PBT／PCET共混体系的研究

STUDY ON PBT/PCET BLEND

本研究工作表明，以在ＰＥＴ分子链中引入少量柔性链分子如对苯二甲酸丁二醇酯、己二酸乙二醇酯等组成的共聚酯（ＰＣＥＴ）与ＰＢＴ共混，相对ＰＢＴ／ＰＥＴ共混体系，ＰＥＴ／ＰＣＥＴ共混体系的结晶度明显提高，即结晶更加完全，且以引入己二酸乙二醇酯效果更好；随共聚酯中ＰＢＴ含量增加，共混体系中ＰＢＴ结晶度一般升高，而ＰＣＥＴ结晶度降低；共混体系即使从熔体以３２０℃／ｍｉｎ快速冷却，其结晶也是完全的。在再升温过程中并未出现再结晶峰，但在２０３℃左右有一小的结晶熔融峰，这可能是生成少量小尺寸晶体或有某些缺陷晶体的缘故。

Copolyester(PCET)are prepared by copolycondensation of ethylene terephthalate and small amount of supple monomers such as butyl terephthalate(or PBT oliglomer)and ethylene glycol adipate. Compared with PBT/PET blend,the crystallinity of PBT/PCET blend is enhanced obviously,and the effect of ethylene glycol adipate is better,the crystalinity of PBT increases and that of PCET decreases with the increase in PBT content of copolyester in PBT/PCET blend.The fully crystallization takes place during cooling even at fast quench rate of 320℃/min from molten in PBT/PCET blend,but the blends have a small molten peak at about 203℃, which may be because of the formation of small dimensions or defect crystals during fast cooling.