Order and disorder in Polymer Systems : Structure and Dynamics

1.线性聚合物在溶液和体态下的动态和静态性质：(1)用介电色散方法研究了浓缩态柔性聚合物的动态性质，揭示了旋转模型理论中的一些问题。对于聚合物材料，用以下方法研究了玻璃温度附近的大变形和局部分子运动的力学响应：(A)使用双峰分布的聚合物样品，(B)测量微分动态穆杜勒，(C)研究单轴和双轴拉伸变形，以及(D)同时测量动态粘弹性和双折射。聚合物在玻璃化温度附近的运动分为两种类型，每种类型都有分子解释。(2)用不同于柔性聚合物的分子理论解释了刚性链聚合物体系的静态性质、热力学性质和空间性质。用红外二向色性研究了聚合物共混体系中高分子链之间的各向异性相互作用，结果表明各向异性相互作用对共混物的相容性能有重要影响。在均相线性聚合物体系的基础上，将研究扩展到以下体系：(A)支化聚合物[星形和树状聚合物，聚(大单体)S]，(B)化学和物理交联聚合物凝胶，(C)宏观和微观相分离的聚合物体系，以及(D)界面聚合物。新的计算机模拟技术被应用于系统(A)和(C)，新的理论被发展用于系统(A)-(D)，新的实验技术(例如，中子散射和折射率测量)被用于研究系统(B)和(D)。

1.Dkynamic and static properties of linear polymers in the solution and bulk states.(1)Dynamic properties Dynamics of flexible polymers in concentrated systems was studied by dielectric dispersion method, which revealed some problems in the reptation model theories. For polymeric materials, mechanical responses to large deformation and local molecular motion near the glass temperature were investigated by the following methods : (a)the use of bimodal-distribution polymer samples, (b)the measurement of differential dynamic mudulus, (c)the study of the uniaxial and biaxial extension deformations, and(d)the simultaneous measurements of dynamic viscoelasticity and birefringence. The polymer motion near the glass temperature classified into two types, each of which was molecularly interpreted.(2)Static properties Thermodynamic and spatial properties of stiff-chain polymer systems were explained by molecular theories different from theories of flexible polymers. Anisotropic interaction between polymer chains in polymer blend systems was studied by infrared dichroism, and it was shown to be important for the miscibility of the blends. The screening of the intramolecular excluded volume effect was studied by computer simulation.2.Polymeric systems with current interestsOn the basis of the above results for homogeneous systems of linear polymers, the research was extended to the following systems with current interests : (a)branched polymers [star-shaped and tree-like polymers, poly(macromonomer)s], (b)chemically and physically cross-linked polymer gels, (c)macro-and micro-phase-separated polymer systems, and(d)polymers in interface. New computer simulation techniques were applied to the systems(a)and (c), new theories were developed for the systems(a)-(d), and new experimental techniques(e.g., neutron scattering and refractivity measurements)were used to study the systems(b)and(d).