jrups
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Abstract: Substituted triphenylamine cation radical salts having anions of the type SbF6-, PF6-, BF4- and SbCl6-, were prepared and used to initiate cationic polymerization of cyclohexene oxide (CHO), tetrahydrofuran (THF), and N-vinyl carbazole (NVC), thermally in dichloromethane at room temperature. Experimental results are presented to show the effects of salt counter ion, concentration, and polymerization conditions on the yield and the molecular weight of the obtained polymer. THF polymerization was enhanced by photolysis of the reaction mixture for short time. A general mechanism for the polymerization by cation-radical salts of substituted triphenylamine is proposed. Keywords: Tris-(p-bromophenyl) amine. Cation radical salts. Cationic polymerization. N-vinyl carbazole. Cyclohexene oxide. Tetrahydrofuran. |
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Abstract: Development of new alternative materials having the superior characteristics than traditional material has become a new buzz to the researchers. One of the achievements in this field is fibre reinforced polymer composites (FRPCs). The most fascinating aspect of FRPCs is light weight but higher strength and chemical resistance. Further to obtain a biodegradable one natural fibre are taking place of synthetic fibre in the processing of NFRPCs. Researchers have done extensive research works on NFRPCs to expand it application field. But sometimes only natural fibre reinforcement cannot fulfil the design requirement. Hybridization with synthetic fibre reinforcement can significantly improve the physical and mechanical properties despite of processing parameters. Again, nanoparticle fillers are also helpful to enhance the mechanical properties. The aim of this study is to clarify the use of different types of natural fibres as reinforcement to fabricate polymer composites and their corresponding mechanical properties for particular application which will be helpful to design NFRPCs for different application. Keywords: Natural Fibre, Synthetic Fibre, Composites, Biodegradability, Mechanical Properties. |
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Abstract: Major advantage of silane-modified systems is possibility to cross link reactive silanol groups and fortify polymer mechanical and chemical properties. However, application of modern analysis techniques and further characterization of macromolecular structure produced is complicated due to a poor solubility of silane modified polymer in various solvents. Silane modified polyvinyl acetate (PVAc) dispersions were produced by classic radical and RAFT polymerization using silane co-monomers and dispersion system stabilizer - silane modified industrial grade polyvinyl alcohol.The present paper deals with confirmation of silanol, siloxane bonds, silicon content and distribution, as well film surface morphology of silane modified PVAc dispersions films. Keywords: Polyvinyl acetate, RAFT, alkoxysilane, siloxane bonds, element mapping.Download Full Article |
Abstract : Characterization of Phosphate Glass Reinforced Gelatin Blend Bioactive Composite Films
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Abstract: Bioactive composite films were prepared using bioresorbable phosphate glass powder and biodegradable polymer gelatin (G) through solution casting process. Biocompatible monomer, 2-hydroxyethyl methacrylate (HEMA) was used as the cross-linking agent and bioresorbable phosphate glass (PG) powder was used as reinforcement filler. The composite films were obtained at various ratios of G, PG and HEMA. The PG modified gelatin composite (PG/G) film was fabricated at a weight ratio of 12:88 while HEMA modified gelatin composite (HEMA/G) film at 50:50 ratio. On the other hand, hybrid gelatin composite film, containing both PG and HEMA, was obtained using a G/PG/HEMA ratio of 44:12:44. Incorporation of PG improved the mechanical properties of the composite films. Morphological property of the composite films was investigated by stereo microscope and it revealed that the composite films were porous in nature. The thermal behaviour of the films was studied using thermogravimetric analysis. Water uptake of the films was also performed. Keywords: Gelatin, phosphate glass, bioactive, composite films, stereo microscope.Download Full Article |
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Abstract: Stretchable fabrics have gained much interest in the last few years because their higher comforts and aesthetic properties. The main parameters which control the stretchable fabric properties were found to be spandex linear density and draft ratio. In this research paper, the influences of these variables on color properties of stretchable fabrics were investigated. Color properties of the stretchable fabrics were characterized by whiteness index, K/S values, and colorfastness to washing, rubbing and perspiration. The results of this work showed that color properties of the stretchable woven fabrics were affected byindependent variables. Generally, impact of spandex draft ratio on color properties was more pronounced than the effects of spandex linear density. Keywords: Stretchable fabrics, Spandex, Draft ratio, Linear density, Color strength, Whiteness index. |