International Journal of Polymer Science The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Civil Engineering Applications of Polymer Composites Mon, 01 Feb 2016 06:16:42 +0000 Gonzalo Martínez-Barrera, Osman Gencel, and João M. L. Reis Copyright © 2016 Gonzalo Martínez-Barrera et al. All rights reserved. Haemostatic Response of Polyethylene Terephthalate Treated by Oxygen and Nitrogen Plasma Afterglows Sun, 31 Jan 2016 08:01:03 +0000 Samples of polymer polyethylene terephthalate were coated with heparin and the haemostatic response has been determined by optical imaging of samples after incubation with fresh blood from a healthy donor. Prior to coating the samples were treated by neutral reactive particles of the oxygen or nitrogen plasma flowing afterglow. X-ray photoelectron spectroscopy analysis showed intensive functionalization of the polymer foils upon treatment with afterglows; however, the concentration of sulphur from heparin remained below the detection limit. The optical imaging showed densely distributed blood platelets in highly activated forms on untreated samples, whereas treatment with both afterglows revealed improved hemocompatibility. Best results were obtained for oxygen-functionalized polymer, whereas additional coating with heparin caused moderate loss of hemocompatibility, that was explained by deactivation of surface functional groups upon incubation with heparin. Metod Kolar and Gregor Primc Copyright © 2016 Metod Kolar and Gregor Primc. All rights reserved. Antiepileptic Effects of Lacosamide Loaded Polymers Implanted Subdurally in GAERS Wed, 20 Jan 2016 14:09:54 +0000 The current experiment investigated the ability of coaxial electrospun poly(D,L-lactide-co-glycolide) (PLGA) biodegradable polymer implants loaded with the antiepileptic drugs (AED) lacosamide to reduce seizures following implantation above the motor cortex in the Genetic Absence Epilepsy Rat from Strasbourg (GAERS). In this prospective, randomized, masked experiments, GAERS underwent surgery for implantation of skull electrodes (), skull electrodes and blank polymers (), or skull electrodes and lacosamide loaded polymers (). Thirty-minute electroencephalogram (EEG) recordings were started at day 7 after surgery and continued for eight weeks. The number of SWDs and mean duration of one SWD were compared week-by-week between the three groups. There was no difference in the number of SWDs between any of the groups. However, the mean duration of one SWD was significantly lower in the lacosamide polymer group for up to 7 weeks when compared to the control group (). The mean duration of one seizure was also lower at weeks 3, 5, 6, and 7 when compared to the blank polymer group ( = 0.016, 0.037, 0.025, and 0.025, resp.). We have demonstrated that AED loaded PLGA polymer sheets implanted on the surface of the cortex could affect seizure activity in GAERS for a sustained period. Sebastien H. Bauquier, Jonathan L. Jiang, Zhilian Yue, Alan Lai, Yu Chen, Simon E. Moulton, Karen J. McLean, Sara Vogrin, Amy J. Halliday, Gordon Wallace, and Mark J. Cook Copyright © 2016 Sebastien H. Bauquier et al. All rights reserved. Time Dependent Influence of Rotating Magnetic Field on Bacterial Cellulose Mon, 18 Jan 2016 11:50:31 +0000 The aim of the study was to assess the influence of rotating magnetic field (RMF) on the morphology, physicochemical properties, and the water holding capacity of bacterial cellulose (BC) synthetized by Gluconacetobacter xylinus. The cultures of G. xylinus were exposed to RMF of frequency that equals 50 Hz and magnetic induction 34 mT for 3, 5, and 7 days during cultivation at 28°C in the customized RMF exposure system. It was revealed that BC exposed for 3 days to RMF exhibited the highest water retention capacity as compared to the samples exposed for 5 and 7 days. The observation was confirmed for both the control and RMF exposed BC. It was proved that the BC exposed samples showed up to 26% higher water retention capacity as compared to the control samples. These samples also required the highest temperature to release the water molecules. Such findings agreed with the observation via SEM examination which revealed that the structure of BC synthesized for 7 days was more compacted than the sample exposed to RMF for 3 days. Furthermore, the analysis of 2D correlation of Fourier transform infrared spectra demonstrated the impact of RMF exposure on the dynamics of BC microfibers crystallinity formation. Karol Fijałkowski, Rafał Rakoczy, Anna Żywicka, Radosław Drozd, Beata Zielińska, Karolina Wenelska, Krzysztof Cendrowski, Dorota Peitler, Marian Kordas, Maciej Konopacki, and Ewa Mijowska Copyright © 2016 Karol Fijałkowski et al. All rights reserved. Effect of Cultivation Time and Medium Condition in Production of Bacterial Cellulose Nanofiber for Urease Immobilization Thu, 31 Dec 2015 14:03:12 +0000 A new nanoporous biomatrix originated from bacterial resources has been chosen for urease immobilization. Urease has been immobilized on synthesized bacterial cellulose nanofiber since this enzyme has a key role in nitrogen metabolism. Gluconacetobacter xylinum ATCC 10245 has been cultivated for synthesis of a nanofiber with the diameter of 30–70 nm. Different cultivation processes in the aspect of time and cultivation medium conditions were chosen to study the performance of immobilized enzyme on four types of bacterial cellulose nanofibers (BCNs). Urease immobilization into the nanofiber has been done in two steps: enzyme adsorption and glutaraldehyde cross-linking. The results showed that the immobilized enzymes were relatively active and highly stable compared to the control samples of free enzymes. Optimum pH was obtained 6.5 and 7 for different synthesized BCNs, while the optimum temperature for immobilized urease was 50°C. Finding of the current experiment illustrated that the immobilized enzyme in optimum condition lost its initial activity by 41% after 15 weeks. M. Pesaran, Gh. Amoabediny, and F. Yazdian Copyright © 2015 M. Pesaran et al. All rights reserved. Role of Nonmonotonic Constitutive Curves in Extrusion Instabilities Wed, 30 Dec 2015 08:11:33 +0000 Flow instabilities of non-Newtonian fluids severely hamper the quality of products during various chemical processes, such as fibre spinning, extrusion, and film blowing. The origin of extrusion instability has been studied over many decades. However, no consensus has been reached among the research community so far. In this paper, the possible cause of extrusion instabilities is explored using the finitely extensible nonlinear elastic conformation-dependent (FENE-CD) model with a nonmonotonic constitutive curve. Many well-documented experimental phenomena are reproduced in our simulations, and it could be concluded that the nonmonotonic constitutive curve plays an essential role in extrusion instabilities. In addition, the results imply that the die exit singularity may generate or magnify oscillations. Yu Cao, Wen-Jing Yang, Xiao-Wei Guo, Xin-Hai Xu, Juan Chen, Xue-Jun Yang, and Xue-Feng Yuan Copyright © 2015 Yu Cao et al. All rights reserved. Physical, Mechanical, and Thermal Analysis of Polylactic Acid/Fumed Silica/Clay (1.28E) Nanocomposites Tue, 29 Dec 2015 12:34:39 +0000 Polylactic acid/fumed silica/clay (PLA/FS/clay) (1.28E) nanocomposites have been successfully prepared by solution-intercalation film-casting technique. The resultant nanocomposites were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), tensile test, thermogravimetric analysis (TGA), and moisture absorption test. The FT-IR spectrum indicated that PLA/FS/clay with 2 wt% had much broader peak compared to 5 wt%, 10 wt%, and 15 wt% nanocomposites. Incorporation of clay (1.28E) with 2 wt% showed the best compatibility with PLA/FS matrix. PLA/FS/clay (1.28E) nanocomposite with 2 wt% of clay loading had higher tensile strength and modulus compared to other nanocomposites. The thermal stability and activation energy of 2 wt% of PLA/FS/clay (1.28E) nanocomposite are the highest among all the nanocomposites. The moisture absorbed into PLA/FS/clay (1.28E) nanocomposite was significantly reduced with clay loading of 2 wt%. Josephine Chang Hui Lai, Md. Rezaur Rahman, and Sinin Hamdan Copyright © 2015 Josephine Chang Hui Lai et al. All rights reserved. Thermal Analysis of NR Composite with MWCNTs Aligned in a Magnetic Field Thu, 24 Dec 2015 07:52:06 +0000 We got the aligned carbon tube in the rubber matrix through magnetic field. TEM shows that Fe3O4 is symmetrically coated on the outer surface of MWCNTs. Diffraction peaks corresponding to Fe3O4 cubic crystal also appeared in the X-ray diffraction spectra. Thermal conductivity of composites increases by filling the appropriate content of carbon tube. If the magnetic field is larger and the direction time is longer, a greater thermal conductivity of composites can be obtained. Jin Xu and Yan He Copyright © 2015 Jin Xu and Yan He. All rights reserved. A Facile Approach to Evaluate Thermal Insulation Performance of Paper Cups Tue, 22 Dec 2015 14:24:50 +0000 Paper cups are ubiquitous in daily life for serving water, soup, coffee, tea, and milk due to their convenience, biodegradability, recyclability, and sustainability. The thermal insulation performance of paper cups is of significance because they are used to supply hot food or drinks. Using an effective thermal conductivity to accurately evaluate the thermal insulation performance of paper cups is complex due to the inclusion of complicated components and a multilayer structure. Moreover, an effective thermal conductivity is unsuitable for evaluating thermal insulation performance of paper cups in the case of fluctuating temperature. In this work, we propose a facile approach to precisely analyze the thermal insulation performance of paper cups in a particular range of temperature by using an evaluation model based on the MISO (Multiple-Input Single-Output) technical theory, which includes a characterization parameter (temperature factor) and a measurement apparatus. A series of experiments was conducted according to this evaluation model, and the results show that this evaluation model enables accurate characterization of the thermal insulation performance of paper cups and provides an efficient theoretical basis for selecting paper materials for paper cups. Yudi Kuang, Gang Chen, and Zhiqiang Fang Copyright © 2015 Yudi Kuang et al. All rights reserved. Salmon Muscle Adherence to Polymer Coatings and Determination of Antibiotic Residues by Reversed-Phase High-Performance Liquid Chromatography Coupled to Selected Reaction Monitoring Mass Spectrometry, Atomic Force Microscopy, and Fourier Transform Infrared Spectroscopy Tue, 22 Dec 2015 14:12:23 +0000 The persistent adhesion of salmon muscle to food container walls after treatment with urea solution was observed. This work evaluated the diffusion of antibiotics from the salmon muscle to the polyethylene terephthalate (PET) coating protecting the electrolytic chromium coated steel (ECCS) plates. New aquaculture production systems employ antibiotics such as florfenicol, florfenicol amine, oxytetracycline, and erythromycin to control diseases. The introduction of antibiotics is a matter of concern regarding the effects on human health and biodiversity. It is important to determine their impact on the adhesion of postmortem salmon muscle to can walls and the surface and structural changes affecting the functionality of multilayers. This work characterized the changes occurring in the multilayer PET polymer and steel of containers by electron microscopy, 3D atomic force microscopy (3D-AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. A robust mass spectrometry methodology was employed to determine the presence of antibiotic residues. No evidence of antibiotics was observed on the protective coating in the range between 0.001 and 2.0 ng/mL; however, the presence of proteins, cholesterol, and alpha-carotene was detected. This in-depth profiling of the matrix-level elements is relevant for the use of adequate materials in the canning export industry. E. Zumelzu, M. J. Wehrhahn, O. Muñoz, and F. Rull Copyright © 2015 E. Zumelzu et al. All rights reserved. Controlling the Melt Resistance to Flow as a Possibility of Improving the Miscibility and the Time Behavior of Some Blends Based on Starch Mon, 21 Dec 2015 13:52:56 +0000 The paper proves that the miscibility of some blends based on starch can be improved by finding for each of them the melt resistance to flow at which the nonstationary flow and the melt degradation are avoided and the developed shear rate homogenizes optimally the material composition. The obtained results show that, for process sensitive materials like starches, the border between good and less miscibility is so narrow that the window of melt processing conditions and the best formulation must be found for each of them. The improving of miscibility by controlling the melt resistance to flow proves to be a good method to prevent retrogradation and plasticizer leaching and so to handle the new compounds behavior during usage. Doina Dimonie, Miruna Musat, Sanda Maria Doncea, Celina Maria Damian, Liliana Anton, Eugeniu Vasile, Roxana Trusca, and Maria Râpă Copyright © 2015 Doina Dimonie et al. All rights reserved. Mechanical Characterization and Water Absorption Behaviour of Interwoven Kenaf/PET Fibre Reinforced Epoxy Hybrid Composite Sun, 20 Dec 2015 16:08:27 +0000 The development of interwoven fabric for composite production is a novel approach that can be adopted to address the challenges of balanced mechanical properties and water absorption behaviour of polymer composites. In this paper, kenaf and PET (polyethylene terephthalate) fibre were selected as reinforcing materials to develop the woven fabric, and low viscosity epoxy resin was chosen as the matrix. Vacuum infusion process was adopted to produce the hybrid composite due to its superior advantages over hand lay-up technique. The weight percentage composition of the Epoxy/kenaf/PET hybrid composite was maintained at 70/15/15 and 60/20/20, respectively. A significant increase in tensile strength and elastic modulus of approximately 73% and 53% was recorded in relation to neat epoxy. Similarly, a substantial increase in flexural, impact, and interlaminar properties was also realized in relation to neat epoxy. This enhancement in mechanical properties may be attributed to the interlocking structure of the interwoven fabric, individual properties of kenaf and PET fibres, strong interfacial bonding, and resistance of the fibres to impact loading. The water absorption of the composites was studied by prolonged exposure in distilled water, and the moisture absorption pattern was found to follow Fickian behaviour. Yakubu Dan-mallam, Tan Wei Hong, and Mohd Shukry Abdul Majid Copyright © 2015 Yakubu Dan-mallam et al. All rights reserved. Synthesis and Characterization of New Thiolated Chitosan Nanoparticles Obtained by Ionic Gelation Method Tue, 15 Dec 2015 08:57:12 +0000 We derivatized low molecular weight chitosan (LMWC) with 3-mercaptopropanoic acid (3-MPA) by a coupling reaction. The chemical modification of LMWC was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance, 1HNMR. We researched the influence of 3-MPA on the nanoparticles formation by ionic gelation method using sodium tripolyphosphate (TPP) as cross-linker reagent. In order to optimize the nanoparticles formation, we studied the effect of the pH solution and molar ratio on nanoparticles stability. Analyses of particle size, morphology, and surface charge were determined by dynamic light scattering, Atomic Force Microscopy, and zeta potential, respectively. It was found that formation of semispherical and stable nanoparticles was improved due to the chemical modification of chitosan. Optimized semispherical nanoparticles of thiolated chitosan were synthesized with the parameters (pH 4.7, molar ratios 1 : 106). Additionally, we reported the thermodynamic profile of the nanoparticles formation determined by isothermal titration calorimetry (ITC). The aggregation process achieved to form nanoparticles of thiolated and nonmodified chitosan consisted of two stages, considering one binding site model. Gibbs free energy and binding constant () describe the aggregation process of thiolated chitosan/TPP, which is an initial reaction and followed by an endothermic stage. These results are promising for the possible application of these nanoparticles as nanocarriers and delivery systems. Reynaldo Esquivel, Josué Juárez, Mario Almada, Jaime Ibarra, and Miguel A. Valdez Copyright © 2015 Reynaldo Esquivel et al. All rights reserved. Designing of Collagen Based Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Scaffolds for Tissue Engineering Tue, 15 Dec 2015 07:52:09 +0000 P(3HB-co-4HB) copolymer was modified using collagen by adapting dual solvent system. The surface properties of samples were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), organic elemental analysis (CHN analysis), and water contact angle measurements. The effects of collagen concentration, scaffold thickness, and 4HB molar fraction on the hydrophilicity were optimized by the Taguchi method. The orthogonal array experiment was conducted to obtain the response for a hydrophilic scaffold. Analysis of variance (ANOVA) was used to determine the significant parameters and determine the optimal level for each parameter. The results also showed that the hydrophilicity of P(3HB-co-4HB)/collagen blend scaffolds increased as the collagen concentration increased up to 15 wt% with a molar fraction of 50 mol% at 0.1 mm scaffold thickness. The biocompatibility of the P(3HB-co-4HB)/collagen blend surface was evaluated by fibroblast cell (L929) culture. The collagen blend scaffold surfaces showed significant cell adhesion and growth as compared to P(3HB-co-4HB) copolymer scaffolds. S. Vigneswari, H. P. S. Abdul Khalil, and A. A. Amirul Copyright © 2015 S. Vigneswari et al. All rights reserved. Membrane Made of Cellulose Acetate with Polyacrylic Acid Reinforced with Carbon Nanotubes and Its Applicability for Chromium Removal Tue, 08 Dec 2015 07:02:26 +0000 Membranes made of carbon nanotubes and cellulose acetate with polyacrylic acid were designed in order to study their properties and their applicability for chromium removal. The membranes were prepared by phase inversion method using cellulose acetate and polyacrylic acid. Carbon nanotubes were added to the membrane during their process of synthesis in proportions of 1% by weight. The pores in the material are formed in layers, giving the effect of depth and forming a network. Both the carbon nanotubes and membranes were characterized by IR, Raman, and SEM spectroscopy. In addition, the concentration of acidic and basic sites and the surface charge in the materials were determined. The concentration of acid sites for oxidized nanotubes was 4.0 meq/g. The removal of Cr(VI) was studied as a function of contact time and of initial concentration of Cr(VI). The removal of Cr(VI) (~90%) mainly occurs in a contact time from 32 to 64 h when the initial concentration of Cr(VI) is 1 mg/L. J. A. Sánchez-Márquez, R. Fuentes-Ramírez, I. Cano-Rodríguez, Z. Gamiño-Arroyo, E. Rubio-Rosas, J. M. Kenny, and N. Rescignano Copyright © 2015 J. A. Sánchez-Márquez et al. All rights reserved. Environmental Impacts on the Strength Parameters of Mineral-Acrylic (PMMA/ATH) Facade Panels Thu, 03 Dec 2015 13:46:44 +0000 Composite mineral-acrylic panels consist in 80% of natural minerals produced from bauxite (aluminium hydroxides (ATH)) and in 20% from acrylic resin (polymethyl methacrylate (PMMA)). This material due to high usability is widely used in interior finishes. Recently, the mineral-acrylic panels have been used as external claddings of buildings. So far, there are several dozen elevations realized worldwide. Due to the variability of the strength parameters of PMMA acrylic resins depending on the environmental influence, a number of tests on samples of mineral-acrylic panels to verify their suitability for use in climate conditions in Central Europe were performed. The studies determined the change of the material parameters after being subjected to aging process in conditions of high temperature, high relative humidity, freeze-thaw cycles, and UV radiation. In the studies parameters such as flexural strength and modulus of elasticity were measured at a reference temperature of 23°C. In raised and lowered temperatures only the tensile strength tests were conducted. Due to the lack of information in the available literature, the authors carried out tests of the temperature influence on the PMMA/ATH composite modulus of elasticity and flexural strength which is crucial in designing process. Aleksander Byrdy and Michał Kołaczkowski Copyright © 2015 Aleksander Byrdy and Michał Kołaczkowski. All rights reserved. Conditions to Prolonged Release of Microencapsulated Carvacrol on Alginate Films as Affected by Emulsifier Type and PH Thu, 03 Dec 2015 07:59:46 +0000 Alginate from algal biomass is used as edible film and the incorporation of antimicrobial agents improves its performance to increase the shelf-life of fresh foods. However, environmental conditions and intrinsic properties of films influence their release. The aim of this study was to investigate the effect of the concentration and type of encapsulating agent and pH of emulsions on the physical and antimicrobial properties of alginate-carvacrol films. Films containing alginate, carvacrol as antimicrobial agent, and Tween 20 or trehalose (0.25 and 0.75% w/w) as encapsulating agents were obtained from suspensions at pH 4 and pH 8. Physical characterization of emulsions and films and antimicrobial properties (E. coli and B. cinerea) was evaluated. Results showed that droplets size depended on trehalose concentration, but emulsion stability depended on pH and type of encapsulating agent, being more stable samples with trehalose at pH 4. Although films with Tween 20 presented the highest opacity, they showed the best antimicrobial properties at initial time; however, during storage time, they lost their activity before samples with trehalose and relative humidity (RH) was the principal factor to influence their release. Therefore, sample formulated with 0.25% trehalose at pH 4 and stored at 75% RH had the best potential as edible film for fresh fruits. Silvia Matiacevich, Natalia Riquelme, and María Lidia Herrera Copyright © 2015 Silvia Matiacevich et al. All rights reserved. Dynamics Analysis of the Melt Conveying Process in a Novel Extruder Tue, 01 Dec 2015 08:21:34 +0000 This study investigates dynamics of the melt conveying process in a novel extruder in which a polymer experiences a primarily elongational deformation field. The working principle of the novel extruder is completely different from that of conventional screw extruders. At the last stage of polymer processing in the proposed novel extruder, melt is conveyed through feeding and discharging processes. Here we present a mathematical model to analyze dynamics in the melt conveying process. Melt extrusion is primarily influenced by the position of vane chamber and the structural parameters of the novel extruder such as eccentricity. Zan Huang Copyright © 2015 Zan Huang. All rights reserved. Application of Microbial Biopolymers as an Alternative Construction Binder for Earth Buildings in Underdeveloped Countries Sun, 29 Nov 2015 13:31:45 +0000 Earth buildings are still a common type of residence for one-third of the world’s population. However, these buildings are not durable or resistant against earthquakes and floods, and this amplifies their potential harm to humans. Earthen construction without soil binders (e.g., cement) is known to result in poor strength and durability performance of earth buildings. Failure to use construction binders is related to the imbalance in binder prices in different countries. In particular, the price of cement in Africa, Middle East, and Southwest Asia countries is extremely high relative to the global trend of consumer goods and accounts for the limited usage of cement in those regions. Moreover, environmental concerns regarding cement usage have recently risen due to high CO2 emissions. Meanwhile, biopolymers have been introduced as an alternative binder for soil strengthening. Previous studies and feasibility attempts in this area show that the mechanical properties (i.e., compressive strength) of biopolymer mixed soil blocks (i.e, both 1% xanthan gum and 1% gellan gum) satisfied the international criteria for binders used in earthen structures. Economic and market analyses have demonstrated that the biopolymer binder has high potential as a self-sufficient local construction binder for earth buildings where the usage of ordinary cement is restricted. Ilhan Chang, Minkyung Jeon, and Gye-Chun Cho Copyright © 2015 Ilhan Chang et al. All rights reserved. Optimized Monitoring of Production of Cellulose Nanowhiskers from Opuntia ficus-indica (Nopal Cactus) Thu, 26 Nov 2015 09:34:21 +0000 Preparation of cellulose nanowhiskers (CNWs) has grown significantly because they are useful for a wide range of applications. Additional advantage in their design requires that they meet the following characteristics: nontoxicity, abundance, sustainability, renewability, and low cost. To address these requirements, nanowhiskers were prepared from Opuntia ficus-indica (nopal) cellulose by acid hydrolysis. Monitoring the process of CNWs preparation is necessary to ensure maximum yield and purity of the end product. In this study, the cellulose preparation was monitored by analyzing microscopic morphology by SEM; the purity degree was determined by fluorescence microscopy as a novel and rapid technique, and FTIR spectroscopy was used for confirmation. The additional parameters that monitored the process were the crystallinity index by X-ray diffraction and the size of the particle by dynamic light scattering (DLS). Nopal cellulose was found to be comparable to commercial microcrystalline cellulose. The use of Opuntia ficus-indica is a viable alternative for the production of highly pure CNWs and the strategy to supervise the preparation process was rapid. Horacio Vieyra, Ulises Figueroa-López, Andrea Guevara-Morales, Berenice Vergara-Porras, Eduardo San Martín-Martínez, and Miguel Ángel Aguilar-Mendez Copyright © 2015 Horacio Vieyra et al. All rights reserved. Microbial Cellulose Production from Bacteria Isolated from Rotten Fruit Mon, 23 Nov 2015 16:32:20 +0000 Microbial cellulose, an exopolysaccharide produced by bacteria, has unique structural and mechanical properties and is highly pure compared to plant cellulose. Present study represents isolation, identification, and screening of cellulose producing bacteria and further process optimization. Isolation of thirty cellulose producers was carried out from natural sources like rotten fruits and rotten vegetables. The bacterial isolates obtained from rotten pomegranate, rotten sweet potato, and rotten potato were identified as Gluconacetobacter sp. RV28, Enterobacter sp. RV11, and Pseudomonas sp. RV14 through morphological and biochemical analysis. Optimization studies were conducted for process parameters like inoculum density, temperature, pH, agitation, and carbon and nitrogen sources using Gluconacetobacter sp. RV28. The strain produced 4.7 g/L of cellulose at optimum growth conditions of temperature (30°C), pH (6.0), sucrose (2%), peptone (0.5%), and inoculum density (5%). Characterization of microbial cellulose was done by scanning electron microscopy (SEM). B. E. Rangaswamy, K. P. Vanitha, and Basavaraj S. Hungund Copyright © 2015 B. E. Rangaswamy et al. All rights reserved. Shrinkage Behaviour of Fibre Reinforced Concrete with Recycled Tyre Polymer Fibres Mon, 16 Nov 2015 10:44:59 +0000 Different types of fibres are often used in concrete to prevent microcracking due to shrinkage, and polypropylene fibres are among the most often used ones. If not prevented, microcracks can lead to the development of larger cracks as drying shrinkage occurs, enabling penetration of aggressive substances from the environment and reducing durability of concrete structures. The hypothesis of the present research is that polypropylene fibres, used in concrete for controlling formation of microcracks due to shrinkage, can be replaced with recycled polymer fibres obtained from end-of-life tyres. To test the hypothesis, concrete mixtures containing polypropylene fibres and recycled tyre polymer fibres were prepared and tested. Experimental programme focused on autogenous, free, and restrained shrinkage. It was shown that PP fibres can be substituted with higher amount of recycled tyre polymer fibres obtaining concrete with similar shrinkage behaviour. The results indicate promising possibilities of using recycled tyre polymer fibres in concrete products. At the same time, such applications would contribute to solving the problem of waste tyre disposal. Marijana Serdar, Ana Baričević, Marija Jelčić Rukavina, Martina Pezer, Dubravka Bjegović, and Nina Štirmer Copyright © 2015 Marijana Serdar et al. All rights reserved. Direct Synthesis of Hyperbranched Poly(acrylic acid-co-3-hydroxypropionate) Thu, 12 Nov 2015 11:18:48 +0000 Hyperbranched poly(acrylic acid-co-3-hydroxypropionate) (PAcHP) was synthesized by base-catalyzed hydrogen transfer polymerization of acrylic acid through one step. The copolymers obtained through solution and bulk polymerization were insoluble in water and all organic solvents tried. Structural and compositional characterizations of hyperbranched PAcHP were performed by using FTIR, solid 13C-NMR, TGA, and titrimetric analysis. Acrylate fraction of the hyperbranched PAcHP obtained via bulk polymerization was determined as 60–65% by comparing TGA curves of hyperbranched PAcHP and pure poly(3-hydroxy propionate) (PHP). However, analytical titration of the same sample revealed that acrylic acid units were about 47.3%. The results obtained from TGA and analytical titration were used to evaluate the chemical structure of the copolymer. Hyperbranched PAcHP exhibited hydrogel properties. Swelling behavior of the copolymer was investigated at a wide pH range and ionic strength. The dynamic swelling profiles of hyperbranched PAcHP exhibited a fast swelling behavior in the first hour and achieved the equilibrium state within 12 h in PBS. Depending on the conditions, the copolymers exhibited swelling ratios up to 2100%. As the copolymer has easily biodegradable propionate and versatile functional acrylic acid units, it can be used as not only biodegradable material in medical applications but also raw material in personal care commodities. Efkan Çatıker and Tahsin Filik Copyright © 2015 Efkan Çatıker and Tahsin Filik. All rights reserved. Food Polymers Functionality and Applications Wed, 11 Nov 2015 07:08:57 +0000 Xingxun Liu, Fengwei Xie, Xiaoxi Li, Sumei Zhou, and Liyan Chen Copyright © 2015 Xingxun Liu et al. All rights reserved. Feasibility of Using High-Performance Steel Fibre Reinforced Concrete for Simplifying Reinforcement Details of Critical Members Mon, 09 Nov 2015 16:06:04 +0000 This paper addresses the effects of hooked-end steel fibre contents on the mechanical properties of high-performance concrete (HPC) and investigates the feasibility of utilizing steel fibres to simplify the complicated reinforcement detailing of critical HPC members under high shear stress. Mechanical properties of HPCs with specified compressive strength of 60 and 100 MPa include the flow, air content, compressive strength, and flexural strength. The effectiveness of 1.50% steel fibre content on the shear behaviour of diagonally reinforced concrete coupling beam without additional transverse reinforcement was investigated to alleviate complex reinforcing details for the full section confinement of diagonal bar groups. The test results revealed the incorporation of steel fibres significantly affected the mechanical properties of the HPCs. For diagonally reinforced coupling beam (SFRCCB) without additional transverse reinforcement, the addition of 1.5% steel fibre content into 60 MPa HPC coupling beam provides similar cracking and structural behaviours compared to those of diagonally reinforced coupling beam (CCB) with full section confinement details. However, the ductility of SFRCCB was less than that of CCB. It is recommended that both stirrups and steel fibre should be used for fully confining the diagonal bar groups of coupling beams to achieve the ductile behaviour. Seok-Joon Jang, Dae-Hyun Kang, Kyung-Lim Ahn, Wan-Shin Park, Sun-Woong Kim, and Hyun-Do Yun Copyright © 2015 Seok-Joon Jang et al. All rights reserved. Simulation and Experimental Validation of the Hot Embossing Process of Poly(lactic-co-glycolic acid) Microstructures Sun, 08 Nov 2015 08:29:49 +0000 The microstructures were fabricated by hot embossing method using biodegradable material PLGA poly(lactic-co-glycolic acid), to serve as the drug carriers in the drug delivery system. The embossing process was studied in a combination of simulations and experiments. Firstly, the viscoelastic model of PLGA was built after testing the material properties. Secondly, the hot embossing process was simulated by ABAQUS finite element software. The deformation rules of PLGA during hot embossing were then achieved. The pressures inside the PLGA materials were different at various places during hot embossing, which lead to the differences of the filling speeds. As a result, the inner structures were easier to get formed than the outer structures. And the fluidity of PGLA would increase with the raising temperature, which however caused serious material overflow. Finally the hot embossing experiments were presented to verify the simulation results. Agreed with the filling rules of the simulation, enough duration was necessary to let the outer corners of the microstructures be formed completely. Moreover the trapped air in the grooves was compressed into small bubbles at the corners. It was also found that the material overflow could be prevented in the use of nonisothermal hot embossing method. Xiaopeng Wang, Wei Li, and Tianning Chen Copyright © 2015 Xiaopeng Wang et al. All rights reserved. Experiment Research on Bonding Effect of Poly(lactic-co-glycolic acid) Device by Surface Treatment Method Mon, 02 Nov 2015 07:35:28 +0000 According to the low temperature and high effective bonding problem of microdevices made of degradable polymer PLGA, chemical, plasma, and UV irradiation method are used to study the experimental surface treatment of PLGA films and microdevices bonding process. The results show that all three methods can reduce the surface contact angle of PLGA films, the contact angle increases with time at room temperature, and the PLGA films contact angle is almost unchanged under refrigeration. The PLGA film bonding temperature is significantly reduced after UV irradiation, and the bonding interfaces also generate diffusion cross linking layer are dense and uniform. Xiaopeng Wang, Kun Lian, and Tianning Chen Copyright © 2015 Xiaopeng Wang et al. All rights reserved. Two-Dimensional FTIR as a Tool to Study the Chemical Interactions within Cellulose-Ionic Liquid Solutions Sun, 01 Nov 2015 14:22:37 +0000 In this study two-dimensional FTIR analysis was applied to understand the temperature effects on processing cellulose solutions in imidazolium-based ionic liquids. Analysis of the imidazolium ion νC2–H peak revealed hydrogen bonding within cellulose solutions to be dynamic on heating and cooling. The extent of hydrogen bonding was stronger on heating, consistent with greater ion mobility at higher temperature when the ionic liquid network structure is broken. At ambient temperatures a blue shifted νC2–H peak was indicative of greater cation-anion interactions, consistent with the ionic liquid network structure. Both cellulose and water further impact the extent of hydrogen bonding in these solutions. The FTIR spectral changes appeared gradual with temperature and contrast shear induced rheology changes which were observed on heating above 70°C and cooling below 40°C. The influence of cellulose on solution viscosity was not distinguished on initial heating as the ionic liquid network structure dominates rheology behaviour. On cooling, the quantity of cellulose has a greater influence on solution rheology. Outcomes suggest processing cellulose in ionic liquids above 40°C and to reduce the impacts of cation-anion effects and enhance solubilisation, processing should be done at 70°C. Kalyani Kathirgamanathan, Warren J. Grigsby, Jafar Al-Hakkak, and Neil R. Edmonds Copyright © 2015 Kalyani Kathirgamanathan et al. All rights reserved. Prediction of Mold Spoilage for Soy/Polyethylene Composite Fibers Sun, 01 Nov 2015 09:11:08 +0000 Mold spoilage was determined over 109 days on soy/PE fibers held under controlled temperatures (T) ranging from 10°C to 40°C and water activities from 0.11 to 0.98. Water activities were created in sealed containers using saturated salt solutions and placed in temperature-controlled incubators. Soy/PE fibers that were held at 0.823 or higher exhibited mold growth at all temperatures. As postulated, increased water activity (greater than 0.89) and temperature (higher than 25°C) accelerated mold growth on soy/PE fibers. A slower mold growth was observed on soy/PE fibers that were held at 0.87 and 10°C. A Weibull model was employed to fit the observed logarithmic values of , and an interaction term and was chosen as the final model as it gave the best fit to the raw mold growth data. These growth models predict the expected mold-free storage period of soy/PE fibers when exposed to various environmental temperatures and humidities. Chinmay Naphade, Inyee Han, Sam Lukubira, Amod Ogale, James Rieck, and Paul Dawson Copyright © 2015 Chinmay Naphade et al. All rights reserved. Preparation and Bioactivity Properties of a Novel Composite Membrane of Fructose Mediated β-Tricalcium Pyrophosphate/(Polyethylene Glycol/Chitosan) for Guided Tissue Regeneration Sun, 01 Nov 2015 09:05:01 +0000 A novel composite membrane of β-tricalcium pyrophosphate (β-TCP) and fructose- (F-) mediated chitosan/poly(ethylene glycol) (CS/PEG) was prepared by thermally induced phase separation technique. The prepared composite membranes were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanical property, swelling, degradation, and cytotoxicity of the composite membranes were evaluated in vitro with respect to its potential for use as biodegradable guided tissue regeneration (GTR) membrane. In vitro degradation tests showed the composite membrane with a controllable degradation rate when changing the β-TCP content. The incorporation of β-TCP granules also caused a significant enhancement of tensile strength. When β-TCP content is controlled to 50 wt%, homogeneous composite membranes with well mechanical property and enzymatic degradation rate can be obtained. Cytotoxicity assay demonstrates that the composite membranes were nontoxic and had very good cell compatibility. Most importantly, the release of calcium ions and glucosamine from the composite membranes was proved to increase the cell proliferation of NIH3T3. The results of this study have indicated that this novel F-β-TCP/CS/PEG composite can be a suitable material for GTR applications. Jian-Wen Wang, Min-Hsiung Hon, Yi-Ming Kuo, and Mei-Hui Chung Copyright © 2015 Jian-Wen Wang et al. All rights reserved.