Open Access Published by De Gruyter

Volume 17 Issue 5

Issue of e-Polymers

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Contents
Journal Overview

Publicly Available August 25, 2017

Frontmatter

Page range: i-iii

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Publicly Available August 25, 2017

In this Issue

Page range: iv-vii

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Open Access March 16, 2017

Elastic recovery of polyamide 6 matrix nanocomposites and their basalt fiber co-reinforced hybrids

László Mészáros

Page range: 349-354

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Abstract

Abstract: The improved elastic recovery and a wider range of linear elastic behavior of multiscale hybrid polyamide 6 composites are demonstrated in this study. For the composites, basalt fiber (BF) was used as microsized, and multiwalled carbon nanotubes and surface-treated montmorillonite (MMT) as nanosized reinforcement. The materials were melt compounded, and then specimens were injection molded. To prove increased elastic behavior, a relatively simple and fast cyclic measurement method was applied, where the load was increased in each cycle and 30 s of relaxation time was allowed after unloading. The results showed that both micro- and nanoparticles can broaden the range of the elastic behavior of the polyamide 6 significantly, which is reflected in increased elastic recovery and decreased plastic deformation compliance. Nano- and microsized reinforcing materials also produce a synergistic effect, which can be explained with the physical cross-linking of the nanoparticles.

Open Access April 10, 2017

Bio-based chitosan/PVdF-HFP polymer-blend for quasi-solid state electrolyte dye-sensitized solar cells

Wan Zaireen Nisa Yahya, Wong Theen Meng, Mehboob Khatani, Adel Eskandar Samsudin, Norani Muti Mohamed

Page range: 355-361

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Abstract

Dye-sensitized solar cells (DSSCs) have emerged to become one of the most promising alternatives to conventional solar cells. However, long-term stability and light-to-energy conversion efficiency of the electrolyte in DSSCs are the main challenges in the commercial use of DSSCs. Current liquid electrolytes in DSSCs allow achieving high power conversion efficiency, but they still suffer from many disadvantages such as solvent leakage, corrosion and high volatility. Quasi-solid state electrolytes have therefore been developed in order to curb these problems. A novel polymer electrolyte composed of biobased polymer chitosan, poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), 1-methyl-3-propylimidazolium iodide ionic liquid and iodide/tri-iodide redox salts in various compositions is proposed in this study as a quasi-solid state electrolyte. Fourier transform infrared microscopy (FTIR) studies on the polymer electrolyte have shown interactions between the redox salt and the polymer blend. The quasi-solid state electrolyte tested in DSSCs with an optimised weight ratio of PVdF-HFP:chitosan (6:1) with ionic liquid electrolyte PMII/KI/I 2 has shown the highest power conversion efficiencies of 1.23% with ionic conductivity of 5.367×10 −4 S·cm −1 demonstrating the potential of using sustainable bio-based chitosan polymers in DSSCs applications.

Publicly Available April 10, 2017

Synergistic effects of retinoic acid and graphene oxide on the physicochemical and in-vitro properties of electrospun polyurethane scaffolds for bone tissue engineering

Mohammad Mahdi Safikhani, Ali Zamanian, Farnaz Ghorbani

Page range: 363-371

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Abstract

Tissue engineering scaffolds simulate extracellular matrixes (ECMs) to promote healing processes of damaged tissues. In this investigation, ECM were simulated by retinoic acid-loaded polyurethane-graphene oxide nanofibers to regenerate bone defects. Scanning electron microscopy (SEM) micrographs, Fourier transform infrared (FTIR) spectrum and X-ray diffraction (XRD) patterns proved the synthesis of graphene oxide (GO) nanosheets. SEM micrographs of nanofibers demonstrated through the formation of homogeneous and bead free fibrous scaffolds that the diameter of fibers were reduced by decreasing the applied voltage in an electrospinning process and the addition of GO. According to the results, the addition of GO to the polyurethane (PU) solution led to an increase in mechanical strength which is the most important parameter in the hard tissue repair. The GO-containing scaffolds showed an increased wettability, swelling, biodegradation and drug release level. Release behavior in nanocomposite scaffolds followed the swelling and biodegradation mechanisms, so osteogenic expression was possible by incorporating retinoic acid (RA) in PU-GO nanofibrous scaffolds. Biological evaluations demonstrated that composite scaffolds are biocompatible and support cellular attachment in which RA-loaded samples represented better cellular spreading. In brief, nanocomposite fibers showed desired that the physicochemical, mechanical and biological properties and synergic effects of GO and RA in osteogenic activity of MG-63 cells produced favorable constructs for hard tissue engineering applications.

Open Access March 31, 2017

Non-isothermal crystallization and thermal degradation kinetics of MXene/linear low-density polyethylene nanocomposites

Xinxin Cao, Mengqi Wu, Aiguo Zhou, You Wang, Xiaofang He, Libo Wang

Page range: 373-381

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Abstract

A novel two-dimensional material MXene was used to synthesize nanocomposites with linear low-density polyethylene (LLDPE). The influence of MXene on crystallization and thermal degradation kinetics of LLDPE was investigated. Non-isothermal crystallization kinetics was investigated by using differential scanning calorimetry (DSC). The experimental data was analyzed by Jeziorny theory and the Mo method. It is found that MXene acted as a nucleating agent during the non-isothermal crystallization process, and 2 wt% MXene incorporated in the nanocomposites could accelerate the crystallization rate. Findings from activation energy calculation for non-isothermal crystallization came to the same conclusion. Thermal gravity (TG) analysis of MXene/LLDPE nanocomposites was conducted at different heating rates, and the TG thermograms suggested the nanocomposites showed an improvement in thermal stability. Apparent activation energy ( E a ) of thermal degradation was calculated by the Kissinger method, and E a values of nanocomposites were higher than that of pure LLDPE. The existence of MXene seems to lead to better thermal stability in composites.

Open Access April 19, 2017

Extraction and characterization of chitin and chitosan: applications of chitosan nanoparticles in the adsorption of copper in an aqueous environment

Oumkelthoum Rahmani, Bachir Bouzid, Abdenacer Guibadj

Page range: 383-397

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Abstract

The main objective of the present work is to develop and characterize a new generation of adsorptive gelled porous bead supports made from nanoparticles of chitosan, bentonite and alginate. There were subsequently used in the purification of water synthetically polluted with cupric ions. The multiple experiments carried out on the adsorption of copper resulted in an equilibrium time reached after 10 min with an elimination percentage of 86%. Adsorption kinetics is better described by the expression of the second-order model whereas the adsorption isotherm is satisfactorily described by the Freundlich model. The different results showed the high affinity of the nanoparticle composite beads of chitosan/bentonite/alginate to cupric ions in an aqueous solution which is probably due to the presence of various chelating agents such as “NH, OH, COO − , and O” in their structure.

Open Access April 12, 2017

Systematic evaluation of pH and thermoresponsive poly(n-isopropylacrylamide-chitosan-fluorescein) microgel

Pedro Hernández, Armando Lucero-Acuña, Cindy Alejandra Gutiérrez-Valenzuela, Ramón Moreno, Reynaldo Esquivel

Page range: 399-408

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Abstract

The interesting properties of stimuli-responsive polymers lead to a wide range of possibilities in design and engineering of functional material for the biomedical application. A systematic approach focused on the evaluation of the physical properties of multiresponse (pH and temperature) PNIPAM was reported in this work. The effect of three different molar ratios of poly(n-isopropylacrylamide): chitosan (1:49, 1:99 and 1:198) were evaluated and labeled correspondingly as PC 1 F, PC 2 F, and PC 3 F. An increase in the lower critical solution temperature (LCST) of sample PC 1 F (34°C) was observed by differential scanning calorimetry (DSC). The presence of low molecular weight chitosan (LMWC) full-interpenetrating polymer (Full-IPN) segments in poly(n-isopropylacrylamide) was confirmed by Fourier-transform infrared spectroscopy (FT-IR). The hydrogel’s water capture was analyzed by two models of swelling, the power law model and a model that considers the relaxation of polymeric chains of the hydrogel, finding good correlations with experimental data in both cases. Sample PC 3 F resulted with higher swellability, increasing the weight of the hydrogel around seven times. Hydrogel pH-sensibility was confirmed placing the samples at different pH environments, with an apparent increase in swellability for acidic conditions, confirming the highest swellability for sample PC 3 F, due to hydrogen bonds boosted by chitosan high molar ratio. Based on these results, the hydrogel obtained has potential as a thermo-pH triggered hydrogel in drug delivery applications.

Open Access April 19, 2017

Plasticizer effect on melt blending of polylactide stereocomplex

Yottha Srithep, Dutchanee Pholharn

Page range: 409-416

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Abstract

Poly( l -lactide) (PLLA)/poly( d -lactide) (50/50) with plasticizer contents ranging from 2% to 16% w/w were prepared by melt blending using an internal mixer. Wide-angle X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry results confirmed that complete stereocomplex polylactide crystallites without any homocrystallites were produced. Compared to neat PLLA, the melting temperature of the stereocomplex polylactide and its plasticized samples was approximately 55°C higher. Higher plasticizer contents decreased glass transition temperature of the stereocomplex, which implied higher flexibility and enhanced the crystallization rate. However, the plasticizer in the stereocomplex reduced the thermal stability.

Open Access June 13, 2017

Polypropylene/basalt thick film composites: structural, mechanical and dielectric properties

Ümit Alkan, Yaşar Karabul, Ayşe Evrim Bulgurcuoğlu, Mehmet Kılıç, Zeynep Güven Özdemir, Orhan İçelli

Page range: 417-425

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Abstract

In this work, polypropylene/volcanic basalt rock (PP/VBR) thick film composites with different VBR powder mass ratio varying from 0.5 wt.% to 20.0 wt.% were prepared by using the hot press technique. The effects of VBR powder doping on mechanical, structural and dielectric properties of PP were investigated by stress-strain measurements, Fourier transform infrared analysis, thermal gravimetric analysis, scanning electron microscopy and dielectric spectroscopy methods. The highest tensile strength, percentage strain and energy at break were achieved for 0.5 wt.% VBR powder doped PP composite. According to the stress-percentage strain curves of the samples, it was observed that 0.5 wt.% VBR powder doping increases the mechanical performance of PP polymer. In addition, regardless of the doping concentration level of basalt powder, the real part of complex dielectric function ( ε ′) of all PP composites display approximately frequency independent behavior between 100 Hz and 1 MHz. On the other hand, 0.5 wt.% VBR powder doped PP composite has also the lowest dielectric constant at the vicinity of 2.7 between 100 Hz and 1 MHz. The composite also has considerably low dielectric loss which has a crucial importance for technological applications. For these reasons, PP/0.5 wt.% VBR composite with the highest tensile strength can be considered as a suitable candidate for microelectronic devices. Furthermore, the alternative current conductivity mechanism was determined as nearly constant loss due to approximately constant dielectric loss between 10 Hz and 1 MHz.

Open Access June 23, 2017

Performance properties of rigid polyurethane-polyisocyanurate/brewers’ spent grain foamed composites as function of isocyanate index

Aleksander Hejna, Józef Haponiuk, Łukasz Piszczyk, Marek Klein, Krzysztof Formela

Page range: 427-437

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Abstract

In the presented work, rigid polyurethane-polyisocyanurate (PUR-PIR) foams filled with brewers’ spent grain (BSG) were prepared. The influence of the isocyanate index (II) on its performance was investigated. Foams obtained with higher isocyanate index required a higher amount of hydrofluorocarbon physical blowing agent to provide the same apparent density of material. An increase of isocyanate index resulted in a slight decrease of cell size, which was related to the increased crosslink density due to enhanced generation of allophanate and biuret groups. Deterioration of compressive strength, from 226 to 202 kPa was observed with the rise of the isocyanate index. Dynamic mechanical analysis and swelling tests confirmed the increase of crosslink density with the increasing isocyanate index. The glass transition temperature rose from 165.7°C to 193.2°C. Fourier transform infrared (FTIR) analysis indicated an increase of the isocyanurate rings’ content in composites with a higher isocyanate index, causing noticeable enhancement of thermal stability. The onset of degradation was shifted from 196°C to 211°C.

Open Access June 17, 2017

Synthesis and characterization of polyvinylmethylsiloxanes by cationic polymerization using a solid green catalyst

Djamal Eddine Kherroub, Mohammed Belbachir, Saad Lamouri

Page range: 439-448

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Abstract

The present work is devoted to the synthesis and characterization of vinylsiloxane polymers produced by the use of an activated natural catalyst known as Maghnite-H + . The cationic ring opening polymerization of pentavinylpentamethylcyclopentasiloxane (V5D5) made it possible to obtain the desired polymeric materials. Through this study, we have adapted a new strategy of synthesis of a siloxane polymer with relatively high molecular mass, using a solid initiator activated by sulfuric acid, which has enabled us to combine the ecological aspect of synthesis and the effectiveness of the catalyst in this kind of reaction. Structural [infrared (IR), proton and carbon nuclear magnetic resonance ( 1 H NMR and 13 C NMR)], thermal differential scanning (DSC) and chromatographic (GPC) characterization methods have allowed the products obtained to be identified and their various properties to be focused on. The kinetic study was made to determine the order of the reaction. The proposed reaction mechanism shows the advantages of Maghnite-H + .

About this journal

e-Polymers is an open access, single-blind peer-reviewed scientific journal. The aim of e-Polymers is to publish, in an ongoing way, pure and applied polymer-science-related original research articles, reviews, and feature articles. It includes synthetic methodologies, characterization, and processing techniques for polymer materials. Reports on interdisciplinary polymer science and on applications of polymers in all areas are welcome.

In 2013 e-Polymers has been transferred from the e-Polymer Foundation to the scientific publisher De Gruyter. Prof. Seema Agarwal and Prof. Andreas Greiner took over as Editors-in-Chief. e-Polymers is dedicated to serve the polymer community and will continue publishing scientific contributions on highest possible standards.

The present Editor-in-Chief, Prof. Seema Agarwal, would like to thank the authors, the reviewers, the editorial staff, the advisory board, and the supporting organization that made e-Polymers a successful and sustainable scientific journal of the polymer community. The Editors of e-Polymers feel very much engaged to provide best publishing services at the highest possible level.

Topics

Pure and Applied Polymer Science
Organic Chemistry
Industrial Chemistry
Polymer Science and Technology

Article formats
Research Article, Review Article, Rapid Communication, Erratum

Information on submission process

Secure archiving by De Gruyter and the independent archiving service Portico

Special Issues:

"Biodegradable and bio-based polymers: Green approaches"
Guest Editors: Dr. Kumaran Subramanian (Sathyabama Institute of Science and Technology, Jeppiaar Nagar, India), Prof. A. Wilson Santhosh Kumar (AMITY University, Mumbai, India), and　Dr. Venkatajothi Ramarao (The Copperbelt University, Ndola, Zambia)

Submission deadline: August 31, 2023