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31.
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The state of water in water-swollen poly(vinyl alcohol-co-itaconic acid) membranes, having various water contents from 0.31 to 0.83, was investigated by d.s.c. measurements and compared with those in water-swollen poly(vinyl alcohol) membranes. The amount of freezing water in the membranes was estimated by use of a relationship between the phase transition temperature and the enthalpy of the crystallization of supercooled water. The melting temperature of the water in the membranes immersed in urea and NaCl 0–2 mol l?1 aqueous solutions was also determined by d.s.c. analysis. The present study proposes a method for estimating the solubilities of urea and NaCl in both of the freezing and the non-freezing water using the melting point depression of the freezing water in the membranes immersed in the solute solution. 相似文献
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The flame‐retardant and smoke‐suppressant properties of inorganic tin compounds such as zinc hydroxystannate (ZHS) and zinc stannate (ZS) were investigated in a comparison with alumina trihydrate, magnesium hydroxide, and Sb2O3 through the limiting oxygen index test and smoke density test. The flame‐retardant mechanisms were studied through the char yield test, SEM, quantitative analysis, thermogravimetry and differential thermal analysis. The thermal degradation in air of flexible PVC treated with the above compounds was studied by thermal analysis from ambient temperature to 800°C. The results showed that tin compounds such as ZHS and ZS could be used as a highly effective flame retardant for flexible PVC, and it appears that the tin compound may exert its action in both the condensed and vapor phases, but mainly in condensed phases as a Lewis acid. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1469–1475, 2005 相似文献
36.
Ying Quan Mingshan Yang Tongxiang Liang Qin Yan Deshan Liu Riguang Jin 《应用聚合物科学杂志》2007,103(6):3940-3949
Novel composite particles based on nanoscale calcium carbonate (nano‐CaCO3) as the core and polyacrylates as the shell were first synthesized by in situ encapsulating emulsion polymerization in the presence of the fresh slush pulp of calcium carbonate (CaCO3) nanoparticles. Subsequently, these modified nanoparticles were compounded with rigid poly(vinyl chloride) (RPVC) to prepare RPVC/CaCO3 nanocomposites. At the same time, the effects of the reinforcement and toughening of these modified nanoparticles on RPVC were investigated, and the synergistic effect of modified nanoparticles with chlorinated polyethylene (CPE) was also studied. The results showed that in the presence of nano‐CaCO3 particles, the in situ emulsion polymerization of acrylates was carried out smoothly, and polyacrylates successfully encapsulated on the surface of nano‐CaCO3 to prepare the modified nanoparticles, breaking down nano‐CaCO3 particle agglomerates, improving their dispersion in the matrix, and also increasing the particle–matrix interfacial adhesion. Thus, the effects of the reinforcement and toughening of these modified nanoparticles on RPVC were very significant, and the cooperative effect of the nanoparticles with CPE occurred in the united modification system. Scanning electron microscopy analyses indicated that large‐fiber drawing and network morphologies coexisted in the system of joint modification of nanoparticles with CPE. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3940–3949, 2007 相似文献
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采用结合丙烯腈含量为26%的NBR、分子量适中的悬浮法Ⅲ型PVC和BR共混,制得了综合性能较PVC/NBR并用胶优异的弹性体。优选的工艺条件为:PVC/NBR/BR=30/60/10(质量比);补强剂选用炭黑40份,超细碳酸钙50份,轻质碳酸钙20份;硫化体系选用过氧化物加少量硫磺;混炼温度为140—170℃,混炼时间为10—15min。通过电子显微镜和动态力学分析,弹性体存在两个T,PVC为分散相,橡胶为连续相。 相似文献
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Joseph Berger 《Polymer》1984,25(11):1629-1632
New light-sensitive polymers were prepared by modification of four different elastomers with 4-(N-dimethylmaleimido)-benzenesulphenyl chloride (DMI-BSCI). Polydienes modified by DMI-BSCI form block copolymers. These polymers show a strong increase of the glass transition temperature Tg whereby the Tg increase of modified poly(octenamer) is much smaller. Higher modified polydienes have two Tg. Modified poly(octenamers) show a melting temperature dependence Tm on the content of trans double bonds which is characteristic of statistical copolymers. The ratio of rate constants with which trans- and cis-structures in poly(octenamer) are occupied by DMI-BSCI, is 相似文献
39.
双三羟甲基丙烷丙烯酸酯的合成研究 总被引:3,自引:1,他引:2
采用酰氯法合成双三羟甲基丙烷丙烯酸酯.实验考察了原料配比、反应温度以及阻聚剂的用量等因素对产品酯化率的影响,确定了适宜的反应条件.酯化反应的酯化率最高可达89%.生成的产物为浅黄色黏稠状液体.产物经红外光谱、质谱定性分析,确定为目的产物. 相似文献
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