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Synthesis And Crystallization Behavior Studies Of Biodegradable Poly (Butylene Succinate), Poly (Ethylene Succinate) And Their Copolymers

Posted on:2012-03-29Degree:MasterType:Thesis
Country:ChinaCandidate:Y YangFull Text:PDF
GTID:2211330368458532Subject:Materials Science and Engineering
Abstract/Summary:PDF Full Text Request
Poly(butylene succinate) (PBS) and its copolymers poly(butylene succinate-co-ethylene succinate)(P(BS-co-ES)) were synthesized by a two-step melt-polycondensation method. Various techniques, such as WAXD, DSC, and POM were first used to investigate neat PBS and P(BS-co-ES) with the ethylene succinate (ES) comonomer contents of 13, 21 and 28 mol% in detail. The effects of ES unit on the crystal structure, basic thermal behavior, isothermal crystallization, crystallization(?)growth kinetics of P(BS-co-ES) were discussed. It is found that the ES unit does not change the crystal structure and crystallization mechanism of the copolymers; however, it hinders the movement of molecular chains of P(BS-co-ES), resulting the decrease of the nonisothermal crystallization, isothermal crystallization and spherulitic growth rates. In addition, the nucleation density of P(BS-co-ES) decreases with increasing crystallization temperatures and ES contents. As to spherulitc growth kinetics, a crystallization regimeⅡ-regimeⅢtransition was observed in all P(BS-co-ES) copolymers and the transition temperature moves towards lower temperature with the increase of ES contents.On the other hand, various crystallization behaviors of poly(ethylene succinate-co-butylene succinate) (P(ES-co-BS)) with BS contents of 6 and 13 mol% have been studied, including crystal structure, basic thermal behavior, crystallization kinetics, spherulitic morphology, and spherulitic growth kinetics and compared with those of neat PES. It is found that the crystal structure of P(ES-co-BS) cannot be modified but the crystallinity decreased by the incorporation of a samll amount of BS contents, indicating the BS unit does not crystallize and exists in the amorphous state. Besides, BS contents hinder the motion of the molecular chains which leads to the decrease of the crystallization rate even though with a small quantity in P(ES-co-BS). A crystallization regimeⅡ-regimeⅢtransition was detected in both P(ES-co-BS) and neat PES.
Keywords/Search Tags:Poly(butylene succinate-co-ethylene succinate), crystal structure, crystallization behavior, thermal behavior, spherulitic morphology, crystallization regime transition
PDF Full Text Request
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