PET－PBT共聚酯的结构与结晶性能

用差示扫描量热法（ＤＳＣ）、核磁共振技术（ＮＭＲ）以及红外光谱等方法对经共缩聚而制得的ＰＥＴ－ＰＢＴ共聚酯进行了结构和性能分析。ＰＥＴ－ＰＢＴ共聚酯为嵌段共聚物，两种链段的非晶区是相溶的，只观察到１个玻璃化转变温度Ｔｇ，而它们的晶相是分离的。随着ＰＥＴ－ＰＢＴ共聚酯中ＰＢＴ链段含量提高，共聚结晶熔点不断下降，Ｔｇ也有下降趋势。ＰＢＴ链段的引入增强了ＰＥＴ分子链段的柔顺性，有利于提高ＰＥＴ链段的结晶能力。另一方面，少量ＰＢＴ链段的引入，也破坏了ＰＥＴ分子链的规整性，不利于其结晶。由于这两方面的原因，在低ＰＢＴ链段含量时，ＰＥＴ－ＰＢＴ共聚酯的结晶能力改善并不十分明显。

STRUCTURE AND CRYSTALLIZATION BEHAVIOR OF PET PBT COPOLYESTER

A lot of modern detection technology have been utilized to investigate the structure and properties of PET PBT copolyester, which was synthesised through condensation polymerization between PBT oligomer and PET oligomer. The results indicated that PET PBT copolyester is block copolymer. Only one glass transition temperature T g can be found, which showed the miscibility of PBT and PET segments in amorphous phase but they crystallized separately acording to its own cell. With increasing the PBT segments content in PET PBT copolyester, the melting point and T g depress. The introduction of PBT segments in the copolyester is favorable for PET crystallization. In another view, the introduction of PBT segment in the copolyester decreased the regularity of PET, which is unfavorable for PET crystallization. When PBT content is low in the PET PBT copolyester, the improvement of PET PBT crystllization ability is weak.