Molecular Studies on Polymer Gels

聚合物凝胶的分子研究

基本信息

批准号：
63044083
负责人：
NOMURA Shunji
金额：
$ 4.16万
依托单位：
Kyoto Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1990
项目状态：
已结题

项目摘要

Structure, solgel transition behavior, and dynamic aspects of polymer gels were investigated in terms of small angle neutron scattering (SANS), viscometry, forced Rayleigh scattering (FRS), fluorescence depolarization methods, and ultrasonic spectrosopy. Topological features of polymer gels were also studied by generating bimodal networks.SANS of poly (vinyl alcohol) (PVA) solutionsThe correlation length, xi, was estimated from a generalized Zimm plot for fractals having the fractal dimension of D. The variation of xi with temperature showed a gel-to-sol transition. The scattered intensity functions for the gels at different temperatures could be superimposed by employing reduced variables, I(q)/Cxi^3 and xiq, where C and q are the monomer concentration and the magnitude of the scattering vector, respectively.Phase behavior and solgel transition of PVA-borate complex in aqueous solutionsAt a given combination of PVA concentration and ionic strength, the system underwent a clear-opaque- … More clear transition with increasing boric acid concentration. This behavior was explained by a balance of the exclude volume effect due to intra- and inter-chain crosslinks and electrostatic potentials.Dynamical aspects of thermoreversible gelation of polymer solutionsSolutions of poly (n-butyl methacrylate) (PnBNA), poly (isobutyl methacrylate) (PiBMA), poly (tert-butyl methacrylate) (PtBMA) and poly (2-hydroxyethyl methacrylate) (PHEMA) in 2-propanol and 2-butanol were used as samples. The thermoreversible gelation mechanism of poly (butyl methacrylate)/2-propanol solutions strongly depends on the chemical structures of their isomers. It was also found that the elastic energy that is generated by the chemical gelation of polystyrene (PS) chains in a binary mixture of PS and poly (2-chlorostyrene) (P2CS), modifies the concentration fluctuations of PS/P2CS mixtures.Bimodal Polymer NetworksComputer simulations were performed on two and three dimensional square lattices with tetrafunctional crosslinks. The simulated networks demonstrated the presence of appreaciable of number of network imperfections, such as unsatisfied crosslinks (chain extenders), isolated chains, unreacted crosslink agents, and dangling chains. It was found that the simulated chains re-produced several topological features of real elastomers. Less

通过小角中子散射（SANS）、粘度测定、受迫瑞利散射（FRS）、荧光去偏方法和超声光谱研究了聚合物凝胶的结构、溶胶凝胶转变行为和动力学方面。通过生成双峰网络。聚（乙烯醇）（PVA）溶液的 SANS 相关长度 xi 是根据分形的广义 Zimm 图估计的，具有D 的分形维数。xi 随温度的变化显示出凝胶到溶胶的转变，不同温度下凝胶的散射强度函数可以通过使用简化变量 I(q)/Cxi^3 和 xiq 进行叠加，其中。 C 和 q 分别是单体浓度和散射矢量的大小。水溶液中 PVA-硼酸盐复合物的相行为和溶胶凝胶转变在给定的 PVA 浓度和离子强度组合下，系统经历了透明-不透明-…随着硼酸浓度的增加，这种行为可以通过链内和链间交联和静电势引起的排除体积效应的平衡来解释。聚合物溶液热可逆凝胶化的动力学方面。甲基丙烯酸正丁酯(PnBNA)、聚甲基丙烯酸异丁酯(PiBMA)、聚甲基丙烯酸叔丁酯(PtBMA)和以聚(甲基丙烯酸2-羟乙酯)(PHEMA)在2-丙醇和2-丁醇中的溶液为样品，聚甲基丙烯酸丁酯/2-丙醇溶液的热可逆凝胶机理取决于其异构体的化学结构。还发现，在 PS 和聚（2-氯苯乙烯）的二元混合物中，聚苯乙烯（PS）链化学凝胶化产生的弹性能(P2CS)，改变 PS/P2CS 混合物的浓度波动。双峰聚合物网络对具有四官能交联的二维和三维方形晶格进行了计算机模拟，模拟网络表明存在大量网络缺陷，例如不令人满意的交联（扩链剂）、孤立链、未反应的交联剂和悬挂链被发现重新产生了模拟链。真实弹性体的几个拓扑特征。