聚酯-聚醚多嵌段共聚物的共聚改性

高硬段含量和高软段分子量的聚酯-聚醚多嵌段共聚物有明显的组成不均一性,可分离出大量高熔点的氯仿不溶组份.通过和5mol%间苯二甲酸二甲酯(DMI)共聚,可改进其表观组成均一性,得到不含氯仿不溶物和力学性能优良的硬段含量为40wt%、软段分子量为4000的聚对苯二甲酸乙二酯-聚乙醇醚多嵌段共聚物(PET-PEG).另一合成途径是以间苯二甲酸(IPA)酸解 PET,再和端羟基聚乙二醇醚共缩聚,也可制得相应的改性 PET-PEG.降低聚醚分子量可以有效地改进其组成均一性.

MODIFICATION OF POLYESTER-POLYETHER MULTIBLOCK COPOLYMERS VIA COPOLYMERIZATION

Polyester-polyether multiblock copolymers with relatively high content of hard segment and molecular weight of soft segment exhibit low compositional homogeneity and a large amount of CHCl_3 insoluble fraction with high melting point can be separated out.The addi- tion of 5% mol of dimethyl isophthalate(DMI)as a comonomer during ester exchange reaction much improves the apparent compositional homogeneity of the multiblock copolymers. The polyethylene terephthalate-polyethylene glycol ether multiblock copolymers(PET-PEG) with hard segment of 40 wt % and PEG molecular weight of 4000 were synthesized with excellent mechanical properties and no CHCl_3 insoluble fraction.An alternative synthetic route has also been explored,according to which the PET is first acidolysed by isophthalic acid(IPA)and then copolycondensized with OH-terminated PEG to prepare PET-PEG with isophthalate units in hard segments.The compositional homogeniety of PET-PEG obtained greatly increases as the molecular weight of PEG decreases.