共聚酯的结晶性能研究

CRYSTALLIZATION BEHAVIOR STUDY OF COPOLYESTER

用 DSC、WAXD及密度法 ,研究了不同间苯二甲酸乙二酯 (EI)含量共聚酯 (PEIT)的结晶性能。结果表明 ,随间苯含量增加 ,PEIT结晶性能变差。间苯含量达到某一定值 A2 时 ,共聚酯 PEIT- A2 切片的结晶性能 ,比相同条件下较高间苯含量的共聚酯 PEIT- A3 差 ;PEIT- A2 纤维在冷拉伸条件下结晶度与 PEIT- A3的近乎相等 ,在拉伸、热的双重作用下结晶度又大于 PEIT- A3纤维。共聚酯 PEIT- A2 的结晶性能对拉伸应力和热的敏感度远大于 PEIT-A3。讨论了

Crystallization behavior of PEIT with different isophthalate composition(<25%) has been investigated by DSC, WAXD, density measurement. The results show that the crystallinity of PEIT decreases with increasing isophthalate composition. When isophthalate content reaches to a certain value A 2(A 1<A 2<A 3<25%), the crystallinity is smaller than that of PEIT containing more isophthalate composition(A 3) as cooling from melt at constant rates or crystallizing isothermally at 120 ℃ for 8 h. The crystallinity of PEIT A 2 cold drawn filament appears almost the same value to that of PEIT A 3. The crystallinity of PEIT A 2 becomes larger than that of PEIT A 3 by both effects of heat and stress. PEIT A 2 crystallization is more sensitive to drawing and heating than PEIT A 3. The relationship between sequence distribution in PEIT and crystallization behavior has been discussed.