| Summary: | 碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 88 === The effects of dielectric relaxation behaviors on polyarylates with para or meta linkage in the main chain were studied using a dielectric analyzer. The amount of para and meta linkage in the polyarylates was controlled either by chemical synthesis (to obtain copolymer) or by physical blending. The bisphenol A was used as polyol component of polyarylate. The isophthaloyl chloride (Iso) and terephthaloyl chloride (Tere) were used as polyacid component of polyarylate with meta linkage and para linkage respectively.
There are two relaxation in both copolymers and blending samples. One of them is glass-rubber alpha relaxation, the other is sub-glass beta relaxation.
The molar ratio of Iso/Tere influences alpha-relaxation greatly. The higher the isophthaloyl content is, the lower the glass transition temperature was measured and the higher the relaxation intensity is. Because of the localized motions of beta-relaxation, the molar ratio of Iso/Tere is no effect on beta-relaxation.
When the blending samples were compared with copolymers, the different degree of physical and chemical mix held the key of problems. The worse miscibility of the blending samples result in the broader beta-relaxation energy distribution. But we need more information to recognize the issue.
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