International Journal of Polymer Science The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Polymeric Gas-Separation Membranes for Petroleum Refining Sun, 19 Feb 2017 00:00:00 +0000 Polymeric gas-separation membranes were commercialized 30 years ago. The interest on these systems is increasing because of the simplicity of concept and low-energy consumption. In the refinery, gas separation is needed in many processes such as natural gas treatment, carbon dioxide capture, hydrogen purification, and hydrocarbons separations. In these processes, the membranes have proven to be a potential candidate to replace the current conventional methods of amine scrubbing, pressure swing adsorption, and cryogenic distillation. In this paper, applications of polymeric membranes in the refinery are discussed by reviewing current materials and commercialized units. Economical evaluation of these membranes in comparison to traditional processes is also indicated. Yousef Alqaheem, Abdulaziz Alomair, Mari Vinoba, and Andrés Pérez Copyright © 2017 Yousef Alqaheem et al. All rights reserved. Effect of Film-Forming Polymers on Release of Naftifine Hydrochloride from Nail Lacquers Thu, 16 Feb 2017 09:52:54 +0000 The successful topical therapy of onychomycosis depends on effective drug release and penetration into nail, which can be achieved by using an adequately developed delivery system. This study evaluated and compared effect of film-forming polymers Eudragit RL100, Eudragit RS100, and ethyl cellulose on naftifine hydrochloride release from experimental nail lacquer formulations. Quality of formulations was evaluated by determining drying time and water resistance. Interactions between active pharmaceutical ingredient and excipients were investigated using microcalorimetry and FT-IR. Optimization of nail lacquer formulations was performed by naftifine hydrochloride release testing. Release of naftifine hydrochloride increased with increasing concentration of Eudragit RL100. Plasticizer triacetin affected the release of naftifine hydrochloride, when Eudragit RS100 polymer was used. Ethyl cellulose polymer was determined to be not applicable for naftifine hydrochloride nail lacquer formulations. Two compositions of nail lacquers were optimized and could be used in further development of transungual delivery systems. Indrė Šveikauskaitė and Vitalis Briedis Copyright © 2017 Indrė Šveikauskaitė and Vitalis Briedis. All rights reserved. (1→3)-α-d-Glucan from Fruiting Body and Mycelium of Cerrena unicolor (Bull.) Murrill: Structural Characterization and Use as a Novel Inducer of Mutanase Thu, 16 Feb 2017 00:00:00 +0000 Water-insoluble, alkali-soluble polysaccharide (marked as ASP) was extracted from the vegetative mycelium and fruiting body of Cerrena unicolor strain. Monosaccharide examination of ASP demonstrated that the isolated biopolymer was composed mainly of glucose, xylose, and mannose monomers. The methylation investigation of studied polymers indicated that (1→3)-linked -D-Glcp is the major chain constituent (92.2% for glucans isolated from fruiting body and 90.1% from mycelium). 1H NMR, FT-IR, and immunofluorescent labelling determinations confirmed that the polysaccharides isolated from both fruiting body and mycelium of . unicolor are (1→3)--D-glucans. The obtained (1→3)--D-glucans showed differences in viscosity and similar characteristics in optical rotations. (1→3)--D-Glucans extracted from mycelium and fruiting body of C. unicolor were also used as potential and specific inducers of mutanase synthesis by Trichoderma harzianum. The highest mutanase activity (0.38 U/mL) was obtained after induction of enzyme by (1→3)--D-glucan isolated from the mycelium of C. unicolor, and this biopolymer has been suggested as a new alternative to streptococcal mutan for the mutanase induction in T. harzianum. (1→3)--D-Glucan-induced mutanase showed high hydrolysis potential in reaction with dextranase-pretreated mutan, where maximal degree of saccharification and solubilization of this bacterial homoglucan (83.1% and 78.4%, resp.) was reached in 3 h at 45°C. Monika Osińska-Jaroszuk, Adrian Wiater, Adam Choma, Małgorzata Pleszczyńska, Magdalena Jaszek, Grzegorz Janusz, Marcin Skowronek, and Janusz Szczodrak Copyright © 2017 Monika Osińska-Jaroszuk et al. All rights reserved. Study on Axial Compressive Capacity of FRP-Confined Concrete-Filled Steel Tubes and Its Comparisons with Other Composite Structural Systems Thu, 16 Feb 2017 00:00:00 +0000 Concrete-filled steel tubular (CFST) columns have been widely used for constructions in recent decades because of their high axial strength. In CFSTs, however, steel tubes are susceptible to degradation due to corrosion, which results in the decrease of axial strength of CFSTs. To further improve the axial strength of CFST columns, carbon fiber reinforced polymer (CFRP) sheets and basalt fiber reinforced polymer (BFRP) sheets are applied to warp the CFSTs. This paper presents an experimental study on the axial compressive capacity of CFRP-confined CFSTs and BFRP-confined CFSTs, which verified the analytical model with considering the effect of concrete self-stressing. CFSTs wrapped with FRP exhibited a higher ductile behavior. Wrapping with CFRP and BFRP improves the axial compressive capacity of CFSTs by 61.4% and 17.7%, respectively. Compared with the previous composite structural systems of concrete-filled FRP tubes (CFFTs) and double-skin tubular columns (DSTCs), FRP-confined CFSTs were convenient in reinforcing existing structures because of softness of the FRP sheets. Moreover, axial compressive capacity of CFSTs wrapped with CFRP sheets was higher than CFFTs and DSTCs, while the compressive strength of DSTCs was higher than the retrofitted CFSTs. Jun Deng, Yifeng Zheng, Yi Wang, Tonghua Liu, and Hui Li Copyright © 2017 Jun Deng et al. All rights reserved. Bioinspired Polyethersulfone Membrane Design via Blending with Functional Polyurethane Mon, 13 Feb 2017 00:00:00 +0000 Polyurethanes (PUs) are currently considered to be biocompatible materials but limited by a low resistance to thrombus. We therefore design a heparin-like PU (HLPU) to modify polyethersulfone (PES) membranes approaching integrated antifouling and antithrombotic properties by bioinspiration of heparin structure. Poly(vinyl pyrrolidone)-HLPU (PVP-HLPU) was synthesized via reversible addition-fragmentation chain transfer polymerization of VP using PU as a macroinitiator and then sulfonated by concentrated H2SO4. FTIR and NMR results demonstrated the successful synthesis of PVP-HLPU. By incorporation of PVP-HLPU, the cross-sectional structure of PES composite membranes altered from finger-like structure to sponge-like structure resulting in tunable permeability. The increased hydrophilicity verified by water contact angles benefited both the permeability and antifouling property. As a consequence, the composite membranes showed good blood compatibility, including decreased protein adsorption, suppressed platelet adhesion, lowered thrombin-antithrombin III generation, reduced complement activation, and prolonged clotting times. Interestingly, the PVP-capped HLPU showed better blood compatibility compared to polyethyleneglycol-capped and citric acid-capped HLPUs. The results demonstrated the enhanced antifouling and antithrombotic properties of PES hemodialysis membranes by the introduction of functional HLPUs. Also, the proposed method may forward the fabrication of hemocompatible membranes via bioinspired surface design. Mei Han, Qiang Liu, Baihai Su, Shudong Sun, and Changsheng Zhao Copyright © 2017 Mei Han et al. All rights reserved. Preparation and Properties of Composite PAN/PANI Membranes Wed, 08 Feb 2017 00:00:00 +0000 The methods of modifying PAN membranes have been known and used for many years. An interesting solution seems to be to give the sensory properties to this type of membranes. This paper presents the results of research on the method of obtaining PAN/PANI membranes using phase inversion method from a solution in DMF, following two methods: () dissolving both polymers (PAN and PANI) and then coagulating in water or in an aqueous solution of CSA and () forming the membranes from polyacrylonitrile solution and coagulation in water, followed by coating of CSA with a solution of TFE. The membranes obtained as a result of the experiment were tested for physical and chemical properties, transport properties, surface morphology, degree of dispersion of composite components, and sensitivity to the presence of dilute acids and bases. FTIR microspectroscopy and scanning electron microscopy were used to study the surface morphology. The sensory properties of membranes that are inherently colored were determined visually and by UV-Vis spectrophotometry. Furthermore, when choosing the method of membrane forming, we can obtain membranes with good physical and chemical and transport properties or ones characterized by high sensitivity to the pH of the solution. Beata Fryczkowska, Zofia Piprek, Marta Sieradzka, Ryszard Fryczkowski, and Jarosław Janicki Copyright © 2017 Beata Fryczkowska et al. All rights reserved. Influence of Hydrophilic Polymers on the Factor in Weibull Equation Applied to the Release Kinetics of a Biologically Active Complex of Aesculus hippocastanum Sun, 29 Jan 2017 12:44:45 +0000 Triterpenoid saponins complex of biological origin, escin, exhibits significant clinical activity in chronic venous insufficiency, skin inflammation, epidermal abrasions, allergic dermatitis, and acute impact injuries, especially in topical application. The aim of the study is the comparison of various hydrogel formulations, as carriers for a horse chestnut seed extract (EH). Methylcellulose (MC), two polyacrylic acid derivatives (PA1 and PA2), and polyacrylate crosspolymer 11 (PC-11) were employed. The release rates of EH were examined and a comparison with the Weibull model equation was performed. Application of MC as the carrier in the hydrogel preparation resulted in fast release rate of EH, whereas in the case of the hydrogel composed with PC-11 the release was rather prolonged. Applied Weibull function adhered best to the experimental data. Due to the evaluated shape parameter β, in the Weibull equation, the systems under study released the active compound according to the Fickian diffusion. Justyna Kobryń, Sandra Sowa, Monika Gasztych, Andrzej Dryś, and Witold Musiał Copyright © 2017 Justyna Kobryń et al. All rights reserved. Preparation of High Modulus Poly(Ethylene Terephthalate): Influence of Molecular Weight, Extrusion, and Drawing Parameters Thu, 26 Jan 2017 00:00:00 +0000 Poly(ethylene terephthalate) (PET) which is one of the most commercially important polymers, has for many years been an interesting candidate for the production of high performance fibres and tapes. In current study, we focus on investigating the effects of the various processing variables on the mechanical properties of PET produced by a distinctive process of melt spinning and uniaxial two-stage solid-state drawing (SSD). These processing variables include screw rotation speed during extrusion, fibre take-up speed, molecular weight, draw-ratio, and drawing temperature. As-spun PET production using a single-screw extrusion process was first optimized to induce an optimal polymer microstructure for subsequent drawing processes. It was found that less crystallization which occurred during this process would lead to better drawability, higher draw-ratio, and mechanical properties in the subsequent SSD process. Then the effect of drawing temperature (DT) in uniaxial two-stage SSD process was studied to understand how DT (< or close to or close to ) would affect the crystallization, draw-ratio, and final mechanical properties of PET. The designed process in current work is simulated to an industrial production process for PET fibres; therefore, results and analysis in this paper have significant importance for industrial production. Jian Min Zhang, Qingsong Hua, Christopher T. Reynolds, Yuling Zhao, Zuoqiang Dai, Emiliano Bilotti, Jie Tang, and Ton Peijs Copyright © 2017 Jian Min Zhang et al. All rights reserved. Fabrication and Assessment of ZnO Modified Polyethersulfone Membranes for Fouling Reduction of Bovine Serum Albumin Thu, 19 Jan 2017 00:00:00 +0000 ZnO/PES composite membranes were fabricated by phase inversion method using DMAc as a solvent. The structure of ZnO was investigated using TEM, SEM, XRD, and TGA. TEM images of ZnO nanoparticles were well-defined, small, and spherically shaped with agglomerated nanoparticles particles of 50 nm. The SEM and XRD results were an indication that ZnO nanoparticles were present in the prepared ZnO/PES composites membranes. Contact angle measurements were used to investigate surface structures of the composite membranes. The amount of ZnO nanoparticles on PES membranes was varied to obtain the optimal performance of the composite membranes in terms of pure water flux, flux recovery, and fouling resistance using the protein bovine serum albumin (BSA) as a model organic foulant. The results showed that addition of ZnO to PES membranes improved the hydrophilicity, permeation, and fouling resistance properties of the membranes. Pure water flux increased from a low of 250 L/m2h for the neat membrane to a high of 410 L/m2h for the composite membranes. A high flux recovery of 80–94% was obtained for the composite membranes. The optimal performance of the composite membranes was obtained at 1.5 wt% of ZnO. Tshepo Duncan Dipheko, Kgabo Philemon Matabola, Kate Kotlhao, Richard M. Moutloali, and Michael Klink Copyright © 2017 Tshepo Duncan Dipheko et al. All rights reserved. Combined Effects of Curing Temperatures and Alkaline Concrete on Tensile Properties of GFRP Bars Thu, 19 Jan 2017 00:00:00 +0000 A significant number of studies have been conducted on the tensile properties of GFRP bars embedded in concrete under different environments. However, most of these studies have been experimentally based on the environmental immersion test after standard-curing and the lack of influence on the tensile properties of GFRP bars embedded in concrete during the curing process of concrete. This paper presents the results of the microscopic structures through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and tensile properties of GFRP bars, which were employed to investigate the combined effects of curing temperatures and alkaline concrete on tensile properties of GFRP bars. The results showed that the higher curing temperature aggravated the influence of the alkaline concrete environment on GFRP bars but did not change the mechanisms of mechanical degradation of the GFRP bars. The influence of different curing temperatures on the tensile strength of GFRP bars was different between the bare bar and bars in concrete. Finally, the exponential correlation equation of two different test methods was established, and the attenuation ratio of the tensile strength of GFRP bars embedded in concrete under different curing temperatures was predicted by the bare test. Wen-rui Yang, Xiong-jun He, Kai Zhang, Yang Yang, and Li Dai Copyright © 2017 Wen-rui Yang et al. All rights reserved. Empirical Validation of Heat Transfer Performance Simulation of Graphite/PCM Concrete Materials for Thermally Activated Building System Wed, 18 Jan 2017 08:10:59 +0000 To increase the heat capacity in lightweight construction materials, a phase change material (PCM) can be introduced to building elements. A thermally activated building system (TABS) with graphite/PCM concrete hollow core slab is suggested as an energy-efficient technology to shift and reduce the peak thermal load in buildings. An evaluation of heat storage and dissipation characteristics of TABS in graphite/PCM concrete has been conducted using dynamic simulations, but empirical validation is necessary to acceptably predict the thermal behavior of graphite/PCM concrete. This study aimed to validate the thermal behavior of graphite/PCM concrete through a three-dimensional transient heat transfer simulation. The simulation results were compared to experimental results from previous studies of concrete and graphite/PCM concrete. The overall thermal behavior for both materials was found to be similar to experiment results. Limitations in the simulation modeling, which included determination of the indoor heat transfer coefficient, assumption of constant thermal conductivity with temperature, and assumption of specimen homogeneity, led to slight differences between the measured and simulated results. Jin-Hee Song, Hye-Sun Jin, Su-Gwang Jeong, Sumin Kim, Seung-Yeong Song, and Jae-Han Lim Copyright © 2017 Jin-Hee Song et al. All rights reserved. The Use of Biodiesel Residues for Heat Insulating Biobased Polyurethane Foams Wed, 18 Jan 2017 07:08:11 +0000 The commercial and biobased polyurethane foams (PUF) were produced and characterized in this study. Commercial polyether polyol, crude glycerol, methanol-free crude glycerol, and pure glycerol were used as polyols. Crude glycerol is byproduct of the biodiesel production, and it is a kind of biofuel residue. Polyol blends were prepared by mixing the glycerol types and the commercial polyol with different amounts, 10 wt%, 30 wt%, 50 wt%, and 80 wt%. All types of polyol blends were reacted with polymeric diphenyl methane diisocyanates (PMDI) for the production of rigid foams. Thermal properties of polyurethane foams are examined by thermogravimetric analysis (TGA) and thermal conductivity tests. The structures of polyurethane foams were examined by Fourier Transformed Infrared Spectroscopy (FTIR). Changes in morphology of foams were investigated by Scanning Electron Microscopy (SEM). Mechanical properties of polyurethane foams were determined by compression tests. This study identifies the critical aspects of polyurethane foam formation by the use of various polyols and furthermore offers new uses of crude glycerol and methanol-free crude glycerol which are byproducts of biodiesel industry. Nihan Özveren and M. Özgür Seydibeyoğlu Copyright © 2017 Nihan Özveren and M. Özgür Seydibeyoğlu. All rights reserved. Bond-Slip Models for FPR-Concrete Interfaces Subjected to Moisture Conditions Wed, 18 Jan 2017 00:00:00 +0000 Environmental related durability issues have been of great concerns in the structures strengthened with the fiber reinforced polymers (FRPs). In marine environment, moisture is one of the dominant factors that adversely affect the material properties and the bond interfaces. Several short-term and long-term laboratory experimental investigations have been conducted to study such behaviors but, still, there are insufficient constitutive bond models which could incorporate moisture exposure conditions. This paper proposed a very simple approach in determining the nonlinear bond-slip models for the FRP-concrete interface considering the effect of moisture conditions. The proposed models are based on the strain results of the experimental investigation conducted by the authors using 6 different commercial FRP systems exposed to the moisture conditions for the maximum period of 18 months. The exposure effect in the moisture conditions seems to have great dependency on the FRP system. Based on the contrasting differences in the results under moisture conditions, separate bond-slip models have been proposed for the wet-layup FRP and prefabricated FRP systems. As for the verification of the proposed model under moisture conditions, predicted pull-out load was compared with the experimental pull-out load. The results showed good agreement for all the FRP systems under investigation. Justin Shrestha, Dawei Zhang, and Tamon Ueda Copyright © 2017 Justin Shrestha et al. All rights reserved. MG-63 Cell Proliferation with Static or Dynamic Compressive Stimulation on an Auxetic PLGA Scaffold Sun, 15 Jan 2017 11:04:48 +0000 The effect of dynamic compressive stimulation on MG-63 cell proliferation on an auxetic PLGA scaffold was investigated. The estimated Poisson ratio of the prepared auxetic scaffold specimens was approximately (−)0.07, while the Poisson ratio estimated for conventional scaffold specimens was (+)0.12 under 10% strain compression on average. Three stimulus groups were examined: control (no stimulation), static compression, and dynamic compression. In preparation for proliferation testing, cells were seeded at 2.2 × 105 cells/80 μL on each scaffold specimen. The average proliferation rates of the static and dynamic groups were higher than those of the control group: 13.4% and 25.5% higher at culture day 1, 34.7% and 56.2% at culture day 3, and 17.5% and 43.0% at culture day 5, respectively. The static and dynamic group results at culture day 5 were significantly different (). Moreover, proliferation rate of the dynamic stimulation group was 1.22 times higher than that of the static group (). Conclusively, proliferation of osteoblast-like cells was enhanced through compressive stimulation, but the enhancement was maximal with dynamic compressive stimulation of auxetic scaffolds. Myeong Jin Kim, Hong Jin Choi, Jongman Cho, Jung Bok Lee, Hak-Joon Sung, and Jeong Koo Kim Copyright © 2017 Myeong Jin Kim et al. All rights reserved. Fatigue Crack Propagation Behavior of RC Beams Strengthened with CFRP under High Temperature and High Humidity Environment Sun, 15 Jan 2017 00:00:00 +0000 Numerical and experimental methods were applied to investigate fatigue crack propagation behavior of reinforced concrete (RC) beams strengthened with a new type carbon fiber reinforced polymer (CFRP) named as carbon fiber laminate (CFL) subjected to hot-wet environment. -integral of a central crack in the strengthened beam under three-point bending load was calculated by ABAQUS. In finite element model, simulation of CFL-concrete interface was based on the bilinear cohesive zone model under hot-wet environment and indoor atmosphere. And, then, fatigue crack propagation tests were carried out under high temperature and high humidity (50°C, 95% R · H) environment pretreatment and indoor atmosphere (23°C, 78% R · H) to obtain curves and crack propagation rate, , of the strengthened beams. Paris-Erdogan formula was developed based on the numerical analysis and environmental fatigue tests. Dongyang Li, Peiyan Huang, Guang Qin, Xiaohong Zheng, and Xinyan Guo Copyright © 2017 Dongyang Li et al. All rights reserved. Antibacterial Activity and Physical Properties of Fish Gelatin-Chitosan Edible Films Supplemented with D-Limonene Thu, 12 Jan 2017 00:00:00 +0000 Fish gelatin-chitosan edible films with D-limonene were successfully prepared, which exhibited exceptional mechanical properties and antimicrobial activity. It has been demonstrated that water-soluble chitosan, fish gelatin, and D-limonene could be a candidate precursor to prepare low cost and high-performance edible food packaging material. The results showed that D-limonene in the films could effectively resist the penetration of light and water because of its hydrophobicity. Moreover, the elongation at break (EAB) increased with the addition of D-limonene, which indicated that D-limonene served as a strong plasticizer for the film. Microscopic characterization showed that D-limonene was uniformly distributed in the as-prepared film. And we found that the film exhibited strong antibacterial activity against Escherichia coli (E. coli). All the results indicate that the as-prepared film could be a promising food packaging. Yunzhen Yao, Ding Ding, Hongyuan Shao, Qifan Peng, and Yaqin Huang Copyright © 2017 Yunzhen Yao et al. All rights reserved. Effects of pH on the Shape of Alginate Particles and Its Release Behavior Mon, 09 Jan 2017 13:42:15 +0000 A vast majority of alginate particles exist as spheres in most practical uses, and both the particle shape and size are the key factors dominating the applications and performance of alginate gels. Therefore, it becomes an issue of great interest to investigate the aspheric alginate particles. As the first step, various shaped alginate particles were formed due to various pH values in gelation solutions. It was experimentally demonstrated that a low pH brought about an oblate shape, and particularly lower concentrations of both alginate and divalent cations resulted in a flattened oblate shape. Ba2+ acting as a cross-linker had a less impact on the particle shape than Ca2+ due to a higher affinity in alginate intermolecular cross-linking. With a larger surface area, an oblate particle offered a higher release rate than a spheric one. Jui-Jung Chuang, Yu-Ya Huang, Szu-Hsuan Lo, Tzu-Fang Hsu, Wen-Ying Huang, Shu-Ling Huang, and Yung-Sheng Lin Copyright © 2017 Jui-Jung Chuang et al. All rights reserved. A Study on the Effectiveness of the Horizontal Shading Device Installation for Passive Control of Buildings in South Korea Mon, 09 Jan 2017 00:00:00 +0000 In South Korea, the evaluation criteria for installing shading devices are defined by regulations, but the standards of design methods are not clearly established. The installation of shading devices has become mandatory for some public buildings due to revised regulations. Therefore, a design of horizontal shading device is required, and indoor environmental problems which may occur due to their installation should also be taken into consideration. This research aimed to propose a design which takes into account the energy consumption which may occur if the horizontal shading device is installed and suggests an improved design method of horizontal shading devices when they are installed. Consequently, it was confirmed that as the protrusion of the horizontal shading device becomes longer, the incoming daylight is reduced and the indoor intensity of illumination becomes lower, and thus more lighting energy may be consumed in a room where the shading device is installed than in the one where it is not. Therefore, annual energy consumption was calculated by applying the lighting control and it was found that the total energy consumption decreased by the reduction of air-conditioning and fans and lighting energy consumption. Seok-Hyun Kim, Kyung-Ju Shin, Hyo-Jun Kim, and Young-Hum Cho Copyright © 2017 Seok-Hyun Kim et al. All rights reserved. Mechanical Properties of Steel-FRP Composite Bars under Tensile and Compressive Loading Tue, 03 Jan 2017 11:38:28 +0000 The factory-produced steel-fiber reinforced polymer composite bar (SFCB) is a new kind of reinforcement for concrete structures. The manufacturing technology of SFCB is presented based on a large number of handmade specimens. The calculated stress-strain curves of ordinary steel bar and SFCB under repeated tensile loading agree well with the corresponding experimental results. The energy-dissipation capacity and residual strain of both steel bar and SFCB were analyzed. Based on the good simulation results of ordinary steel bar and FRP bar under compressive loading, the compressive behavior of SFCB under monotonic loading was studied using the principle of equivalent flexural rigidity. There are three failure modes of SFCB under compressive loading: elastic buckling, postyield buckling, and no buckling (ultimate compressive strength is reached). The increase in the postyield stiffness of SFCB can delay the postyield buckling of SFCB with a large length-to-diameter ratio, and an empirical equation for the relationship between the postbuckling stress and is suggested, which can be used for the design of concrete structures reinforced by SFCB to consider the effect of reinforcement buckling. Zeyang Sun, Yu Tang, Yunbiao Luo, Gang Wu, and Xiaoyuan He Copyright © 2017 Zeyang Sun et al. All rights reserved. Absorbed Pb2+ and Cd2+ Ions in Water by Cross-Linked Starch Xanthate Tue, 03 Jan 2017 07:53:53 +0000 A cross-linked starch xanthate was prepared by graft copolymerization of acrylamide and sodium acrylate onto starch xanthate using potassium persulfate and sodium hydrogen sulfite initiating system and N,N′-methylenebisacrylamide as a cross-linker. As this kind of cross-linked potato starch xanthate can effectively absorb heavy metal ions, it was dispersed in aqueous solutions of divalent heavy metal ions (Pb2+ and Cd2+) to investigate their absorbency by the polymer. Factors that can influence absorbency were investigated, such as the ratio of matrix to monomers, the amount of initiator and cross-linker, pH, and the concentration of metal ions. Results were reached and conclusion was drawn that the best synthetic conditions for the polymer adsorbing Pb2+ and Cd2+ were as follows: the quality ratio of matrix to monomers was 1 : 12 and 1 : 11, the amount of initiator was 2.4% and 3.2% of matrix, and the amount of cross-linker was 12 mg and 13 mg. When the initial concentration of ions was 10 mg/L, the highest quantities of adsorption of Pb2+ and Cd2+ were 47.11 mg/g and 36.55 mg/g. Adsorption mechanism was discussed by using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) test, and adsorption kinetic simulation. Kai Feng and Guohua Wen Copyright © 2017 Kai Feng and Guohua Wen. All rights reserved. Effects of α-ZrP on Crystallinity and Flame-Retardant Behaviors of PA6/MCA Composites Tue, 03 Jan 2017 00:00:00 +0000 Novel flame-retardant Polyamide6/Melamine cyanurate-alpha-zirconium phosphate (PA6/MCA-α-ZrP) composites were prepared via the incorporation of the modified MCA (MCA-α-ZrP) into PA6. MCA-α-ZrP were synthesized through the self-assembly of α-ZrP, Melamine (ME), and cyanuric acid (CA) molecules. The results of differential scanning calorimetry (DSC) and X-ray diffraction (XRD) showed that the incorporation of enough α-ZrP (30 wt% MCA) caused the increased crystallinity of PA6 and tended to form phase. The thermogravimetric analysis (TGA) and heat distortion temperature (HDT) test illustrated that the α-ZrP could increase the residue and HDT values of PA6/MCA and showed a synergistic effect with MCA. The combination of MCA and α-ZrP caused the enhancement of vertical burning test (UL-94) rating. Cone calorimeter test (CCT) gave clear evidences that PA6/MCA-10α-ZrP composites with low heat release rate (HRR), low total heat release (THR), and high amounts of char residues after combustion compared with PA6/MCA and PA6/MCA-30α-ZrP. What is more, excellent mechanical properties were kept even though MCA and α-ZrP were dispersed not as good as expected. Yuanfang Xiao, Jiayou Xu, Siwen Huang, and Haiming Deng Copyright © 2017 Yuanfang Xiao et al. All rights reserved. Microwave Irradiation Assisted Preparation of Chitosan Composite Microsphere for Dye Adsorption Mon, 02 Jan 2017 12:28:22 +0000 Chitosan-activated carbon composite microspheres were prepared by emulsion cross-linking method and its adsorption properties for methyl orange were studied. Chitosan solution was mixed with activated carbon powder and then chitosan was cross-linked by epichlorohydrin under microwave irradiation. SEM photos show that the composite microspheres have diameters of 200–400 μm and activated carbon powder dispersed on the surface of composite microsphere. FTIR spectrum indicates chitosan is successfully cross-linked. Microwave irradiation can effectively shorten the cross-linking time. Composite microspheres have enhanced dye adsorption capacity for methyl orange compared to chitosan microspheres. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Isotherm studies show that the isotherm adsorption equilibrium is better described by Freundlich isotherm. Regeneration results show that adsorption capacity of composite microsphere decreased about 5.51% after being reused for three times. These results indicated that chitosan-activated carbon composite microsphere has potential application in the removal of dye from wastewaters. Xiaoyu Chen and Lindun He Copyright © 2017 Xiaoyu Chen and Lindun He. All rights reserved. Experimental Study on Bond Behavior of FRP-Concrete Interface in Hygrothermal Environment Thu, 29 Dec 2016 14:41:57 +0000 As the technique of fiber-reinforced polymer (FRP) composite material strengthened reinforced concrete structures is widely used in the field of civil engineering, durability of the strengthened structures has attracted more attention in recent years. Hygrothermal environment has an adverse effect on the bond behavior of the interface between FRP and concrete. This paper focuses on the bond durability of carbon fiber laminate- (CFL-) concrete interface in hygrothermal condition which simulates the climate characteristic in South China. Twenty 100 mm × 100 mm × 720 mm specimens were divided into 6 groups based on different temperature and humidity. After pretreatment in hygrothermal environment, the specimens were tested using double shear method. Strain gauges bonded along the CFL surface and linear variation displacement transducers (LVDTs) were used to measure longitudinal strains and slip of the interface. Failure mode, ultimate capacity, load-deflection relationship, and relative slip were analyzed. The bond behavior of FRP-concrete interface under hygrothermal environment was studied. Results show that the ultimate bearing capacity of the interface reduced after exposure to hygrothermal environments. The decreasing ranges were up to 27.9% after exposure at high temperature and humidity (60°C, 95% RH). The maximum strains () of the specimens pretreated decreased obviously which indicated decay of the bond behavior after exposure to the hygrothermal environment. X. H. Zheng, P. Y. Huang, X. Y. Guo, and J. L. Huang Copyright © 2016 X. H. Zheng et al. All rights reserved. Alginate: Current Use and Future Perspectives in Pharmaceutical and Biomedical Applications Wed, 28 Dec 2016 13:47:33 +0000 Over the last decades, alginates, natural multifunctional polymers, have increasingly drawn attention as attractive compounds in the biomedical and pharmaceutical fields due to their unique physicochemical properties and versatile biological activities. The focus of the paper is to describe biological and pharmacological activity of alginates and to discuss the present use and future possibilities of alginates as a tool in drug formulation. The recent technological advancements with using alginates, issues related to alginates suitability as matrix for three-dimensional tissue cultures, adjuvants of antibiotics, and antiviral agents in cell transplantation in diabetes or neurodegenerative diseases treatment, and an update on the antimicrobial and antiviral therapy of the alginate based drugs are also highlighted. Marta Szekalska, Agata Puciłowska, Emilia Szymańska, Patrycja Ciosek, and Katarzyna Winnicka Copyright © 2016 Marta Szekalska et al. All rights reserved. Use of Oxalic-Acid-Modified Stellerite for Improving the Filter Capability of PM2.5 of Paper Composed of Bamboo Residues Tue, 27 Dec 2016 08:35:10 +0000 In this study, pulping conditions for kraft pulping of bamboo residues were investigated, predominantly focusing on cooking temperature and time during pulping. Oxalic acid and cationic starch were used for the modification of natural stellerite, and the use of modified stellerite for preparing filter paper for PM2.5 filtration was investigated. The optimal pulping technology of bamboo residues was established based on the following experimental parameters: liquor ratio of 1 : 5.5, cooking temperature of 160°C, and a holding time of 2 h. Modification by oxalic acid resulted in the promotion of pore formation at the stellerite surfaces and induced the microscopic changes. Nevertheless, paper strength remained practically unchanged after the addition of fillers, indicating that the cationic starch preblend method is a promising technique for papermaking because it enhances the strength properties of paper. With the variation in the addition of modified stellerite from 3 to 15%, while simultaneously maintaining the basis weight constant at 60 gm−2, the filtration efficiency of paper sheets first increased and then decreased later; thus the optimum stellerite content was found to be 9%. Filtration efficiency was suggested to be affected by gas flowing velocity. Hua Chen, Jian Lou, Fei Yang, Jia-nan Zhou, Yan Zhang, and Huabo Yao Copyright © 2016 Hua Chen et al. All rights reserved. Plasma Treatment of Agave Fiber Powder and Its Effect on the Mechanical and Thermal Properties of Composites Based on Polyethylene Tue, 27 Dec 2016 08:25:47 +0000 Composites based on low-density polyethylene (LDPE) were prepared with Agave fiber powder (AFP) that was coated by plasma polymerization process using ethylene gas. Treated and pristine AFP were analyzed by infrared spectroscopy, scanning electron microscopy, and contact water angle for the assessment of surface properties. The polymer composites were prepared by melt mixing using 0, 5, 10, and 20 wt% of AFP and their mechanical and thermal properties were measured. Dispersion evaluation in water confirmed that the AFP treated changed from hydrophilic to hydrophobic behavior and it was also corroborated with water contact angle tests. The addition of treated and untreated AFP (200 mesh) at 20 wt% promotes an increase of Young’s modulus of the composites of up to 60% and 32%, respectively, in relation to the neat matrix. Also, an increase of crystallinity of LDPE was observed by the addition of treated and untreated AFP; however no significant effect on the crystallization temperature was observed in LDPE containing AFP. Florentino Soriano Corral, Luis Antonio Calva Nava, Ernesto Hernández Hernández, José Francisco Hernández Gámez, María Guadalupe Neira Velázquez, María Isabel Montalvo Sierra, Pablo González Morones, and Ramón Enrique Díaz De León Gómez Copyright © 2016 Florentino Soriano Corral et al. All rights reserved. Kinetic Analysis of the Thermal Decomposition of Latex Foam according to Thermogravimetric Analysis Mon, 26 Dec 2016 14:10:02 +0000 The thermal decomposition of latex foam was investigated under nonisothermal conditions. Pieces of commercial mattress samples were subjected to thermogravimetric analysis (TG) over a heating range from 5°C min−1 to 20°C min−1. The morphology of the latex foam before and after combustion was observed by scanning electron microscopy (SEM), and the primary chemical composition was investigated via infrared spectroscopy (FT-IR). The kinetic mechanism and relevant parameters were calculated. Results indicate that the decomposition of latex foam in the three major degradation phases is controlled by third-order reaction (F3) and by Zhuravlev’s diffusion equation (D5). The mean values of each phase as calculated according to a single heating rate nonisothermal method are equal to 41.91 ± 0.06 kJ mol−1, 86.32 ± 1.04 kJ mol−1, and 19.53 ± 0.11 kJ mol−1, respectively. Correspondingly, the preexponential factors of each phase are equal to 300.39 s−1, 2355.65 s−1, and 27.90 s−1, respectively. The mean activation energy and preexponential factor of latex foam estimated according to multiple heating rates and a nonisothermal method are 92.82 kJ mol−1 and 1.12 × 10−3 s−1, respectively. Hongwei Fan, Yongliang Chen, Dongmei Huang, and Guoqin Wang Copyright © 2016 Hongwei Fan et al. All rights reserved. Impact of Hydrolyzed Whey Protein on the Molecular Interactions and Cross-Linking Density in Whey Protein Isolate-Based Films Wed, 21 Dec 2016 09:09:00 +0000 The effect of the amount of hydrolyzed WPI (h-WPI) in WPI-based films on the technofunctional properties and structure of the films has not hitherto been systematically researched. The main objective of this study was therefore to explore the quantitative and qualitative molecular interactions and structures of these films. Different buffer systems were used for the solubility studies to obtain information about the qualitative molecular interactions. Swelling studies were performed to provide qualitative statements about the WPI network. In addition, the cross-linking density (CLD) of the WPI-based films was derived from the swelling tests. The measurements showed that increasing the h-WPI content decreases the CLD significantly. The CLD values of films with 0% and 50% h-WPI content were  molcm−3 and  molcm−3. The study indicates that noncovalent interactions have more influence on barrier properties than the cross-linking density through disulphide bonds. In general, the results of the swelling tests correlated with the solubility studies. Markus Schmid, Sandra Pröls, Daniel M. Kainz, Felicia Hammann, and Andreas Stäbler Copyright © 2016 Markus Schmid et al. All rights reserved. In Situ Carbon Coated LiNi0.5Mn1.5O4 Cathode Material Prepared by Prepolymer of Melamine Formaldehyde Resin Assisted Method Mon, 19 Dec 2016 09:29:31 +0000 Carbon coated spinel LiNi0.5Mn1.5O4 were prepared by spray-drying using prepolymer of melamine formaldehyde resin (PMF) as carbon source of carbon coating layer. The PMF carbon coated LiNi0.5Mn1.5O4 was characterized by XRD, SEM, and other electrochemical measurements. The as-prepared lithium nickel manganese oxide has the cubic face-centered spinel structure with a space group of Fd3m. It showed good electrochemical performance as a cathode material for lithium ion battery. After 100 discharge and charge cycles at 0.5 C rate, the specific discharge capacity of carbon coated LiNi0.5Mn1.5O4 was 130 mAh·g−1, and the corresponding capacity retention was 98.8%. The 100th cycle specific discharge capacity at 10 C rate of carbon coated LiNi0.5Mn1.5O4 was 105.4 mAh·g−1, and even the corresponding capacity retention was 95.2%. Wei Yang, Haifeng Dang, Shengzhou Chen, Hanbo Zou, Zili Liu, Jing Lin, and Weiming Lin Copyright © 2016 Wei Yang et al. All rights reserved. Surface Modification of Asymmetric Polysulfone/Polyethylene Glycol Membranes by DC Ar-Glow Discharge Plasma Sun, 18 Dec 2016 14:47:19 +0000 Polysulfone/polyethylene glycol (PSF/PEG) membranes were prepared by dry/wet phase inversion method. Effects of direct current glow discharge plasma using argon as working gas on morphological structures and gas separation properties of membranes were studied. Alteration of membrane characteristics were analyzed by various techniques like contact angle, scanning electron microscope, Fourier transform infrared spectroscopy, and dynamic mechanical thermal analysis. Gas separation properties were measured in terms of permeation and ideal O2/N2 selectivity. Results showed that hydrophilic and gas separation properties of PSF/PEG membranes increased by plasma surface modification. It was also shown that the dosage of PEG and plasma treatment affected the morphological structures and mechanical and gas separation properties. The macro voids and transmembrane structure disappeared with a little amount of PEG dosage. Pore size and mechanical strength tend to decrease with increasing PEG dosage up to 10 wt%. Glass transition temperature receded from 201.8 to 143.7°C for pure PSF and PSF/PEG with PEG dosage of 10 wt%. O2 and N2 gases permeation through the 10-minute plasma treated membranes tend to increase. However, the permeation strongly dispersed when treatment time was more extended. Chalad Yuenyao, Thawat Chittrakarn, Yutthana Tirawanichakul, and Suksawat Sirijarukul Copyright © 2016 Chalad Yuenyao et al. All rights reserved.