硅醇和芳香酯共聚改性PBS材料的制备与性能研究

Preparation and Performance of PBS-PBT-PDMS Copolymers

以丁二酸和丁二醇为原料进行熔融缩聚制得低聚物,再用低聚物与对苯二甲酸二甲酯和硅醇进行熔融缩聚制得共聚改性聚丁二酸丁二醇酯(PBS)材料。通过核磁共振谱仪、差示扫描量热仪、热重分析仪、扫描电子显微镜和万能材料试验机分别表征了该共聚物的化学结构、结晶和熔融行为、热性能、断面形貌和力学性能。结果表明,以PBS为主体、硅醇为扩链剂和增韧段、聚对苯二甲酸丁二醇酯(PBT)为增强段,共聚后获得了较高相对分子质量的线形共聚物和少量交联结构聚合物;共聚物的球晶完善程度下降,结晶度降低,但结晶速度提高;同时,该共聚物的热稳定性也在一定程度上有所提高;由于硅段的高柔顺性和PBT段的刚性,该共聚物具有优良的综合力学性能,拉伸强度提高了1.4~2.1倍,冲击强度提高了4~7倍,断裂伸长率提高了2~4倍。

An oligomer was prepared by the reaction of succinic acid with butyl glycol,and a series of copolymers were synthesized by use of the digomer,dimethyl terephthalate and silanol through melt polycondensation.Chemical structure,crystallization-melting behavior,thermal performance,morphology and mechanical properties of the resultant copolymers were characterized by ~1H-NMR,^(29)Si-NMR,differential scanning calorimetry,thermogravimetric analyzer,scanning electronic microscopy and universal testing machine. The results indicated that the copolymers were constituted by PBS as a main chain,silane segments as a chain extender and tougher and PBT bulk as a reinforcement.They not only achieved a liner molecular structure with a high molecular weight but also obtained an improvement in mechanical properties and thermal stability.Moreover,the copolymers exhibited imperfect spherulites due to the fast crystallization rate and lower crystallinity.Owing to a highly flexible silane segment and a rigid PBT segment,the copolymers achieved an increase in tensile strength by a factor of 1.4~2.1,an increase in impact strength by a factor of 4~7,and an increase in elongation at break by a factor of 2~4.