Structure Formation and Relaxation Phenomena in Polymeric Systems

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Experiments and analysis were performed for the following three kinds of polymers.1. Polyethylene terephthalate : Simultaneous real-time measurements of dielectric relaxation and x-ray scattering were performed. Before crystallization is observed, the dielectric primary relaxation changes into another relaxation, then the change in dielectric relaxation occurs accompanying the crystallization. This phenomena are interpreted as follows : the mode of molecular motion in amorphous region changes prior to crystallization and then the mode changes into the one constrained by the crystalline lamellae.2. Isotactic polystyrene : The dependence of growth rate and morphology on crystallization conditions was examined by x-ray scattering, atomic force and electron microscopies, . In the crystallization in thin film, it is shown that crystal morphology and the defects are affected by the substrates and that the morphology becomes diffusion-controlled with decreasing film thickness. Further, the growth rate is shown to be reciprocally proportional to the film thickness, and the results were interpreted in terms of the reptation model.3. Isotactic Polypropylene : The higher-order structure formation process is shown not to be spinodal-like but the nucleation process by the x-ray scattering. The glass transition temperature is found to decrease with the formation of smectic phase.