聚酯/液晶聚合物共混纤维的热处理

采用Ｘ射线衍射法、双折射法以及声速法研究了ＰＥＴ及其与液晶聚合物（ＬＣＰ）的共混初生纤维以及经过热处理后纤维的结晶结构和取向结构，并用应力－应变（Ｓ－Ｓ）法测定其断裂强度和初始模量。结果表明，ＬＣＰ的加入使初生纤维取向度和结晶度均下降，而喷头拉伸率增大则使共混初生纤维的结晶度和取向度均提高；由较大喷丝头拉伸率得到的共混纤维经热处理后取向度下降，而结晶度增大；当ＬＣＰ含量大于或等于１０％时，经热处理后共混纤维取向度下降；纤维２１０℃热处理后的晶粒尺寸明显大于１８０℃处理的，且前者的纤维各晶面的晶粒尺寸随着ＬＣＰ加入均有增大；纯ＰＥＴ纤维经热处理后力学性能提高，而ＰＥＴ／ＬＣＰ共混纤维热处理前后力学性能则呈较复杂的变化。

A STUDY ON THE HEAT TREATMENT OF POLYESTER/LIQUID CRYSTALLINE POLYMER BLEND FIBERS

Poly(ethylene terephthalate)/liquid crystalline polymer(PET/LCP) fibers have been heat treated at constant length under two different conditions. The crystalline and orientational structure of blend fibers before and after heat treatment were individually studied by means of X ray diffraction, birefringence and sonic velocity method. The tenacity and modulus of them were determined by stress strain(S S) method. The results show that LCP decreases the orientation of as spun blend fibers and their crystallinity. With the increase of draw down ratio both the crystallinity and orientation of PET/LCP as spun blend fibers increase. A higher draw down ratio makes the orientation of blend fibers lower and the crystallinity higher after heat treatment. When the LCP weight content is equal or higher than 10%, the orientation of blend fibers decreases after heat treatment. The crystallographic dimensions are bigger under condition(II) than under condition(I) and after heat treatment(II) the crystallite size of various crystal plane increases with the addition of LCP. The mechnical properties of virgin PET fiber are improved by means of heat treatment whereas those of PET/LCP blend fibers behave complicatedly.