International Journal of Polymer Science The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. The Application of Polysaccharide Biocomposites to Repair Cartilage Defects Thu, 17 Apr 2014 16:44:10 +0000 Owing to own nature of articular cartilage, it almost has no self-healing ability once damaged. Despite lots of restore technologies having been raised in the past decades, no repair technology has smoothly substituted for damaged cartilage using regenerated cartilage tissue. The approach of tissue engineering opens a door to successfully repairing articular cartilage defects. For instance, grafting of isolated chondrocytes has huge clinical potential for restoration of cartilage tissue and cure of chondral injury. In this paper, SD rats are used as subjects in the experiments, and they are classified into three groups: natural repair (group A), hyaluronic acid repair (group B), and polysaccharide biocomposites repair (hyaluronic acid hydrogel containing chondrocytes, group C). Through the observation of effects of repairing articular cartilage defects, we concluded that cartilage repair effect of polysaccharide biocomposites was the best at every time point, and then the second best was hyaluronic acid repair; both of them were better than natural repair. Polysaccharide biocomposites have good biodegradability and high histocompatibility and promote chondrocytes survival, reproduction, and spliting. Moreover, polysaccharide biocomposites could not only provide the porous network structure but also carry chondrocytes. Consequently hyaluronic acid-based polysaccharide biocomposites are considered to be an ideal biological material for repairing articular cartilage. Feng Zhao, Wei He, Yueling Yan, Hongjuan Zhang, Guoping Zhang, Dehu Tian, and Hongyang Gao Copyright © 2014 Feng Zhao et al. All rights reserved. The Experimental Study on Promoting the Ilizarov Distraction Osteogenesis by the Injection of Liquid Alg/nHAC Biocomposites Mon, 14 Apr 2014 08:18:07 +0000 Limb lengthening is frequently utilized in treating limb length inequalities, angulation deformities, nonunions, complex fractures, and deficiencies after tumor resection in more recent year. The procedure of limb lengthening pioneered by Ilizarov is now a widely accepted method for correcting limb length inequality and short stature as well as for bridging large defects in long bones. In order to promote bone healing during distraction osteogenesis and reduce the complications caused by limb lengthening pioneered, an alginate/nanohydroxyapatite/collagen (Alg/nHAC) composite was fabricated. General observation, histologically morphological observations, X-ray examination, biomechanical test, bone density, and the percentage area of bone trabecula were used to assay the ability of Alg/nHAC composite to promote bone healing. The present study demonstrates that the injection of liquid Alg/nHAC composites can significantly promote distraction osteogenesis. Alg/nHAC composite is promising for clinical application, solving the healing problem of backbone osteotomy and the fixing problem of metaphyseal backbone. Xinhui Liu, Di Yu, Jieyan Xu, Chao Zhu, Qingling Feng, Chuanyong Hou, Hua Wang, Yelin Yang, and Guoping Guan Copyright © 2014 Xinhui Liu et al. All rights reserved. Poly(Butylene Terephthalate) Based Composites Containing Alumina Whiskers: Influence of Filler Functionalization on Dielectric Properties Wed, 02 Apr 2014 06:44:58 +0000 Poly(butylene terephthalate) (PBT) is one of the most widely used semicrystalline thermoplastics polyester because of its superior thermal and mechanical properties, high dimensional stability and excellent processability. In this research PBT-based nanocomposites, including various amounts (up to 10 wt%) of commercial alumina whiskers, have been prepared by using a Brabender internal chamber mixer and analysed in terms of morphological features and dielectric properties. Specific attention has been focused on the effect of the filler functionalization considering 3-glycidoxy propylmethoxysilane (GPS) or 3-methacryloxypropyltrimethoxysilane (MPS) as coupling agents. Tests, performed on compounds filled with neat and functionalized alumina whiskers, show a clear dependence of relative dielectric permittivity , invariance of dissipation factor (), and a sensible increase of volume electrical resistivity with the filler’s content and are encouraging for a future introduction of such composites in many electrical applications. Pietro Russo, Francesca Cimino, Domenico Acierno, Giovanni Lupò, and Carlo Petrarca Copyright © 2014 Pietro Russo et al. All rights reserved. Post-Heat Treatment and Mechanical Assessment of Polyvinyl Alcohol Nanofiber Sheet Fabricated by Electrospinning Technique Tue, 01 Apr 2014 07:56:26 +0000 Polyvinyl alcohol (PVA) sheets based nanofibers were produced by electrospinning technique. Postheat treatment of the produced PVA sheets with temperatures both below and above Tg to improve the mechanical properties of this material is conducted. The morphology, microstructures, and thermal degradation of the nanofibers sheets produced were investigated using scanning electron microscopy (SEM), transmission electron microscope (TEM), and thermal gravimetric analysis (TGA). Produced nanofibers are compact, and entangled with each other, with diameters from around 150 to 210. Some mechanical characteristics of the successfully produced PVA sheets, and heat-treated, are then conducted and assessed employing uniaxial tensile tests at different speeds ranging from 1 mm/min to 100 mm/min. The tensile test results obtained show that the PVA sheets are strain rate sensitive with increasing strength as the speed (i.e., strain rate) increases. The yield tensile stress ranges from 2.411 to 6.981 MPa, the ductility (i.e., elongation percent) from ∼21 to 60%, and Young modulus ranges from 103 to 0.137 KPa. However, for heat-treated samples, it is found that the yield strength increases almost by ∼35–40% more than the values of untreated cases with values reaching up to about 3.627–9.63 MPa. Mahir Es-saheb and Ahmed Elzatahry Copyright © 2014 Mahir Es-saheb and Ahmed Elzatahry. All rights reserved. Enhancement of VEGF on Axial Vascularization of Nano-HA/Collagen/PLA Composites: A Histomorphometric Study on Rabbits Mon, 31 Mar 2014 14:31:30 +0000 The aim of this study was to investigate whether the nanohydroxyapatite/collagen/poly(L-lactic acid) (nHAC/PLA) composite is suitable to be compounded with VEGF to enhance the axial vascularization in vivo. Thirty rabbits were divided into 2 groups of 15 animals each. In control group, a nHAC/PLA scaffold slice was vascularized axially by an inserted ligated femoral arteriovenous (AV) bundle in the animal. In experimental group, a slice compounded with VEGF gel was applied. The rabbits were sacrificed at 2 weeks, 6 weeks, and 10 weeks after surgery; the specimens of scaffold slices underwent histomorphometric examination; analysis of the microvessel density (MVD) of both groups was done. The combination with VEGF (Group B) did not enhance the vascularization in early phase (2 and 6 weeks, ) but worked in later phase (10 weeks, ). The data of the experiment demonstrated the suitability of the nHAC/PLA composite as carrier for the growth factor VEGF, enabling its sustained release in bioactive form with enough binding efficacy. Xiao Chang, Hai Wang, Zhihong Wu, Xiaojie Lian, Fuzhai Cui, Xisheng Weng, Bo Yang, Guixing Qiu, and Baozhong Zhang Copyright © 2014 Xiao Chang et al. All rights reserved. An Investigation on the Properties of Palm-Based Polyurethane Solid Polymer Electrolyte Sun, 30 Mar 2014 14:18:42 +0000 Palm-based polyurethane electrolyte was prepared via prepolymerization method between palm kernel oil polyol (PKO-p) and 2,4′-diphenylmethane diisocyanate (MDI) in acetone at room temperature with the presence of lithium trifluoromethanesulfonate (LiCF3SO3). The effect of varying the concentration of LiCF3SO3 salt on the ionic conductivity, chemical interaction, and structural and morphological properties of the polyurethane solid polymer electrolyte was investigated. The produced film was analyzed using electrochemical impedance spectroscopy (EIS), attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The EIS result showed that the highest ionic conductivity was at 30 wt% LiCF3SO3 with a value of 1.6 × 10−5 Scm−1. Infrared analysis showed the interaction between lithium ions and amine group (–N–H) at (3600–3100 cm−1), carbonyl group (–C=O) at (1750–1650 cm−1), and ether group (–C–O–C–) at (1150–1000 cm−1) of the polyurethane forming polymer-salt complexes. The XRD result proved that LiCF3SO3 salt completely dissociates within the polyurethane film as no crystalline peaks of LiCF3SO3 were observed. The morphological study revealed that the films prepared have a good homogeneity and compatibility as no phase separation occurred. Farah Nadia Daud, Azizan Ahmad, and Khairiah Haji Badri Copyright © 2014 Farah Nadia Daud et al. All rights reserved. Characterization of Functionalized Polyurethane Foam for Lead Ion Removal from Water Mon, 10 Mar 2014 13:01:14 +0000 Polyurethane foams functionalized with sulfonic acid groups are used in this study to exchange lead (Pb2+) ions from aqueous solutions. Toluene-2, 4-diisocyanate, 2,6-diisocyanate (TDI) was reacted with Polypropylene glycol 1200 (PPG) in 2 : 1 molar ratio to form a linear prepolymer. The linear prepolymer was further polymerized using N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES), which acts both as a chain extender and an ion-exchanger for Pb2+ ions. The functionalized polyurethane foam was characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The Pb2+ ion exchange capacity was determined using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The maximum Pb2+ ion exchange capacity of the foam was found to be 51 ppb/g from a 100 ppb Pb2+ solution over a period of two hours. In addition, pH analysis was carried out on the foam composition with the best Pb2+ ion removal capacity. The pH results based on two-hour exposures showed that the functionalized polyurethane foam performed better at lower pH levels. Subhashini Gunashekar and Nidal Abu-Zahra Copyright © 2014 Subhashini Gunashekar and Nidal Abu-Zahra. All rights reserved. Vascularization of Nanohydroxyapatite/Collagen/Poly(L-lactic acid) Composites by Implanting Intramuscularly In Vivo Mon, 10 Mar 2014 11:46:44 +0000 It still remains a major challenge to repair large bone defects in the orthopaedic surgery. In previous studies, a nanohydroxyapatite/collagen/poly(L-lactic acid) (nHAC/PLA) composite, similar to natural bone in both composition and structure, has been prepared. It could repair small sized bone defects, but they were restricted to repair a large defect due to the lack of oxygen and nutrition supply for cell survival without vascularization. The aim of the present study was to investigate whether nHAC/PLA composites could be vascularized in vivo. Composites were implanted intramuscularly in the groins of rabbits for 2, 6, or 10 weeks (). After removing, the macroscopic results showed that there were lots of rich blood supply tissues embracing the composites, and the volumes of tissue were increasing as time goes on. In microscopic views, blood vessels and vascular sprouts could be observed, and microvessel density (MVD) of the composites trended to increase over time. It suggested that nHAC/PLA composites could be well vascularized by implanting in vivo. In the future, it would be possible to generate vascular pedicle bone substitutes with nHAC/PLA composites for grafting. Hai Wang, Xiao Chang, Guixing Qiu, Fuzhai Cui, Xisheng Weng, Baozhong Zhang, Xiaojie Lian, and Zhihong Wu Copyright © 2014 Hai Wang et al. All rights reserved. Enhancement of Fluorescent Labeling via a Composited Thin Film Mon, 03 Mar 2014 16:13:11 +0000 Fluorescent labeling is the prevailing imaging technique in cell biological research. When statistical investigations on a large number of cells are involved, experimental study is required for both low magnification to get a reliable statistical population and high contrast to achieve accurate diagnosis on the nature of the cells’ perturbation. As microscope objectives of low magnification generally yield low collection efficiency, such studies are limited by the fluorescence signal weakness. To overcome this technological insufficiency, Le Moal et al. proposed a method based on metal-coated substrates that enhanced the fluorescence process and improved collection efficiency in fluorescence microscope observation and that could be directly used with a common microscope setup. In this paper, we use an Ag-Si3N4-Ag multilayer film coated on the substrate and numerically analyse the optical behavior of a fluorophore which was placed above the composited film coated on the substrate. The results shows that by using an Ag-Si3N4-Ag composited film the fluorescence imaging can be enhanced remarkably. Taikei Suyama, Xiaowei Ji, and Yaoju Zhang Copyright © 2014 Taikei Suyama et al. All rights reserved. Effect of Nano ZnO on the Optical Properties of Poly(vinyl chloride) Films Sun, 02 Mar 2014 14:16:28 +0000 Optical properties of pure and doped poly(vinyl chloride) (PVC) films, prepared by using casting technique, with different nanosize zinc oxide (ZnO) concentrations (1–20) wt% have been studied. Parameters such as extinction coefficient, refractive index, real and imaginary parts, Urbach energy, optical conductivity, infinitely high frequency dielectric constant, and average refractive index were studied by using the absorbance and transmittance measurement from computerized UV-visible spectrophotometer (Shimadzu UV-1601 PC) in the spectral range 200–800 nm. This study reveals that the optical properties of PVC are affected by the doping of ZnO where the absorption increases and transmission decreases as ZnO concentration increases. The extinction coefficient, refractive index, real and imaginary parts, infinitely high frequency dielectric constant, and average refractive index values were found to increase with increasing impurity percentage. The Urbach energy values are found to be decreasing with increasing ZnO concentration. The optical conductivity increased with photon energy after being doped and with the increase of ZnO concentration. Wasan Al-Taa’y, Mohammed Abdul Nabi, Rahimi M. Yusop, Emad Yousif, Bashar Mudhaffar Abdullah, Jumat Salimon, Nadia Salih, and Saiful Irwan Zubairi Copyright © 2014 Wasan Al-Taa’y et al. All rights reserved. Properties of RF-Sputtered PZT Thin Films with Ti/Pt Electrodes Thu, 27 Feb 2014 11:29:09 +0000 Effect of annealing temperature and thin film thickness on properties of Pb(Zr0.53Ti0.47)O3 (PZT) thin film deposited via radiofrequency magnetron sputtering technique onto Pt/Ti/SiO2/Si substrate was investigated. Average grain sizes of the PZT thin film were measured by atomic force microscope; their preferred orientation was studied through X-ray diffraction analysis. Average residual stress in the thin film was estimated according to the optimized Stoney formula, and impedance spectroscopy characterization was performed via an intelligent LCR measuring instrument. Average grain sizes of PZT thin films were 60 nm~90 nm and their average roughness was less than 2 nm. According to X-ray diffraction analysis, 600°C is the optimal annealing temperature to obtain the PZT thin film with better crystallization. Average residual stress showed that thermal mismatch was the decisive factor of residual stress in Pt/Ti/SiO2/Si substrate; the residual stress in PZT thin film decreased as their thickness increased and increased with annealing temperature. The dielectric constant and loss angle tangent were extremely increased with the thickness of PZT thin films. The capacitance of the device can be adjusted according to the thickness of PZT thin films. Cui Yan, Yao Minglei, Zhang Qunying, Chen Xiaolong, Chu Jinkui, and Guan Le Copyright © 2014 Cui Yan et al. All rights reserved. Lactic Acid Yield Using Different Bacterial Strains, Its Purification, and Polymerization through Ring-Opening Reactions Mon, 17 Feb 2014 12:13:05 +0000 Laboratory-scale anaerobic fermentation was performed to obtain lactic acid from lactose, using five lactic acid bacteria: Lactococcus lactis, Lactobacillus bulgaricus, L. delbrueckii, L. plantarum, and L. delbrueckii lactis. A yield of 0.99 g lactic acid/g lactose was obtained with L. delbrueckii, from which a final concentration of 80.95 g/L aqueous solution was obtained through microfiltration, nanofiltration, and inverse osmosis membranes. The lactic acid was polymerized by means of ring-opening reactions (ROP) to obtain poly-DL-lactic acid (PDLLA), with a viscosity average molecular weight (Mv) of 19,264 g/mol. F. G. Orozco, A. Valadez-González, J. A. Domínguez-Maldonado, F. Zuluaga, L. E. Figueroa-Oyosa, and L. M. Alzate-Gaviria Copyright © 2014 F. G. Orozco et al. All rights reserved. Correlation of Polymerization Conditions with Thermal and Mechanical Properties of Polyethylenes Made with Ziegler-Natta Catalysts Tue, 11 Feb 2014 11:31:33 +0000 In this study, the synthesis of polyethylenes has been carried out with titanium-magnesium supported Ziegler-Natta catalysts in laboratory-scale reactors. A correlation of different polymerization conditions with thermal and mechanical properties of polyethylenes has been established. It is seen that there is lowering of molecular weight (Mw), polymer yield, and catalyst activity at high hydrogen pressure and high temperature. The Mw, polymer yield, and catalyst activity are improved with the increase in ethylene pressure. Dynamic mechanical analysis (DMA) results show that the increase in temperature and hydrogen pressure decreases storage modulus. The samples with higher Mw showed high activation energy. The melting point decreases with the increase in hydrogen pressure but increases slightly with the increase in ethylene pressure. It is seen that the increase in reaction temperature, ethylene pressure, and hydrogen pressure leads to an increase in crystallinity. The tensile modulus increases with the increase in hydrogen pressure and can be correlated with the crystallinity of polymer. The Mw has a major influence on the flow activation energy and tensile strength. But the other mechanical and thermal properties depend on Mw as well as other parameters. M. Anwar Parvez, Mostafizur Rahaman, M. A. Suleiman, J. B. P. Soares, and I. A. Hussein Copyright © 2014 M. Anwar Parvez et al. All rights reserved. Towards a Smart Encapsulation System for Small-Sized Electronic Devices: A New Approach Sun, 09 Feb 2014 09:59:10 +0000 Miniaturized analytical chip devices like biosensors nowadays provide assistance in highly diverse fields of application such as point-of-care diagnostics and industrial bioprocess engineering. However, upon contact with fluids, the sensor requires a protective shell for its electrical components that simultaneously offers controlled access for the target analytes to the measuring units. We therefore developed a capsule that comprises a permeable and a sealed compartment consisting of variable polymers such as biocompatible and biodegradable polylactic acid (PLA) for medical applications or more economical polyvinyl chloride (PVC) and polystyrene (PS) polymers for bioengineering applications. Production of the sealed capsule compartments was performed by heat pressing of polymer pellets placed in individually designable molds. Controlled permeability of the opposite compartments was achieved by inclusion of NaCl inside the polymer matrix during heat pressing, followed by its subsequent release in aqueous solution. Correlating diffusion rates through the so made permeable capsule compartments were quantified for preselected model analytes: glucose, peroxidase, and polystyrene beads of three different diameters (1.4 μm, 4.2 μm, and 20.0 μm). In summary, the presented capsule system turned out to provide sufficient shelter for small-sized electronic devices and gives insight into its potential permeability for defined substances of analytical interest. Sebastian-Tim Schmitz-Hertzberg, Rick Liese, Carsten Terjung, and Frank F. Bier Copyright © 2014 Sebastian-Tim Schmitz-Hertzberg et al. All rights reserved. Evaluation of Some Conducting Polymers as Novel Antioxidants for Rubber Vulcanizates Sun, 09 Feb 2014 06:58:49 +0000 Natural rubber (NR) and styrene-butadiene rubber (SBR) formulations containing polyaromatic and polyheterocyclic amine homopolymers and copolymers were prepared. The studied homopolymers named polythiophene (PT), poly(o-phenylene diamine) (Po-PDA) and copolymers named poly(aniline-co-m-toluidine) (PAn-co-mT), poly(aniline-co-o-phenylene diamine) (PAn-co-o-PDA), poly(aniline-co-thiophene) (PAn-co-T), poly(aniline-co-2-amino pyridine) (PAn-co-2APy), and poly(2-amino pyridine-co-o-phenylene diamine) (P2APy-co-o-PDA) have been prepared and characterized. The rheological characteristics and physicomechanical properties of the compounded rubber mixes and vulcanizates were investigated and determined. The effects of the prepared polymers on the ageing characteristics of corresponding vulcanizates were evaluated. It was found that the prepared polymers have shown better antioxidant efficiency than the conventional antioxidants phenyl β naphthyl amine (PβN) and the polymerized-2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) industrially used in addition to their safety and ecofriendliness to the environment. M. A. Abd El-Ghaffar, K. A. Shaffei, and Nourelhoda Abdelwahab Copyright © 2014 M. A. Abd El-Ghaffar et al. All rights reserved. Copolymerization of 4-Acetylphenyl Methacrylate with Ethyl Methacrylate: Synthesis, Characterization, Monomer Reactivity Ratios, and Thermal Properties Tue, 04 Feb 2014 09:48:14 +0000 Methacrylates have high glass transition temperature () values and high thermal stability. A new methacrylate copolymer, poly(4-acetylphenyl methacrylate-co-ethyl methacrylate) (APMA-co-EMA), was synthesized. The thermal behaviors of copolymers were investigated by differential scanning calorimetry and thermogravimetric analysis. They behaved as new single polymers with single ’s and the thermal stability of the copolymers increased with increasing 4-acetylphenyl methacrylate (APMA) fraction, leading to the manufacture of copolymers with desired values. Structure and composition of copolymers for a wide range of monomer feed ratios were determined by Fourier transform infrared (FT-IR) and 1H-nuclear magnetic resonance (1H-NMR) spectroscopic techniques. Copolymerization reactions were continued up to 40% conversions. The monomer reactivity ratios for copolymer system were determined by the Kelen-Tüdös (; ) and extended Kelen-Tüdös (; ) methods and a nonlinear least squares (; ) method. Gamze Barim and Mustafa Gokhun Yayla Copyright © 2014 Gamze Barim and Mustafa Gokhun Yayla. All rights reserved. Preparation and Characterization of Starch Nanoparticles for Controlled Release of Curcumin Wed, 29 Jan 2014 00:00:00 +0000 Curcumin was loaded onto starch nanoparticles by using in situ nanoprecipitation method and water-in-oil microemulsion system. Curcumin loaded starch nanoparticles exhibited enhanced solubility in aqueous solution as compared to free curcumin. Effects of formulation parameters such as types of reaction medium, types of surfactant, surfactant concentrations, oil/ethanol ratios, loading time, and initial curcumin concentration were found to affect the particle size and loading efficiency (LF) of the curcumin loaded starch nanoparticles. Under optimum conditions, curcumin loaded starch nanoparticles with mean particles size of 87 nm and maximum loading efficiency of 78% were achieved. Curcumin was observed to release out from starch nanoparticles in a sustained way under physiological pH over a period of 10 days. Suk Fun Chin, Siti Nur Akmar Mohd Yazid, and Suh Cem Pang Copyright © 2014 Suk Fun Chin et al. All rights reserved. Properties of Edible Films Based on Oxidized Starch and Zein Thu, 09 Jan 2014 13:05:18 +0000 The objective of this work was to investigate the effect of zein and film formulation on mechanical and structural properties of native (FNS), and oxidized with 2.5% (FOSA) and 3.5% (FOSB) banana starch. The oxidized starch showed differences from native starch due to the oxidation process, showing a decrease in lipids, proteins, and amylose. The increase of the sodium hypochlorite increased the content of carbonyl and carboxyl groups in the ranges 0.015–0.028% and 0.022–0.031%, respectively. The film obtained from FOSB displayed the highest tensile strength (5.05 MPa) and satisfactory elongation value (27.1%). The zein addition caused a decrease in these mechanical properties, as well as a significant decrease in water vapour permeability (WVP). However, films from FOSA and FOSB showed higher permeability than that of the native starch. The addition of glycerol and the level of oxidation increased the films moisture. Micrographs showed that, during the oxidation process, impurities were largely eliminated from the starch granule, noting more homogeneous structures both in granules and films. Elizabeth Argüello-García, Javier Solorza-Feria, J. Rodolfo Rendón-Villalobos, Francisco Rodríguez-González, Alfredo Jiménez-Pérez, and Emmanuel Flores-Huicochea Copyright © 2014 Elizabeth Argüello-García et al. All rights reserved. Polystyrene Microbeads by Dispersion Polymerization: Effect of Solvent on Particle Morphology Thu, 09 Jan 2014 07:35:44 +0000 Polystyrene microspheres (PS) were synthesized by dispersion polymerization in ethanol/2-Methoxyethanol (EtOH/EGME) blend solvent using styrene (St) as monomer, azobisisobutyronitrile (AIBN) as initiator, and PVP (polyvinylpyrrolidone) K-30 as stabilizer. The typical recipe of dispersion polymerization is as follows: St/Solvent/AIBN/PVP = 10 g/88 g/0.1 g/2 g. The morphology of polystyrene microspheres was characterized by the scanning electron microscopy (SEM) and the molecular weights of PS particles were measured by the Ubbelohde viscometer method. The effect of ethanol content in the blend solvent on the morphology and molecular weight of polystyrene was studied. We found that the size of polystyrene microspheres increased and the molecular weight of polystyrene microspheres decreased with the decreasing of the ethanol content in the blend solvent from 100 wt% to 0 wt%. What is more, the size monodispersity of polystyrene microspheres was quite good when the pure ethanol or pure 2-Methoxyethanol was used; however when the blend ethanol/2-Methoxyethanol solvent was used, the polystyrene microspheres became polydisperse. We further found that the monodispersity of polystyrene microspheres can be significantly improved by adding a small amount of water into the blend solvent; the particles became monodisperse when the content of water in the blend solvent was up to 2 wt%. Lei Jinhua and Zhou Guangyuan Copyright © 2014 Lei Jinhua and Zhou Guangyuan. All rights reserved. Ingredient of Biomass Packaging Material and Compare Study on Cushion Properties Mon, 06 Jan 2014 08:10:57 +0000 In order to reduce the white pollution caused by nondegradable waste plastic packaging materials, the biomass cushion packaging material with straw fiber and starch as the main raw materials had been synthesized. The orthogonal experiment was used to study the impact of mass ratio of fiber to starch, content of plasticizer, active agent, and foaming agent on the compressive strength of cushion material. Infrared spectrometer and theory of water’s bridge-connection were used to study the hydroxyl groups among the fiber and starch. The results were demonstrated as follows: the mass ratio of fiber to starch had the most significant impact on compressive strength. When the contents of the plasticizer, the foaming agent, and the active agent were, respectively, 12%, 0.1%, and 0.3% and the mass ratio of fiber to starch was 2 : 5, the compressive strength was the best up to 0.94 MPa. Meanwhile, with the plasticizer content and the mass ratio of fiber to starch increasing, the cushioning coefficient of the material decreased first and then increased. Comparing the cushion and rebound performance of this material with others, the biomass cushion packaging material could be an ideal substitute of plastic packaging materials such as EPS and EPE. Fangyi Li, Kaikai Guan, Peng Liu, Gang Li, and Jianfeng Li Copyright © 2014 Fangyi Li et al. All rights reserved. Permeability of Porous Poly(3-hydroxybutyrate) Barriers of Single and Bilayer Type for Implant Applications Thu, 02 Jan 2014 14:13:06 +0000 Poly(3-hydroxybutyrate) (PHB) is a polyester which shows excellent biocompatibility and a PHB material is therefore considered suitable for many biomedical applications. A highly porous PHB material may be designed to facilitate the transport of small molecules and body fluids or serve as a biocompatible temporary barrier. In this study, PHB films with varying degree of porosity and pore interconnectivity were made by solvent casting using water-in-oil emulsion templates of varying composition. The morphology was characterized by SEM and the water permeability of the films was determined. The results show that an increased water content of the template emulsion resulted in a film with increased porosity. A fine tuning of the film morphology of the casted films was achieved by varying the salt content of the water phase of the template emulsion. The porosity of these films was roughly the same but the water permeability varied between and . It was concluded that the major determinant of the water permeability through these films is the pore interconnectivity. Furthermore, we report on the formation and water permeability of bilayer PHB films consisting of a porous layer combined with a dense backing layer. Anna Bergstrand, Sanna Uppström, and Anette Larsson Copyright © 2014 Anna Bergstrand et al. All rights reserved. Potential of Cellulose-Based Superabsorbent Hydrogels as Water Reservoir in Agriculture Tue, 31 Dec 2013 14:29:49 +0000 The present work deals with the development of a biodegradable superabsorbent hydrogel, based on cellulose derivatives, for the optimization of water resources in agriculture, horticulture and, more in general, for instilling a wiser and savvier approach to water consumption. The sorption capability of the proposed hydrogel was firstly assessed, with specific regard to two variables that might play a key role in the soil environment, that is, ionic strength and pH. Moreover, a preliminary evaluation of the hydrogel potential as water reservoir in agriculture was performed by using the hydrogel in experimental greenhouses, for the cultivation of tomatoes. The soil-water retention curve, in the presence of different hydrogel amounts, was also analysed. The preliminary results showed that the material allowed an efficient storage and sustained release of water to the soil and the plant roots. Although further investigations should be performed to completely characterize the interaction between the hydrogel and the soil, such findings suggest that the envisaged use of the hydrogel on a large scale might have a revolutionary impact on the optimization of water resources management in agriculture. C. Demitri, F. Scalera, M. Madaghiele, A. Sannino, and A. Maffezzoli Copyright © 2013 C. Demitri et al. All rights reserved. A Novel Continuous Extrusion Process to Fabricate Wedge-Shaped Light Guide Plates Thu, 12 Dec 2013 13:59:47 +0000 Backlight modules are key components in thin-film transistor liquid crystal displays (TFT-LCD). Among the components of a backlight module, the light guide plate (LGP) plays the most important role controlling the light projected to the eyes of users. A wedge-shaped LGP, with its asymmetrical structure, is usually fabricated by an injection proces, but the fabrication time of this process is long. This study proposes a continuous extrusion process to fabricate wedge-shaped LGPs. This continuous process has advantages for mass production. Besides a T-die and rollers, this system also has an in situ monitor of the melt-bank that forms during the extrusion process, helping control the plate thickness. Results show that the melt bank has a close relationship with the plate thickness. The temperature of the bottom heater and roller was adjusted to reduce the surface deformation of the wedge-shaped plate. This continuous extrusion system can successfully manufacture wedge-shaped LGPs for mass production. Wen-Tse Hsiao, Jui-Chang Lin, Keng-Shiang Huang, Chih-Hui Yang, Alexandru Mihai Grumezescu, Shih-Feng Tseng, and Yung-Sheng Lin Copyright © 2013 Wen-Tse Hsiao et al. All rights reserved. Novel Composite Materials for Chiral Separation from Cellulose and Barium Sulfate Wed, 11 Dec 2013 09:05:34 +0000 Cellulose was dissolved in an aqueous solution of sodium hydroxide (NaOH) and urea followed by the addition of barium sulfate (BaSO4) to yield the BaSO4/cellulose composite particles. The morphology, particle size, and BaSO4 content of the composite particles were adjusted by controlling the feed ratio of cellulose and BaSO4. The cellulose within the composite particles then reacted with 3,5-dimethylphenyl isocyanate. The resulting materials were utilized as the chiral stationary phases (CSPs) whose enantioseparation capabilities were evaluated by various chiral analytes. Due to the mechanical enhancement effect of BaSO4, the composite particles could be applied to the chromatographic packing materials. Wei Chen, Zhaoqun Wang, Xiaolin Xie, Xingping Zhou, and Zheng-Wu Bai Copyright © 2013 Wei Chen et al. All rights reserved. The Effect of H-Bonding on Radical Copolymerization of Maleic Anhydride with N-tert-Butylacrylamide and Its Characterization Tue, 10 Dec 2013 12:57:16 +0000 The copolymerization reaction between N-tert-butylacrylamide (NTBA) and maleic anhydride (MA) in p-dioxane solution at 65°C using 2,2′-azoisobutyronitrile (AIBN) as an initiator in nitrogen atmosphere was carried out. The chemical structure of the obtained copolymers from a wide range of monomer feeds was determined by elemental analysis (content of N for NTBA units), Fourier transform infrared (FTIR), and 1H-NMR spectroscopy. Also, the amounts of MA units in the copolymers were found using the chemical titration method. An observed tendency toward alternating copolymerization at ≤50 mol% NTBA concentration in monomer feed and relatively high activity of NTBA growing radical was explained by H-bond formation between C=O (anhydride) and NH (amide) fragments during chain growth reactions. Intrinsic viscosity and the molecular weights of the synthesized copolymers depend on the type of comonomer and the amount of NTBA units in the copolymers. The synthesized poly(NTBA-MA)s containing a functional amphiphilic group show both temperature and pH sensitivity and can be used for biological proposes as a physiologically active macromolecular system. Ahmet Okudan and Ayşe Karasakal Copyright © 2013 Ahmet Okudan and Ayşe Karasakal. All rights reserved. Improved Performance of an Epoxy Matrix as a Result of Combining Graphene Oxide and Reduced Graphene Mon, 09 Dec 2013 08:59:26 +0000 We present an easy and effective way to improve the mechanical properties of an epoxy matrix by reinforcing it with a combination of graphene oxide (GO) and reduced graphene oxide (RGO). These nanocomposites were prepared with different load of nanofillers: 0.1, 0.4, 0.7, 1.0 wt% and a neat epoxy. Ratios of graphene oxide and reduced graphene (GO : RGO) employed were: 0 : 1, 0.25 : 0.75, 0.5 : 0.5, 0.75 : 0.25, and 1 : 0. Results show that with only 0.4 wt% and a ratio 0.2 : 0.75 of GO : RGO, tensile strength and tensile toughness are 52% and 152% higher than neat epoxy while modulus of elasticity was improved %. The obtained results suggest that it is possible achieve advantageous properties by combining graphene in oxidized and reduced conditions as it shows a synergic effect by the presence of both nanofillers. L. Ramos-Galicia, L. N. Mendez, Ana Laura Martínez-Hernández, A. Espindola-Gonzalez, I. R. Galindo-Esquivel, R. Fuentes-Ramirez, and C. Velasco-Santos Copyright © 2013 L. Ramos-Galicia et al. All rights reserved. Application of Box-Behnken Design in Optimization of Glucose Production from Oil Palm Empty Fruit Bunch Cellulose Tue, 03 Dec 2013 10:15:47 +0000 Oil palm empty fruit bunch fiber (OPEFB) is a lignocellulosic waste from palm oil mills. It contains mainly cellulose from which glucose can be derived to serve as raw materials for valuable chemicals such as succinic acid. A three-level Box-Behnken design combined with the canonical and ridge analysis was employed to optimize the process parameters for glucose production from OPEFB cellulose using enzymatic hydrolysis. Organosolv pretreatment was used to extract cellulose from OPEFB using ethanol and water as the solvents. The extracted cellulose was characterized by thermogravimetric analysis, FTIR spectroscopy, and field emission scanning electron microscopy. Hydrolysis parameters including amount of enzyme, amount of cellulose, and reaction time were investigated. The experimental results were fitted with a second-order polynomial equation by a multiple regression analysis and found that more than 97% of the variations could be predicted by the models. Using the ridge analysis, the optimal conditions reaction time found for the production of glucose was 76 hours and 30 min, whereas the optimum amount of enzyme and cellulose was 0.5 mL and 0.9 g, respectively. Under these optimal conditions, the corresponding response value predicted for glucose concentration was 169.34 g/L, which was confirmed by validation experiments. Satriani Aga Pasma, Rusli Daik, Mohamad Yusof Maskat, and Osman Hassan Copyright © 2013 Satriani Aga Pasma et al. All rights reserved. Overmodulation Control in the Optimization of a H-PDLC Device with Ethyl Eosin as Dye Mon, 02 Dec 2013 17:53:38 +0000 The response of a H-PDLC device is improved by means of a two-step method. First, component optimization—initiator system, crosslinker, and cosolvent—enables the diffraction efficiency of the hologram to be maximized. Second, the use of N-methyl-2-pyrrolidone in combination with N-vinyl-2-pyrrolidone prevents the overmodulation in photopolymers containing ethyl eosin. Manuel Ortuño, Marina Riquelme, Sergi Gallego, Andrés Márquez, Inmaculada Pascual, and Augusto Beléndez Copyright © 2013 Manuel Ortuño et al. All rights reserved. Oil Palm Mesocarp Fiber as New Lignocellulosic Material for Fabrication of Polymer/Fiber Biocomposites Sun, 01 Dec 2013 09:33:57 +0000 New biocomposites consisting of poly (butylene succinate) (PBS) and various content (0–70 wt%) of oil palm mesocarp fiber (OPMF) or oil palm empty fruit bunch fiber (OPEFBF) were fabricated by melt blending and subsequently hotpress moulding. The tensile, flexural, and impact properties of those biocomposites were evaluated and compared. Enhancement of flexural modulus of 200 or 150% was observed with PBS biocomposite loaded with 70 wt% of OPMF or OPEFBF. PBS/OPMF biocomposites exhibited higher values of tensile, flexural and impact strengths, and tensile and flexural moduli than those of PBS/OPEFBF biocomposites. These results indicated that OPMF feature better reinforcing agent for PBS as compared to that of OPEFBF. Yoon Yee Then, Nor Azowa Ibrahim, Norhazlin Zainuddin, Hidayah Ariffin, and Wan Md Zin Wan Yunus Copyright © 2013 Yoon Yee Then et al. All rights reserved. Preparation of Conductive PANI/PVA Composites via an Emulsion Route Mon, 25 Nov 2013 17:59:21 +0000 A facile and novel strategy for preparing polyaniline/polyvinyl alcohol (PANI/PVA) composite emulsion is reported wherein the reaction is carried out via the emulsion polymerization using ammonium peroxydisulfate (APS) as the oxidizing agent and dodecylbenzene sulfonic acid (DBSA) as the protonic acid. The PANI/PVA composite membranes have been characterized using optical microscope, scanning electron microscope (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and electrochemical workstation. It is interesting that the electrical conductivity of the PANI/PVA composites is estimated to be as high as 1.28 S/cm. The experimental results show that the surface of PANI/PVA composite membranes exhibits good integrity. The PANI particles at the nanoscale are dispersed in the PVA matrix, and the electrochromic behaviors of PANI/PVA composites obtained at different polymerization temperatures can be compared based on cyclic voltammetry (CV) curves, revealing that PANI/PVA composites synthesized at room temperature are better than those synthesized at low temperature. Xiang-Qin Wang, Bin-Jie Xin, and Jian Xu Copyright © 2013 Xiang-Qin Wang et al. All rights reserved.