聚苯乙烯-b-聚2(5)-乙烯基对(间)苯二甲酸二钠嵌段共聚物的合成及其对PET结晶行为的影响

SYNTHESIS OF POLYSTYRENE-b-POLY(SODIUM VINYLTEREPHTHALATE) BLOCK COPOLYMER AND THEIR EFFECT ON PET CRYSTALLIZATION

通过原子转移自由基聚合合成了线形及三臂聚苯乙烯-b-聚2(5)-乙烯基对(间)苯二甲酸二钠嵌段共聚物,通过凝胶渗透色谱、核磁共振和热失重表征证实得到了结构明确、分散度较窄的嵌段共聚物成核剂.采用熔融共混的方法制得聚对苯二甲酸乙二酯(PET)与成核剂共混样品.采用差示扫描量热仪与一维X射线衍射仪研究了PET及添加成核剂后PET的非等温结晶过程,对不同结构和组成成核剂的成核效果进行对比研究,结果表明所合成的一系列共聚物都能有效改善PET结晶过程,同时还能有效保持PET分子量。

A series of block copolymers of styrene and sodium 2-vinylterephthalate（sodium 5-vinylisophthalate） was synthesized via atom transfer radical polymerization（ATRP）.Their structures were confirmed by 1H-NMR,gel permeation chromatography（GPC）,and thermogravimetric analysis（TGA）.These copolymers had good thermal stability and were used as nucleating agents for PET.Differential scanning calorimetric（DSC） experiments were carried out to study the relationship between polymer structures and the effect on improving the crystallization of PET.Compared with pure PET,PET/copolymer blends showed higher crystallization temperatures and higher crystalline enthalpies.Ubbelohode viscometer was used to measure the intrinsic viscosities of PET and PET/copolymer blends.One-dimensional wide-angle X-ray diffraction（1D WAXD） experiments were carried out to determine the crystalline structure of samples.The results indicated that all these block copolymers were effective PET nucleating agents.They were able to not only improve the crystallization process of PET,but also retain the molecular weights of the samples.