DSC Study of Thermal Properties of Biodegradable Poly(Butylene Succinate-co-terephthalate)

Poly （ butylene succinate ） （ PBS ）, poly （ butylene terephthalate） （PBT） and poly （butylene succirmte-coterephthalate） （PBST）s were synthesized from dimethyl succinate and/or dimethyl terephthalate reacting with 1,4- butanediol through a process of transesterification/ polycondmsation in the presence of a high effective catalyst and characterized by means of GPC and DSC. The investigation was mainly focused on the influence of content of terephthalate units on the molecular weight and thermal properties of resulting polymers. It is revealed that the melting temperature and crystallinity of synthesized polymers decrease first with the increase of terephthalate units, then shift to rise gradually by DSC measurements. The results of Flory equation suggest sequence structure of PBSTs is random.

丙三醇对PBST共聚酯结构和性能的影响

基于生物可降解性聚酯——聚丁二酸-共-对苯二甲酸丁二醇酯(PBST),通过原位添加不同含量的丙三醇作为第四单体,制备出共聚改性的PBST共聚酯。通过核磁共振仪(NMR)、差示扫描量热仪(DSC)、广角X射线衍射仪(WAXD)及接触角测试,分别对PBST共聚酯的结构和性能进行了研究。结果表明:丙三醇的加入并没有改变PBST共聚酯的化学组成和结构;随着丙三醇含量的增加,共聚酯的玻璃化转变温度先上升后下降,而熔点是逐步降低的;改性前后和拉伸前后PBST的晶型均未发生变化,但分子结构的规整性受到破坏,且发生拉伸诱导取向;改性PBST共聚酯的亲水性能较纯PBST有明显提高。