橡胶改性环氧树脂的固化诱导相分离

研究了一种新型的液体橡胶ZR与环氧树脂的固化反应诱导相分离过程,分别通过时间分辨的激光光散射、光学显微镜研究了两相结构的发展,并用DSC跟踪该体系的固化动力学。结果表明,该固化反应经历了不稳相分离过程(spindodal decomposition),固化动力学过程与相分离过程有强烈的依赖性,固化速度越快,橡胶相尺寸越大;并且当环氧固化反应转化率达80％时,橡胶相结构基本得以固定,最终得到双连续结构。     

柔性高分子/液晶体系的相分离

从分子场理论出发,推导出了spinodal方程和浓度效应引起的各向同性-各向异性转变方程.计算结果表明,在柔性高分子/小分子液晶的相图上除了具有经典的各向同性spinodal线以外,还存在鲜为报道的各向异性spinodal线,这两种不同的spinodal线通过各向同性-各向异性转变线连接在一起.在柔性高分子/小分子液晶的相图的不同区域中将会发生不同的相分离机理.这一体系的相平衡线不一定与spinodal线会聚于临界点.这些结果有助于我们深入了解高分子/液晶体系与一般高分子/溶剂或高分子/高分子体系不同的特殊性质,从而达到控制材料的结构与性能的目的.     

Phase separation in mixtures of thermotropic liquid crystals and flexible polymers

The spinodal equation and the concentration-induced anisotropic-isotropic transition equation of the mixtures of thermotropic liquid crystals and flexible polymers have been studied by using the molecular field theory The calculations of the phase diagrams of this system show that,besides the isotropic classic spinodal curve,there ex ists an anisotropic spinodal curve which has not been reported in literature.These two spinodal curves can be linked up by the concentration-induced anisotropic-isotropic transition line.In the various phase regions,demixing may take place due to different phase separation mechanisms.The phase equilibrium curve cannot always join the.spinodal curve at a critical point.These results are considered very meaningful for the understanding of the special properties of liquid crystal/polymer composites and very useful for controlling the morphology and the performance of PDLC materials     

Reaction-induced phase separation in rubber-modified epoxy resin

The phase separation mechanism,and structure development during curing of epoxy with a novel liquid rubber-ZR were investigated by time-resolved light scattering,optical microscope and differential scanning calonmetry (DSC) The mixture loaded with curing agent was a single-phase system in the early stage of curing.When the cure reaction proceeded,phase separation took place via the spinodal decomposition induced by polymerization of epoxy resin.This was supported by the characteristic change of light scattering profile with curing time.Cure reaction plays an important role in the progress of phase separation.The bigger the cure reaction rate is,the longer periodic distance will be.The overall two-phase structure was basically locked in when the conversion approached 80% estimated by DSC,and finally the co-continuous two-phase structure was successfully obtained.     

高聚物裂解色谱数据库的设计与检索

用保留指数表征高聚物裂解气相色谱谱图,根据高聚物的分子结构与使用性能的持点建立索引结构,在此基础上设计了裂解色谱谱图数据库软件。依据谱图相似系数进行谱图检索,给出检索的候选高聚物集合与最可能检索结果。