Journal of Soft Matter http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Burst Diaphragms Based on Carbon Black/Silica Hybrid Filler Reinforced Nitrile Rubber Compounds Tue, 02 Sep 2014 11:05:15 +0000 http://www.hindawi.com/journals/jsmat/2014/498563/ Nitrile rubber (NBR) based elastomer compounds containing different carbon black/silica composition ratios were prepared using laboratory-scale two roll mill. According the cure characterization results, addition of the reinforcing filler, either carbon black or silica, shortened the optimum cure time and also scorch time of samples compared to that of pure NBR gum where the optimum cure time and scorch time both decreased with increasing the silica content of hybrid filler. Analysis of mechanical properties showed that burst strength of carbon black-rich NBR compounds was higher compared to the samples containing silica. This is presumably due to the higher elongation at break observed in NBR/silica compounds revealing lower crosslink density. In fact, adsorption of curing agents onto the functional groups present at the silica surface would be responsible for the lower crosslink density. According to the Barlow’s formula, despite the higher tensile strength of NBR/silica compounds, higher elongation at break leads to the lower burst strength of NBR/silica/carbon black diaphragms. Ali Asghar Davoodi, Tal’at Khalkhali, Mohammad Mahdi Salehi, and Soheil Sarioletlagh Fard Copyright © 2014 Ali Asghar Davoodi et al. All rights reserved. Preparation and Properties of 3D Chitosan Microtubes Tue, 12 Aug 2014 11:35:46 +0000 http://www.hindawi.com/journals/jsmat/2014/863096/ The preparation of 3D chitosan microtubes from polymer solutions in citric and lactic acids by the wet and dry molding methods is described. The mechanism of formation of the insoluble polymeric layer constructing the walls of these microtubes is characterized. The microtubes obtained from chitosan solutions in citric acid are found to have a fragile porous inner layer. For those obtained from chitosan solutions in lactic acid the morphology, elastic-deformation properties, physicomechanical properties, and biocompatibility were assessed. These samples have smooth outer and inner surfaces with no visible defects and high values of elongation at break. The strength of the microtubes obtained by the dry method is much higher than in the case of the wet one. A high adhesion and high proliferative activity of the epithelial-like MA-104 cellular culture on the surface of our microtubular substrates in model in vitro experiments were revealed. Prospects of using chitosan microtubes as vascular prostheses are suggested. Natalia O. Gegel, Anna B. Shipovskaya, Luba S. Vdovykh, and Tatiana S. Babicheva Copyright © 2014 Natalia O. Gegel et al. All rights reserved. Thermal Conductivity of Gel-Grown Barium Oxalate at 326 and 335 K Wed, 24 Jul 2013 12:36:58 +0000 http://www.hindawi.com/journals/jsmat/2013/162428/ Single crystals of barium oxalate have been grown by gel method using agar-agar gel as media of growth at ambient temperature. The grown crystal crystallizes under monoclinic structure. Thermal conductivity of gel-grown barium oxalate crystals as a function of temperature has been studied at 326 and 335 K by using divided bar method. The thermal conductivity of barium oxalate crystal at 326 K was found 3.685 W m−1 K−1 and 3.133 W m−1 K−1 at 335 K. The reduction of thermal conductivity with the rise in temperature may be due to reduction in mean free path of phonons in the solid. Paresh Vasantlal Dalal Copyright © 2013 Paresh Vasantlal Dalal. All rights reserved. Electrical Conduction Mechanism in Solid Polymer Electrolytes: New Concepts to Arrhenius Equation Wed, 24 Jul 2013 09:24:20 +0000 http://www.hindawi.com/journals/jsmat/2013/323868/ Solid polymer electrolytes based on chitosan NaCF3SO3 have been prepared by the solution cast technique. X-ray diffraction shows that the crystalline phase of the pure chitosan membrane has been partially disrupted. The fourier transform infrared (FTIR) results reveal the complexation between the chitosan polymer and the sodium triflate (NaTf) salt. The dielectric constant and DC conductivity follow the same trend with NaTf salt concentration. The increase in dielectric constant at different temperatures indicates an increase in DC conductivity. The ion conduction mechanism follows the Arrhenius behavior. The dependence of DC conductivity on both temperature and dielectric constant () is also demonstrated. Shujahadeen B. Aziz and Zul Hazrin Z. Abidin Copyright © 2013 Shujahadeen B. Aziz and Zul Hazrin Z. Abidin. All rights reserved. An Elastin-Derived Self-Assembling Polypeptide Thu, 13 Jun 2013 14:33:22 +0000 http://www.hindawi.com/journals/jsmat/2013/732157/ Elastin is an extracellular matrix protein responsible for the elastic properties of organs and tissues, the elastic properties being conferred to the protein by the presence of elastic fibers. In the perspective of producing tailor-made biomaterials of potential interest in nanotechnology and biotechnology fields, we report a study on an elastin-derived polypeptide. The choice of the polypeptide sequence encoded by exon 6 of Human Tropoelastin Gene is dictated by the peculiar sequence of the polypeptide. As a matter of fact, analogously to elastin, it is constituted of a hydrophobic region (GLGAFPAVTFPGALVPGG) and of a more hydrophilic region rich of lysine and alanine residues (VADAAAAYKAAKA). The role played by the two different regions in triggering the adoption of beta-turn and beta-sheet conformations is herein discussed and demonstrated to be crucial for the self-aggregation properties of the polypeptide. Antonietta Pepe and Brigida Bochicchio Copyright © 2013 Antonietta Pepe and Brigida Bochicchio. All rights reserved.