芳香族热致液晶聚（对羟基苯甲酸－对苯二甲酸双酚A酯）的流变性能

Rheological Properties of Liquid Crystalline Aromatic Copolyestsr Melts

用Ｉｎｓｔｒｏｎ３２１１型毛细管流变仪研究了以对羟基苯甲酸（ＰＨＢ）、对苯二甲酸（ＴＰＡ）和双酚Ａ（ＢＰＡ）为单体合成的共聚芳酯液晶熔体的流变性能。结果表明，切变速率、熔体温度及ＰＨＢ链节含量对切粘度和结构粘度有很大的影响。切变速率在１０～１０３／Ｓ、温度２９５～３３０℃范围内，共聚酯粘流活化能△Ｅη为７４．５～２０５．１（ｋＪ／ｍｏｌ）。液晶熔体在剪切流中存在屈服应力τｏ，随温度升高τｏ值降低。在低温、低切变速率下，共聚酯熔体的弹性很小，甚至呈现挤出收缩现象。

arious aspects of the rheological behavior of liquid crystalline copolyesters based on p-hydroxybenzoic acid, terephthalic acid and bisphenol A were explored by using instron capillary rheometer. The experimental results indicated that the apparent viscosity was significantly affected by shear rate, melt temperature and PHB unit content, and the flow-activation energies BE, are 74.5 to 205. 1 kJ / mol over the shear rate of 10-1000 s- at temperature 295 to 330℃. These copolyesters exhibit yield stress in shear now, and with increasing temperature, the yield values decreased. The extrudate contracted at lower temperature and shear rates.