEM‐EDS) and Raman analysis. The results indicate that the LDHs can promote the dechlorination of PVC during the thermal oxidation process and can inhibit the production of HCl in inert gas. Generally, OCoAl‐LDH and OCoFe‐LDH can be potential catalysts for waste disposal and can improve the fire safety of PVC.

    更新日期:2019-12-11
  • Effect of nitrogen plasma treatment on the crystallinity and self‐bonding of polyetheretherketone (PEEK) for biomedical applications
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-17
    Mariangela Fedel, Victor Micheli, Martin Thaler, Firas Awaja

    Polyetheretherketone (PEEK) is a thermoplastic material with outstanding properties and high potential for biomedical applications, including hermetic encapsulation of active implantable devices. Different biomedical grade PEEK films with initial degree of crystallinity ranging from 8% to 32% (with or without mineral filling) were inspected. PEEK surfaces were treated with nitrogen RF plasma and the effects on materials crystallinity and self‐bonding were evaluated. In particular, the relationship between auto‐adhesive properties and crystalline content of PEEK before and after plasma treatment was examined.

    更新日期:2019-12-11
  • Preparation of a biodegradable superabsorbent polymer and measurements of changes in absorption properties depending on the type of surface‐crosslinker
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-16
    Yoo Jin Kim, Seok Ju Hong, Woo Seung Shin, Yong Rok Kwon, Seung Ho Lim, Hae Chan Kim, Jung Soo Kim, Jin Woong Kim, Dong Hyun Kim

    A superabsorbent polymer (SAP) is a special polymer material that can absorb up to 500 times its own weight of pure water, but has a problem that it does not biodegrade itself and cause environmental pollution. Therefore, we aim to prepare a biodegradable SAP by using biomass‐based IA. The SAP must be able to retain absorbed water and absorb water under a given pressure. We have carried out studies to improve the surface hardness of the SAP to enhance absorption of water under a given pressure by surface‐crosslinking. Four types of surface‐crosslinkers, ethylene glycol diglycidyl ether (EGDGE), ethylene carbonate (EC), 1,4‐butanediol (BD), or glycerol, were used. We confirmed the water absorption capacity of the SAP by measuring its centrifuge retention capacity (CRC) and absorbency under load (AUL). The structural characteristics of the SAP were confirmed by attenuated total reflection (ATR) and X‐ray photoelectron spectroscopy (XPS), and the surface characteristics were confirmed by scanning electron microscopy (SEM).

    更新日期:2019-12-11
  • Fabrication of high thermal stable cured novolac/Cloisite 30B nanocomposites by chemical modification of resin structure
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-15
    Fatemeh Javanbakht, Bahareh Razavi, Mehdi Salami‐Kalajahi, Hossein Roghani‐Mamaqani, Masoud Ommati

    Cloisite 30B as a modified kind of nanoclay was utilized for the formation of 3D network based on novolac resin with high thermal stable properties. Two types of phenolic resins including neat novolac (NR) and modified novolac resin were used to create a compatible matrix with nanoclay. For this purpose, NR modified with (3‐chloropropyl)triethoxysilane (CPTES) to form SiNR. For improvement of thermal behaviors, Cloisite 30B was dispersed in matrix via ultrasonic waves and cured with hexamethylenetetramine (HMTA) to form 3D network. X‐ray diffraction (XRD) analysis was used to measure the d‐spacing in intercalated systems and results indicated the optimum amount of clay for appropriate thermal properties. Investigation of the thermal properties of the samples by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the presence of Cloisite 30B in matrix resulted in much higher thermal stability and char yield with respect to modification of novolac resin originated from formation of 3D Si–O–Si network. Also, cured modified resin and its nanocomposites showed much higher thermal stability than cured NR and its nanocomposites. Such nanocomposite materials with high thermal stability have potential applications in advanced fields such electronic, industrial molds, coatings, adhesives, and aerospace composites.

    更新日期:2019-12-11
  • Synergistic effect of graphene oxide nanoplatelets and cellulose nanofibers on mechanical, thermal, and barrier properties of thermoplastic starch
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-15
    Hessam Ramezani, Tayebeh Behzad, Ruhollah Bagheri

    In recent years, because of the limited availability of oil resources and the increasing concerns regarding environment protection, much attention has been drawn to produce packaging films based on degradable biopolymers instead of synthetic polymers. On the other hand, because of the high costs of oil extraction, raw materials and film production, and disposing of the waste products of synthetic films, the need to replace these films with less pollutant and more cost‐effective films is growing globally. In this study, to answer the need for replacing synthetic polymer films, nanocomposite films based on thermoplastic starch reinforced with cellulose nanofibers and graphene oxide nanoplatelets were produced and characterized. The results implied that the synergistic effect of cellulose nanofibers and graphene oxide nanoplatelets has played an important role in improving the mechanical properties of the films. The results showed that with the addition of cellulose nanofibers and graphene oxide nanoplatelets, the tensile strength and elastic modulus of starch film were increased from 3 and 32 MPa to 13 and 436 MPa, which corresponds to 438% and 1435% improvement, respectively. In addition, the oxygen permeability resistance and the water vapor transmission for samples containing 3 wt% of graphene oxide nanoplatelets was decreased by 78% and 30% compared with the thermoplastic starch film, respectively. The permeability coefficient of the samples containing 3 wt% graphene oxide nanoplatelets for oxygen, nitrogen, and carbon dioxide have proved to be 0.051, 0.054, and 0.047 barrer, which shows that these films can perform well as packaging films.

    更新日期:2019-12-11
  • Natural rubber–based composites filled with bioglasses from a CaO‐SiO2‐P2O5‐Ag2O system. Effect of Ag2O concentration in the filler on composite properties
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-15
    Abdullah G. Al‐Sehemi, Ahmed A. Al‐Ghamdi, Nikolay T. Dishovsky, Lachezar N. Radev, Irena K. Mihailova, Petrunka A. Malinova, Nikolay T. Atanasov, Gabriela L. Atanasova

    Bioactive glass was first synthesized by L. Hench in 1971. There are many studies on the properties of several metals and metal ions dopants used in the SiO2‐CaO‐P2O5 system of bioglasses, such as Ag, Cu, Zn, and Fe. A number of authors have carried out research related to the influence of silver oxide on the properties of bioglasses. However, publications on the properties of elastomer‐based composites containing bioactive glasses are relatively scarce. We have not found in the literature studies discussing how silver oxide concentration in bioglasses of the CaO‐SiO2‐P2O5‐Ag2O system affects the significant properties of a natural rubber biocomposite. In this regard, the purpose of the present work is to investigate the aforementioned influence on the properties of this type of composites, namely, vulcanization, physicomechanical, thermal, dynamic, dielectric, electric, and thermoconductive characteristics. We have established those parameters of the composites to be impacted considerably by both degree of filling with bioglass and the silver oxide content in the latter. The improvement in the composites thermostability and some of their physicomechanical performance is the most significant. The volume resistance decreases, and the thermal conductivity coefficients increase. Results from scanning electron microscopy and energy‐dispersive X‐ray (EDX) analyses have confirmed the influence of silver oxide initially on the phase composition of the bioglass, hence on the properties of the biocomposites through changes in the bioglass used as filler. The dielectric characteristics of some of the biocomposites suggest that they can be used as substrates and insulating layers in flexible antennas for short‐range wireless communications.

    更新日期:2019-12-11
  • A feasible strategy to constructing hybrid conductive networks in PLA‐based composites modified by CNT‐d‐RGO particles and PEG for mechanical and electrical properties
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-14
    Shikui Jia, Demei Yu, Yan Zhu, Xiaolong Su, Zhong Wang, Ligui Chen

    Carbon nanotubes (CNTs) and reduced graphene oxide (RGO) were successfully assembled by chemical reaction to obtain CNT‐d‐RGO particles. Then, a home‐made dynamic impregnating device was used to prepare hybrid CNT‐d‐RGO/polyethylene glycol (PEG). Next, the different modifiers, including CNTs, GO, CNT‐d‐RGO, PEG, and CNT‐d‐RGO/PEG, were, respectively, added into poly‐(lactic acid) (PLA) matrix via melt‐compounding. The dispersed morphology for these different modifiers within the PLA matrix was confirmed by SEM and TEM observations. Especially, compared with the identical weight ratio of CNT‐d‐RGO, the hybrid CNT‐d‐RGO/PEG within the PLA matrix exhibited an excellent exfoliated and interconnected networks morphology. Moreover, compared with pure PLA, not only the crystallinity of all PLA‐based composites notably improved, but half‐crystallization time was also shortened. Furthermore, despite the addition of different modifiers, the crystal form of PLA‐based composites remained unchanged. Noticeably, compared with those of pure PLA, the tensile stress, strain, and modulus of PLA composite added with CNT‐d‐RGO/PEG increased by 29.4%, 4.1%, and 56.1%, respectively, and the V‐notch impact strength slightly improved. In addition, compared with pure PLA, volume resistivity of the PLA composite added with 1 wt% CNT‐d‐RGO/PEG decreased by 93.1%, and its volume conductivity increased by five orders of magnitude.

    更新日期:2019-12-11
  • Effect of Pickering emulsion on the mechanical performances and fracture toughness of epoxy composites
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-14
    Shuiping Li

    The improvement of mechanical properties and toughness of nanoparticles for epoxy composites was mostly dependent on the disperse state of nanoparticles in epoxy matrices. When the content of nanoparticles was higher than a threshold value, it was easy to aggregate and then affect the improvement effect. Pickering emulsion was prepared using SiO2 nanoparticles as emulsifier and functional monomer as oil phase. The influence of Pickering emulsion on the curing process was investigated. The effect of Pickering emulsion on the mechanical properties, toughness, and glass transition temperature (Tg) was studied. Impact and tensile fracture surface were observed by scanning electron microscopy (SEM). Results from differential scanning calorimeter (DSC), tensile, impact, and fracture toughness tests are provided. The results indicated that the introduction of Pickering emulsion can eliminate the residual stress and accelerate curing reaction. Epoxy composites were capable of increasing tensile strength by up to 29.9%, impact strength of three‐fold, fracture toughness of 35%, and Tg of 20.7°C in comparison with the reference sample. SEM images showed that SiO2 nanoparticles exhibit a good dispersion in epoxy matrix. The increases in mechanical properties, toughness, and Tg of epoxy composites were attributed to the “Second Phase Toughness” mechanism.

    更新日期:2019-12-11
  • Biocompatible fluorescent polyamine‐based cyclophosphazene hybrid nanospheres for targeted cell imaging
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-13
    Raheel Akram, Anila Arshad, Sami Ullah Dar, Majid Basharat, Wei Liu, Shuangkun Zhang, Zhanpeng Wu, Dezhen Wu

    Fluorescent nanoprobes are highly desirable toolkit for bioimaging applications. This study reports the first example for the synthesis of a nontoxic prototypical fluorescent organic compound 2‐benzo[d]thiazol‐2‐yl)‐3‐(2‐chloro‐4‐(dimethylamino)phenyl)acrylonitrile (BCA) and its entrapment into the poly[cyclotriphosphazene‐co‐polyethyleneimine] cross‐linked (PCPEI) nanospheres named as BCA@PCPEI for targeted cell imaging application. The as‐prepared BCA@PCPEI nanospheres were thoroughly characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and phosphorus‐31 nuclear magnetic resonance (31P‐NMR) analyses. The surface functional analysis of the nanospheres was performed by X‐ray photoelectron spectroscopy (XPS), which proves that the content ratios of elements belong to the precursors concentrations. The as‐prepared nanospheres displayed emission at 606 nm with bright orange fluorescence at any concentration. Moreover, the nanospheres were also less cytotoxic and maintained remarkable cell viability up to 100 μg/mL. Owing to the fluorescence with higher emission, this material has shown excellent cell imaging performance with better targeting ability to HeLa cells.

    更新日期:2019-12-11
  • Injectable hydrogels for targeted delivering of therapeutic molecules for tissue engineering and disease treatment
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-12
    Rukhshona Mavlyanova, Rufeng Yang, Tao Tao, Md Aquib, Samuel Kesse, Mily Bazezy Joelle Maviah, Kofi Oti Boakye‐Yiadom, Muhammad Asim Farooq, Bo Wang

    Hydrogels are cross‐linked three‐dimensional polymeric networks that play a vital role in solving the pharmacological and clinical limitations of the existing systems due to their unique physical properties such as affinity for biological fluids, tunable porous nature, high water content, ease of preparation, flexibility, and biocompatibility. Hydrogel also mimics the living natural tissue, which opens several opportunities for its use in biomedical areas. Injectable hydrogel allows temporal control and exceptional spatial arrangements and can offset hitches with established hydrogel‐based drug delivery systems. Here, we review the recent development of injectable hydrogels and their significance in the delivery of therapeutics such as cells, genes, and drug molecules and how these innovatory systems can complement the current delivery systems.

    更新日期:2019-12-11
  • Non‐oxidized graphene/elastomer composite films for wearable strain and pressure sensors with ultra‐high flexibility and sensitivity
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-12
    Qingshi Meng, Zhiwen Liu, Rui Cai, Sensen Han, Shaowei Lu, Tianqing Liu

    It remains challenging to prepare wearable strain and pressure sensors with excellent mechanical properties, ultra‐high flexibility and sensitivity. Electrically conductive graphene platelets (GnPs) with high structural integrity are used in making a composite film fabricated using robust fabrication techniques. The gauge factor for the strain is up to 100 at 0%‐5% strain and 50 at 5%‐30% strain, and the sensitivity to pressure is 2.7×10‐2 kPa‐1 between 0 and 10 kPa and 1.5×10‐4 kPa‐1 between 300 and 1000 kPa. In addition, the flexible sensor demonstrates good repeatability and durability after 1000 cycles of tensile and compression tests. The flexible sensor has fast response ability and a wide operating temperature range, suggesting the excellent response to temperature. The flexible sensor is applied in monitoring several human motions as a wearable device with high accuracy. The ability to detect strain, pressure and temperature of the flexible sensor extends its applications to multifunctional wearable devices.

    更新日期:2019-12-11
  • Novel synthesis of copper oxide on fabric samples by cathodic cage plasma deposition
    Polym. Adv. Technol. (IF 2.162) Pub Date : 2019-11-11
    Fernanda Fernades, Edglay Rocha Filho, Ivan Souza, Igor Nascimento, Rômulo Sousa, Edalmy Almeida, Michele Feitor, Thércio Costa, Muhammad Naeem, Javed Iqbal

    The fabrics with copper or copper oxide deposition are of considerable interest because of exceptional antibacterial properties, which are useable in medical, textiles, and hygiene applications. Unfortunately, the conventional techniques take long processing time, complex equipment, and combination of several processing steps (nanoparticles synthesis and their deposition on fabrics). In this novel study, cathodic cage plasma deposition assisted with copper cathodic cage is used for the synthesis of the copper oxide on polyester and polyamide fabrics. For the enhancement of synthesis efficiency, the effect of cathodic cage lid thickness is also investigated. The samples are assessed by using scanning electron microscopy, elemental dispersive spectroscopy, and X‐ray photoelectron spectroscopy. It is found that using cathodic cage plasma deposition, fabrics can be successfully synthesized by the copper oxide with comparatively small treatment time, cost‐effectively, and environmentally friendly. Interestingly, cathodic cage plasma treatment is already proved to be working effectively on industrial scale; thus, it is predicted to be of noteworthy importance for fabrics processing on large‐scale garments manufacturing and hospitals.

    更新日期:2019-12-11
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