International Journal of Polymer Science The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Polyvinylpolypyrrolidone Supported Brønsted Acidic Catalyst for Esterification Sun, 04 Dec 2016 11:32:40 +0000 A polyvinylpolypyrrolidone (PVPP) supported Brønsted acidic catalyst (PVPP-BSHSO4) was prepared by coupling SO3H-functionalized polyvinylpolypyrrolidone with H2SO4 in this work. After the characterization through FT-IR, FESEM, TG, BET, and elemental analysis, it was found that 1,4-butane sultone (BS) and sulfuric acid reacted with PVPP and were immobilized on PVPP surface. The prepared PVPP-BSHSO4 catalyst shows high catalytic activity for a series of esterification reactions and could be separated from the reacted mixture easily. Moreover, this catalyst could be recycled and reused for six times without significant loss of catalytic performance. Song Wang and Chengcheng Tian Copyright © 2016 Song Wang and Chengcheng Tian. All rights reserved. Effect of Temperature Variation on Bond Characteristics between CFRP and Steel Plate Sun, 04 Dec 2016 09:00:46 +0000 In recent years, application of carbon fiber reinforced polymer (CFRP) composite materials in the strengthening of existing reinforced concrete structures has gained widespread attention, but the retrofitting of metallic buildings and bridges with CFRP is still in its early stages. In real life, these structures are possibly subjected to dry and hot climate. Therefore, it is necessary to understand the bond behavior between CFRP and steel at different temperatures. To examine the bond between CFRP and steel under hot climate, a total of twenty-one double strap joints divided into 7 groups were tested to failure at constant temperatures from 27°C to 120°C in this paper. The results showed that the joint failure mode changed from debonding along between steel and adhesive interface failure to debonding along between CFRP and adhesive interface failure as the temperature increased beyond the glass transition temperature () of the adhesive. The load carrying capacity decreased significantly at temperatures approaching or exceeding . The interfacial fracture energy showed a similar degradation trend. Analytical models of the ultimate bearing capacity, interfacial fracture energy, and bond-slip relationship of CFRP-steel interface at elevated temperatures were presented. Shan Li, Tao Zhu, Yiyan Lu, and Xiaojin Li Copyright © 2016 Shan Li et al. All rights reserved. Modification of Leather Split by In Situ Polymerization of Acrylates Thu, 01 Dec 2016 11:26:19 +0000 Leather split, the byproduct of leather manufacture, possesses low utility value because it has loose weave of collagen fibers and weak mechanical strengths. Herein, a practical and convenient method for increasing strengths of leather split was developed by one-step in situ polymerization. The structures and properties of polyacrylate/leather split composites were systematically investigated. The results suggested the monomers with an α-methyl and a proper straight-chain ester group, such as nBMA, can effectively modify the leather split. For leather split with a thickness of 1.6 mm, the rational processes for preparation of polyacrylate/leather split composite are that monomer and split were stirred in a drum for 4 hours for full permeation and then the split was heated in anaerobic condition at 45°C for 30 min. The tensile strength, tear strength, and elongation at break of the optimized PnBMA/split composite were 18.72 MPa, 62.73 N/mm, and 46.02%, respectively. With these mechanical properties, the split after modification can be well used as leather for making shoes, bags, gloves, and clothing. Weixing Xu, Jianfei Zhou, Ya’nan Wang, and Bi Shi Copyright © 2016 Weixing Xu et al. All rights reserved. Synthesis, Optimization, Property, Characterization, and Application of Dialdehyde Cross-Linking Guar Gum Thu, 01 Dec 2016 08:34:15 +0000 Dialdehyde cross-linking guar gum (DCLGG), as a novel material, was synthesized using phosphorus oxychloride as a cross-linking reagent, sodium periodate as an oxidant, and ethanol as a solvent through keeping the original particle form of guar gum. The process parameters such as the reaction temperature, reaction time, pH, amount of sodium periodate, and amount of ethanol were optimized by the response surface methodology in order to obtain the regression model of the oxidization. The covalent binding of L-asparagine onto the surfaces of DCLGG was further investigated. The results showed that the best technological conditions for preparing DCLGG were as follows: reaction temperature = 40°C, reaction time = 3.0 h, pH = 4.0, and amount of ethanol = 74.5%. The swelling power of DCLGG was intermediate between cross-linking guar gum and dialdehyde guar gum. The cross-linking and dialdehyde oxidization reduced the viscosity of GG. The cross-liking reduced the melting enthalpy of GG. However, the oxidization increased melting enthalpy of ACLGG. The thermal stability of GG was increased by cross-linking or oxidization. The variation of the onset decomposition temperature and end decomposition temperature of GG was not consistent with thermal stability of GG. L-asparagine could be chemically bound well by DCLGG through forming Schiff base under the weak acidity. The maximum adsorption capacity of L-asparagine on DCLGG with aldehyde content of 56.2% reached 21.9 mg/g. Tang Hongbo, Li Yanping, Zhang Wen, and Dong Siqing Copyright © 2016 Tang Hongbo et al. All rights reserved. Laser-Based Joining of Thermoplastics to Metals: Influence of Varied Ambient Conditions on Joint Performance and Microstructure Thu, 24 Nov 2016 14:20:42 +0000 Laser-based joining of thermoplastics to metals shows a great potential for functional design especially in terms of lightweight constructions. In the joining process, the joining speed and the energy per unit length, respectively, show an influence on time-temperature profiles measured in the joining zone. The time-temperature profile affects the joining zone and consequently the joint behavior in mechanical testing. In the current investigation, the joining zone was characterized by the melting layer. Moreover, the mechanical properties of the joint by tensile shear testing and the fracture mode were investigated. Based on the results obtained, three sets of joining speeds/energies per unit length with different mechanical behaviors were selected for further investigations under varied ambient conditions. Thereby, the influence of outdoor weathering as well as aging above the glass transition temperature of the plastic part on the joint’s performance was compared with the nonaged joints. Klaus Schricker, Martin Stambke, Jean Pierre Bergmann, and Kevin Bräutigam Copyright © 2016 Klaus Schricker et al. All rights reserved. Biocompatible and Biodegradable Ultrafine Nanoparticles of Poly(Methyl Methacrylate-co-Methacrylic Acid) Prepared via Semicontinuous Heterophase Polymerization: Kinetics and Product Characterization Tue, 22 Nov 2016 14:08:46 +0000 Ultrafine nanoparticles, less than 10 nm in mean diameter, of the FDA approved copolymer methyl methacrylate- (MMA-) co-methacrylic acid (MAA), 2/1 (mol/mol), were prepared. The method used for the preparation of these particles stabilized in a latex containing around 11% solids includes the dosing of the monomers mixture on a micellar solution preserving monomer starved conditions. It is thought that the operation at these conditions combined with the hydrophilicity of MMA and MAA units favors the formation of ultrafine particles; the propagation reaction carried out within so small compartments renders copolymer chains rich in syndiotactic units very likely as consequence of the restricted movements of the end propagation of the chains. Because of their biocompatibility and biodegradability as well as their extremely small size these nanoparticles could be used as vehicles for improved drug delivery in the treatment of chronic-degenerative diseases. Henned Saade, María de Lourdes Guillén, Judith Cabello Romero, Jesús Cepeda, Anna Ilyna, Salvador Fernández, Francisco Javier Enríquez-Medrano, and Raúl Guillermo López Copyright © 2016 Henned Saade et al. All rights reserved. Hierarchical Structured Polymeric Materials in Nanotechnology Mon, 21 Nov 2016 07:59:20 +0000 Xiao Gong, Tairong Kuang, Yiwen Li, Xiaohong Hu, and Ming Zhang Copyright © 2016 Xiao Gong et al. All rights reserved. Synthesis and Characterization of Molecular Imprinting Polymer Microspheres of Cinnamic Acid: Extraction of Cinnamic Acid from Spiked Blood Plasma Sun, 20 Nov 2016 08:13:50 +0000 The molecular imprinting technique is used to create the molecularly imprinted polymers (MIPs) with higher binding capacity towards the template. In this research precipitation polymerization method with noncovalent approach was used to synthesize imprinted polymer microspheres. The polymerization reaction was conducted in a flask containing acetonitrile as a porogen, cinnamic acid as a template (T), acrylic acid (AA) as a monomer, divinylbenzene (DVB) as a cross-linker, and azobisisobutyronitrile as an initiator. The polymer particles were characterized by using SEM and FTIR. The rebinding efficiency was conducted by batch binding assay and the results were monitored by using HPLC. The batch binding results suggested MIP1 (T : AA : DVB, 1 : 6 : 20 molar ratio) is most suitable composition for the rebinding of cinnamic acid. The highly selective polymer (MIP1) was used for the extraction of cinnamic acid from human plasma. The extraction efficiency of imprinted polymer of cinnamic acid from spiked plasma was above 75%. Alvin Leong Joke Chow and Showkat Ahmad Bhawani Copyright © 2016 Alvin Leong Joke Chow and Showkat Ahmad Bhawani. All rights reserved. Processing of Polypropylene-Organic Montmorillonite Nanocomposite by Equal Channel Multiangular Extrusion Thu, 17 Nov 2016 14:31:34 +0000 By the example of polypropylene-organic montmorillonite composite (PP-OMMT), the abilities of the method of equal channel multiangular extrusion have been studied with respect to the modification of the structure and the properties of polymeric nanocomposites. With using X-ray structure analysis, TEM, DSC, and dilatometry, it has been demonstrated that this kind of processing provides an additional intercalation of the polymer into OMMT tactoids with the succeeding exfoliation and facilitates an increase in the aspect ratio, the degree of platelet orientation, the crystalline lamellar thickness, and a decrease in the dispersion of the crystallite thickness, as well as the formation of biaxial orientation of the OMMT and PP crystals. The observed structure rearrangements determine enhanced microhardness, ductility, and the heat distortion temperature of the PP-OMMT composite. V. A. Beloshenko, A. V. Voznyak, Yu. V. Voznyak, L. A. Novokshonova, V. G. Grinyov, and V. G. Krasheninnikov Copyright © 2016 V. A. Beloshenko et al. All rights reserved. Antibacterial Additive for Polystyrene Based on Silver Nanoparticles Supported on Titanium Dioxide Wed, 16 Nov 2016 12:00:45 +0000 Silver nanoparticles supported on titanium dioxide nanoparticles (Ag/TiO2) were incorporated and evaluated as antibacterial additive for polystyrene materials. These particles were synthesized using a deposition-precipitation method by adding silver nitrate as metallic precursor, sodium hydroxide as reducing agent, and commercial TiO2 (P25) as support. Rectangular pieces of polystyrene (PS) containing 100, 300, 500, and 700 ppm (wt.%) of the additive were made using an extrusion-injection molding process, and they were evaluated for their antibacterial properties against Escherichia coli using the Pour Plate method. Particles were distributed on the PS surface, and PS pieces presented a good antibacterial efficiency at 100, 300, and 500 ppm and decreased for 700 ppm due to an additive agglomeration on the PS surface. These results validate the antibacterial properties of Ag/TiO2, determine a concentration limit at which the additive is well distributed on the PS surface, and assess the importance of Ag in this system. Miguel A. Waldo-Mendoza, Lucía Martínez-Jothar, Socorro Oros-Ruiz, E. G. Villabona-Leal, Luis Manuel Céspedes-Covarrubias, Zoe V. Quiñones-Jurado, Eduardo Ortega, and Elías Pérez Copyright © 2016 Miguel A. Waldo-Mendoza et al. All rights reserved. Synthesis of High cis-Polybutadiene in Styrene Solution with Neodymium-Based Catalysts: Towards the Preparation of HIPS and ABS via In Situ Bulk Polymerization Mon, 14 Nov 2016 12:26:05 +0000 In a first step, 1,3-butadiene was selectively polymerized at 60°C in styrene as solvent using NdV3/DIBAH/EASC as the catalyst system. The catalyst system activation process, the addition order of monomers and catalyst components, and the molar ratios [Al]/[Nd] and [Cl]/[Nd] were studied. The catalyst system allowed the selective 1,3-butadiene polymerization, reaching conversions between 57.5 and 88.1% with low polystyrene contents in the order of 6.3 to 15.4%. Molecular weights ranging from 39,000 to 150,000 g/mol were obtained, while cis-1,4 content was found in the interval of 94.4 to 96.4%. On the other hand, the glass transition temperatures of synthesized materials were established in the range of −101.9 to −107.4°C, explained by the presence of polystyrene segments in the polybutadiene chains; in the same sense, the polybutadienes did not show the typical melting endotherm of high cis-polybutadienes. In a second step, the resulting styrene/high cis-1,4 polybutadiene solutions were used to synthesize ABS (adding a fraction of acrylonitrile monomer) and HIPS via in situ bulk polymerizations and the results were discussed in terms of morphological development, molecular parameters, dynamical mechanical behavior, and mechanical properties. Ramón Díaz de León, Florentino Soriano Corral, Francisco Javier Enríquez-Medrano, Gabriela Bosques Ibarra, Patricia de León Martínez, Francisco Hernández Gámez, Héctor Ricardo López-González, and Luis Francisco Ramos de Valle Copyright © 2016 Ramón Díaz de León et al. All rights reserved. Effect of Die Head Temperature at Compounding Stage on the Degradation of Linear Low Density Polyethylene/Plastic Film Waste Blends after Accelerated Weathering Sun, 13 Nov 2016 12:40:26 +0000 Accelerated weathering test was performed on blends of linear low density polyethylene (LLDPE) and plastic film waste constituting the following percentages of polyolefin polymers (wt.%): LLDPE (46%), low density polyethylene (LDPE, 51%), high density polyethylene (HDPE, 1%), and polypropylene (PP, 2%). Compounded blends were evaluated for their mechanical and physical (optical) properties. The impact of photodegradation on the formulated blends was studied, and loss of mechanical integrity was apparent with respect to both the exposure duration to weathering and waste content. The effect of processing conditions, namely, the die head temperature (DHT) of the blown-film assembly used, was investigated in this work. It was witnessed that surpassing the melting point of the blends constituting polymers did not always result in a synergistic behaviour between polymers. This was suspected to be due to the loss of amorphous region that polyolefin polymers get subjected to with UV exposure under weathering conditions and the effect of the plastic waste constituents. The total change in colour () did not change with respect to DHT or waste content due to rapid change degradation on the material’s surface. Haze (%) and light transmission (%) decreased with the increase in waste content which was attributed to lack of miscibility between constituting polymers. S. M. Al-Salem, N. M. Al-Dousari, G. Joseph Abraham, M. Aromin D’Souza, O. A. Al-Qabandi, and W. Al-Zakri Copyright © 2016 S. M. Al-Salem et al. All rights reserved. Chitosan-Based Coating with Antimicrobial Agents: Preparation, Property, Mechanism, and Application Effectiveness on Fruits and Vegetables Thu, 10 Nov 2016 06:15:32 +0000 Chitosan coating is beneficial to maintaining the storage quality and prolonging the shelf life of postharvest fruits and vegetables, which is always used as the carrier film for the antimicrobial agents. This review focuses on the preparation, property, mechanism, and application effectiveness on the fruits and vegetables of chitosan-based coating with antimicrobial agents. Chitosan, derived by deacetylation of chitin, is a modified and natural biopolymer as the coating material. In this article, the safety and biocompatible and antimicrobial properties of chitosan were introduced because these attributes are very important for its application. The methods to prepare the chitosan-based coating with antimicrobial agents, such as essential oils, acid, and nanoparticles, were developed by other researchers. Meanwhile, the application of chitosan-based coating is mainly due to its antimicrobial activity and other functional properties, which were investigated, introduced, and analyzed in this review. Furthermore, the surface and mechanical properties were also investigated by researchers and concluded in this article. Finally, the effects of chitosan-based coating on the storage quality, microbial safety, and shelf life of fruits and vegetables were introduced. Their results indicated that chitosan-based coating with different antimicrobial agents would probably have wide prospect in the preservation of fruits and vegetables in the future. Yage Xing, Qinglian Xu, Xingchen Li, Cunkun Chen, Li Ma, Shaohua Li, Zhenming Che, and Hongbin Lin Copyright © 2016 Yage Xing et al. All rights reserved. Recent Advances in Cellulose-Based Materials: Synthesis, Characterization, and Their Applications Mon, 07 Nov 2016 13:27:26 +0000 Xue-Ming Zhang, Ming-Guo Ma, Jun Yang, Zhouyang Xiang, Jie-Fang Zhu, and Yatimah Alias Copyright © 2016 Xue-Ming Zhang et al. All rights reserved. Upgrading Electrical, Mechanical, and Chemical Properties of CNTs/Polybond® Nanocomposites: Pursuit of Electroconductive Structural Polymer Nanocomplexes Mon, 31 Oct 2016 06:25:24 +0000 Electroconductive structural polymer-based nanocomposites (NCs) were prepared by incorporating carbon nanotubes (CNTs) into Polybond (PB) matrix via melt compounding technique. Chemical structure of NCs, investigated via Fourier transform infrared (FTIR) spectroscopy, corroborated successful grafting of CNTs functional groups onto PB chains. The morphology of NCs, as examined by scanning electron microscopy (SEM), ensured their optimum state of dispersion. Electrical conductivity, melting transition temperatures, mechanical properties, and chemical resistance of NCs were improved by incorporating CNTs into PB as established by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), high resistance meter (HRM), Universal Testing Machine (UTM), and chemical resistivity measurements, respectively. Muhammad Sarfraz Copyright © 2016 Muhammad Sarfraz. All rights reserved. Effect of Elastomeric Nanoparticles on Polystyrene/Organic Nanocomposites Sun, 30 Oct 2016 09:34:22 +0000 The rheological behavior of nanosheet composites and the effect of morphology between elastomeric nanofiber and nanosheet composites were studied using a Cross-Williamson model and critical volume concentration was investigated by percolation threshold theory for fiber and sheet morphologies. Nanofiber and nanosheet particles were synthesized by a cold vulcanization process using a S2Cl2 cross-linking reagent resulting from self-assembly of a PS-PI block copolymer. Nanofiber and nanosheet characterization was done by SEM. Rheological properties were measured and analyzed in terms of varying nanofiller and nanosheet loading from 0.5 to 10 wt%. For the nanofiber and nanosheet composites, the moduli were increased with increasing filler loading, whereas moduli of SI23 and SI43 composite decreased with increasing content. Both nanofiber and nanosheet composites showed a nanosized filler effect and their structural changes were between 5 and 10 wt%. Cross-Williamson three-parameter model was used to find zero-shear viscosity and relaxation time. Percolation threshold theory was used to study structural changes and calculate values. Sungwon Ma and Yonathan Thio Copyright © 2016 Sungwon Ma and Yonathan Thio. All rights reserved. PLA and PP Composite Nonwoven with Antimicrobial Activity for Filtration Applications Wed, 26 Oct 2016 11:17:47 +0000 The PLA (50% wt.)/PP (50% wt.), PLA (47.5% wt.)/PP (47.5% wt.)/paraffin (5% wt.), and PLA (47.25% wt.)/PP (47.25% wt.)/paraffin (5% wt.)/CuO·SiO2 (0.5% wt.) composite nonwovens were obtained in one-step process by using the melt-blown technique. Thermal properties (by the DSC method), physicomechanical parameters, specific surface area, the structure (by the SEM method), the elemental analysis (by the EDS method), and susceptibility to hydrolytic degradation (in alkaline and neutral media) were studied for all the obtained nonwovens. The antimicrobial properties of the composite nonwovens were determined by using dynamic contact conditions method, with three kinds of microorganisms applied. The DSC analysis of nonwovens revealed that the mixing of PLA and PP caused the decrease in homogeneity of both polymers, as well as a considerable increase in the PLA crystallization enthalpy. The paraffin and CuO·SiO2 addition to PLA/PP nonwoven generally improved the filtration properties and downgraded tensile strength. Among all the tested composite nonwovens, the PLA/PP/paraffin/CuO·SiO2 was the most and the PLA/PP/paraffin was the least susceptible to hydrolytic degradation in both media used in the study. The PLA/PP/paraffin/CuO·SiO2 composite nonwoven revealed strong antibacterial activity and slight activity against the yeast. Marta Łatwińska, Jadwiga Sójka-Ledakowicz, Jerzy Chruściel, and Maciej Piórkowski Copyright © 2016 Marta Łatwińska et al. All rights reserved. Antibacterial Nanocomposites Based on Fe3O4–Ag Hybrid Nanoparticles and Natural Rubber-Polyethylene Blends Mon, 24 Oct 2016 13:38:44 +0000 For the vulcanized natural rubber (NR), incorporation of silver nanoparticles (AgNPs) into the NR matrix did not exhibit the bactericidal property against Escherichia coli (E. coli). However, incorporation of AgNPs into polyethylene (PE) matrix showed good antibacterial activities to both Gram-negative and Gram-positive bacteria. In the present work, NR/PE (85/15) blends have been prepared by melt blending with presence of compatibilizer in an internal mixer. To possess antibacterial property, AgNPs (5–10 nm) or Fe3O4–Ag hybrid nanoparticles (FAgNPs, 8 nm/16 nm) were added into PE matrix before its blending with NR component. The tensile test indicated that the presence of compatibilizer in NR/PE blend significantly enhanced the tensile strength and elongation at break (up to 35% and 38% increases, resp.). The antibacterial activity test was performed by monitoring of the bacterial lag-log growth phases with the presence of nanocomposites in the E. coli cell culture reactor. The antibacterial test showed that the presence of FAgNPs in NR/PE blend had a better antibacterial activity than that obtained with the lone AgNPs. Two similar reasons were proposed: (i) the faster Ag+ release rate from the Fe3O4–Ag hybrid nanoparticles due to the electron transfer from AgNP to Fe3O4 nanoparticle and (ii) the fact that the ionization of AgNPs in hybrid nanostructure might be accelerated by Fe3+ ions. Thanh Dung Ngo, Thi My Hanh Le, The Huu Nguyen, Thien Vuong Nguyen, Tuan Anh Nguyen, Trong Lu Le, Thi Thai Nguyen, Thi Thanh Van Tran, Thi Bich Thao Le, and Ngoc Hai Doan Copyright © 2016 Thanh Dung Ngo et al. All rights reserved. Influence of Monomer Concentration on the Morphologies and Electrochemical Properties of PEDOT, PANI, and PPy Prepared from Aqueous Solution Mon, 24 Oct 2016 10:02:02 +0000 Poly(3,4-ethylenedioxyhiophene) (PEDOT), polyaniline (PANI), and polypyrrole (PPy) were prepared on indium tin oxide (ITO) substrate via potentiostatic from aqueous solutions containing monomer and lithium perchlorate. The concentration of monomers was varied between 1 and 10 mM. The effects of monomer concentration on the polymers formation were investigated and compared by using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) measurements. FTIR and Raman spectra showed no changes in the peaks upon the increment of the concentration. Based on the SEM images, the increment in monomer concentration gives significant effect on morphologies and eventually affects the electrochemical properties. PEDOT electrodeposited from 10 mM solution showed excellent electrochemical properties with the highest specific capacitance value of 12.8 mF/cm2. Shalini Kulandaivalu, Zulkarnain Zainal, and Yusran Sulaiman Copyright © 2016 Shalini Kulandaivalu et al. All rights reserved. A Photochromic Copolymer Hydrogel Contact Lens: From Synthesis to Application Wed, 19 Oct 2016 07:33:47 +0000 A photochromic poly(2-hydroxyl-ethyl methacrylate-N-vinylpyrrolidone-spironaphthoxazine) hydrogel (p(HEMA-NVP-SPO)) has been designed and synthesized by free radical polymerization in this work. The chemical and structural information of hydrogels was investigated by IR spectra, equilibrium water content (EWC), and SEM. The IR spectra confirmed successful synthesis of copolymer. The domain of NVP contributed to not only EWC but also inner structure of hydrogel, while SPO had little influence on these properties of hydrogel. The photochromic behaviors of hydrogel including photochromic properties and thermal fading kinetics were systematically studied and compared with hydrogel made by immersing method. Results showed that when SPO was incorporated in hydrogel by polymerization, maximum absorbance wavelength got shorter, and the relaxation half-life became longer. In addition, salicylic acid as a drug model could be loaded into hydrogel by immersing method, and its sustained drug release in a given period was dependent on the characteristics of solution and loading time. Xiaoli Yang, Limin Huang, Lihua Zhou, Hao Xu, and Zihan Yi Copyright © 2016 Xiaoli Yang et al. All rights reserved. Polylactic Acid Based Nanocomposites: Promising Safe and Biodegradable Materials in Biomedical Field Tue, 18 Oct 2016 15:51:07 +0000 Polylactic acid (PLA) is widely used in biological areas due to its excellent compatibility, bioabsorbability, and degradation behavior in human bodies. Pure polylactic acid has difficulty in meeting all the requirements that specific field may demand. Therefore, PLA based nanocomposites are extensively investigated over the past few decades. PLA based nanocomposites include PLA based copolymers in nanometer size and nanocomposites with PLA or PLA copolymers as matrix and nanofillers as annexing agent. The small scale effect and surface effect of nanomaterials help improve the properties of PLA and make PLA based nanocomposites more popular compared with pure PLA materials. This review mainly introduces different kinds of PLA based nanocomposites in recent researches that have great potential to be used in biomedical fields including bone substitute and repair, tissue engineering, and drug delivery system. Lili Sha, Zhaofeng Chen, Zhou Chen, Aili Zhang, and Zhaogang Yang Copyright © 2016 Lili Sha et al. All rights reserved. Application of CMC as Thickener on Nanoemulsions Based on Olive Oil: Physical Properties and Stability Tue, 18 Oct 2016 13:43:13 +0000 Carboxymethyl cellulose (CMC) is a hydrocolloid with surface activity that could act as emulsifiers in oil-in-water emulsions; however the principal role is that it acts as structuring, thickening, or gelling agent in the aqueous phase. This study aims to evaluate the application of CMC as thickener into nanoemulsions based on olive oil and their influence on particle characteristics, flow behavior, and color. Four nanoemulsions with different oil (5% and 15% w/w olive oil) and CMC (0.5% and 0.75% w/w) concentration and two control samples without CMC added were prepared using Tween 80 as emulsifier. All physical properties studied on nanoemulsions were depending on both oil and CMC concentration. In general, z-average particle size varied among 107–121 nm and those samples with 5% oil and CMC were the most polydisperse. The addition of CMC increased anionic charge of nanoemulsions obtaining zeta potential values among −41 and −55 mV. The oil concentration increased both consistency and pseudoplasticity of samples, although samples were more stable to gravitational separation at the highest CMC concentration. Color of nanoemulsions was affected principally by the oil concentration. Finally, the results showed that CMC could be applied in nanoemulsions as thickener increasing their physical stability although modifying their physical properties. C. Arancibia, R. Navarro-Lisboa, R. N. Zúñiga, and S. Matiacevich Copyright © 2016 C. Arancibia et al. All rights reserved. Deposition of Ibuprofen Crystals on Hydroxypropyl Cellulose/Polyacrylamide Gel: Experimental and Mathematic Modeling Releasing Tue, 11 Oct 2016 15:01:43 +0000 The crystallization of nonsteroidal anti-inflammatory drug [2-(4-isobutyl-phenyl) propionic acid] ibuprofen (IBP) on a hydroxypropyl cellulose (HPC) and polyacrylamide (PAAm) gel was studied as well as the release kinetics of the drug. The IBP was crystallized on the gel surface of HPC/PAAm. It had a prismatic shape and the growth was made in an aqueous medium; the crystallinity grade of the gels HPC/PAAm and HPC/PAAm-IBU increased to 68% and to 58%, respectively. The release of IBP is performed by two means: by a non-Fickian diffusion process and by relaxation of the chains of the gel; without regard to temperature and the diffusion media, this correlates with the lower critical solution temperature (LCST) of the proposed gel. This polymer matrix provides an option for releasing nonsteroidal anti-inflammatory drugs in a temperature range of 35–39°C. Korsmeyer and Peppas mathematical model was simulated for data releases, statistically significant at 95% confidence level. Claudia Alicia Castillo-Miranda, Ana Beatriz Morales-Cepeda, Carlos Fernando Castro-Guerrero, Homero Salas-Papayanopolos, Hugo Alberto Velasco-Ocejo, Jorge Alberto González-Sánchez, Ulises Paramo-Garcia, and Hugo De Alva-Salazar Copyright © 2016 Claudia Alicia Castillo-Miranda et al. All rights reserved. Effects of Organomontmorillonite Content on Morphology and Mechanical and Thermal Properties of Poly(2,6-dimethyl-1,4-phenylene oxide)/Polyamide-66 Nanocomposites Tue, 11 Oct 2016 13:08:58 +0000 The nanocomposites consisting of polymer matrix and nanofiller have attracted great attention because of the improved physical properties. In this paper, organomontmorillonite (OMMT) was introduced into poly(2,6-dimethyl-1,4-phenylene oxide) grafted maleic anhydride (PPO-g-MA) compatibilized poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide-66 (PPO/PA66) blends by melt extrusion. The morphology of PPO/PA66 nanocomposites with different amounts of OMMT was investigated using transmission electron microscopy (TEM), wide-angle X-ray diffraction (WAXD), and scanning electron microscopy (SEM). The OMMT platelets exhibited an exfoliated structure in the PA66 matrix and an intercalated structure on the surface of PPO domains at low OMMT loading (2 phr). However, the exfoliated platelets in matrix were found to transform into intercalated stacks by adding 6 phr of OMMT. The mechanical properties and thermal stability were significantly improved with the coexistence of exfoliated and intercalated OMMT at low OMMT loading (2–4 phr). The exfoliated OMMT platelets imposed a confinement effect on the macromolecular chains and thereby increased the storage modulus and complex viscosity of nanocomposites. Kunxiao Yang, Chunling Xin, Ying Huang, Lilong Jiang, and Yadong He Copyright © 2016 Kunxiao Yang et al. All rights reserved. Phospholipid Adsorption Polymeric Materials for Detection of Xylazine and Metabolite in Blood and Urine Tue, 11 Oct 2016 12:08:45 +0000 Polymers have been used in different areas. Recently, polymeric material is favored in analytical area due to its high performance and high consistency, which was used in sample pretreatment in this study. Xylazine poisoning is often seen in body fluid samples obtained from various accidents or suicides. However, the content of xylazine is difficult to detect precisely due to matrix effect in testing practices. In this paper, a method application for phospholipid adsorption polymeric materials to determine xylazine in blood and urine samples was proposed, developed, and validated. Compared with existing method, this method using polymeric pretreatment has a wider linear range of 2.0–2000.0 ng/mL for xylazine and its metabolite 2,6-dimethylaniline in both blood and urine and lower detection limits of 0.3 ng/mL for 2,6-dimethylaniline and xylazine in blood and 0.2 ng/mL for 2,6-dimethylaniline and xylazine in urine. Therefore, this method is suggested to be applied in testing practices by academic groups and commercial organizations. Xue Gao, Hao Guo, and Chaokang Gu Copyright © 2016 Xue Gao et al. All rights reserved. Influence of the Initial Fiber Orientation on the Weld Strength in Welding of Glass Fiber Reinforced Thermoplastics Tue, 11 Oct 2016 11:49:35 +0000 The welding factors are significantly lower in welding of fiber reinforced thermoplastics than in welding of unreinforced thermoplastics due to the fiber orientation in the weld. This paper presents results from investigations on the influence of the initial fiber orientation on the weld strength in hot plate and vibration welding for glass fiber reinforced polypropylene and polyamide 6. Injection molded specimens are compared to specimens with main initial fiber orientation being longitudinal and transverse to the joining direction. The results of CT analysis of the fiber orientation in the weld show the opportunity to achieve a higher weld strength by using specimens with fibers being initially oriented longitudinally to the joining direction. The influence of the initial fiber orientation in the parts to be welded on the weld strength in hot plate welding is more distinct than in vibration welding. Isabel Fiebig and Volker Schoeppner Copyright © 2016 Isabel Fiebig and Volker Schoeppner. All rights reserved. Microwave-Assisted Synthesis of Chitosan/Polyvinyl Alcohol Silver Nanoparticles Gel for Wound Dressing Applications Tue, 11 Oct 2016 09:10:44 +0000 The purpose of this study was to fabricate chitosan/poly(vinyl alcohol)/Ag nanoparticles (CPA) gels with microwave-assistance for skin applications. Microwave irradiation was employed to reduce silver ions to silver nanoparticles and to crosslink chitosan (CS) with polyvinyl alcohol (PVA). The presence of silver nanoparticles in CPA gels matrix was examined using UV-Vis spectroscopy, transmission electron microscopy, and X-ray diffraction. The interaction of CS and PVA was analysed by Fourier transform infrared spectroscopy. The release of silver ions was determined by atomic absorption spectrometry. The antimicrobial properties of CPA gels against P. aeruginosa and S. aureus were investigated using agar diffusion method. Finally, the biocompatibility and wound-healing ability of the gels were studied using fibroblast cells (in vitro) and mice models (in vivo). In conclusion, the results showed that CPA gels were successfully fabricated using microwave irradiation method. These gels can be applied to heal an open wound thanks to their antibacterial activity and biocompatibility. Nguyen Thi Hiep, Huynh Chan Khon, Vo Van Thanh Niem, Vo Van Toi, Tran Ngoc Quyen, Nguyen Dai Hai, and Mai Ngoc Tuan Anh Copyright © 2016 Nguyen Thi Hiep et al. All rights reserved. Development of Bioadhesive Microspheres for Oral Bioavailability Enhancement of Berberine Hydrochloride Mon, 10 Oct 2016 14:35:56 +0000 The objective of this study was to innovatively prepare chitosan-coated alginate/gelatin BBH loaded microspheres and evaluate their pharmaceutical characteristics and pharmacokinetics. The bioadhesive microspheres were prepared using an emulsification technique. Three batches of microspheres were formed and their stability was evaluated. BBH loaded microspheres were almost spherical with shallow elevation on surfaces. The mean particle size of microspheres was 368.2 μm, drug loading was %, and in situ bioadhesion percentage was and they achieved a sustained release with 71.29% for 8 hours in vitro. Pharmacokinetic studies in rats indicated that the bioavailability of BBH microspheres was enhanced about 1.5-fold as compared with commercial tablets. BBH microspheres exhibited a sustained-release profile over 48 h. Thus, chitosan-coated alginate/gelatin BBH loaded microspheres which combined the advantages of alginate/gelatin microspheres and chitosan may be used as a sustained delivery system for BBH to treat duodenal and benign gastric ulcers. Ye Zhang and Hongming Liu Copyright © 2016 Ye Zhang and Hongming Liu. All rights reserved. Microstructure and Mechanical Properties of the Butt Joint in High Density Polyethylene Pipe Tue, 04 Oct 2016 07:58:03 +0000 The microstructure and mechanical properties of the butt joint in high density polyethylene (HDPE) pipes were evaluated by preparing the joints with increasing the cooling time from 10 s to 70 s before pressure created for fusion of the pipes. Here, cold fusion flaws in HDPE butt joint were created with increasing the cooling time around 70 s caused by the close molecular contact followed by insufficient interdiffusion of chain segments back and forth across the wetted interface. The tensile failure mechanism of the welded pipes at different fusion time was projected based on the tensile test of dog-bone shaped, fully notched bar type as well as round U-notched specimens. The mechanical properties of the joints at different fusion time were correlated with the corresponding fracture surface morphology. The weld seam as well as tensile fracture surfaces were etched using strong oxidizing agents. The crystallinity of surface etched weld zone by potassium permanganate based etchant was found higher than unetched sample due to the higher susceptibility of amorphous phase of polyethylene with oxidizing agent. The U-notched tensile test of butt welded HDPE pipe and surface etching of the weldments provided clear delineation about the joint quality. Pashupati Pokharel, Yoonsang Kim, and Sunwoong Choi Copyright © 2016 Pashupati Pokharel et al. All rights reserved. Constructing Functional Ionic Membrane Surface by Electrochemically Mediated Atom Transfer Radical Polymerization Thu, 29 Sep 2016 11:34:50 +0000 The sodium polyacrylate (PAANa) contained polyethersulfone membrane that was fabricated by preparation of PES-NH2 via nonsolvent phase separation method, the introduction of bromine groups as active sites by grafting α-Bromoisobutyryl bromide, and surface-initiated electrochemically atom transfer radical polymerization (SI-eATRP) of sodium acrylate (AANa) on the surface of PES membrane. The polymerization could be controlled by reaction condition, such as monomer concentration, electric potential, polymerization time, and modifier concentration. The membrane surface was uniform when the monomer concentration was 0.9 mol/L, the electric potential was −0.12 V, the polymerization time was 8 h, and the modifier concentration was 2 wt.%. The membrane showed excellent hydrophilicity and blood compatibility. The water contact angle decreased from 84° to 68° and activated partial thromboplastin increased from 51 s to 84 s after modification of the membranes. Fen Ran, Dan Li, and Jiayu Wu Copyright © 2016 Fen Ran et al. All rights reserved.