热致液晶性纤维素芳族酯的制备及其对PET结晶成核作用的研究

STUDY ON PREPARATION OF A CELLULOSE AROMATIC ESTER THERMOTROPIC LIQIID CRYSTAL AND ITS EFFECT ON POLYETHYLENE TEREPHTHALATE CRYSTALLIZATION

以棉纤维为原料，制备了一种纤维素芳族酯（ＣＡＥ）。用ＦＴ－ＩＲ表征了ＣＡＥ的化学结构，用ＤＳＣ及热台偏光显微观察证实了ＣＡＥ具有热致液晶性，液晶态温度范围为２１０～２８０℃。结晶速度测试表明，ＣＡＥ对ＰＥＴ有明显的成核和促进结晶作用。

A cellulose aromatic ester (CAE) was prepared by esterifying reaction from cotton linters and an aroyl chloride in the presence of eatalyzer.The degree of substitution of the resultant determined by FT-IR and elementary analysis is about 2. 8. The DSC measurement and polarizing microsocpe observation show that CAE has typical thermotropic liqiud crystalline properties with a solide stateliquid crystal state transition temperature T(SL)=210 ℃ (transition enthalpy △H1= 1. 492 J/g) and a liquld crystal state-isotropic liquid state one T(LI)= 280 ℃(△H2= 14. 681 J/g). The isothermal crystallizing rates of PET/CAE systems were measured from 100℃ to 160℃,and the data were analysed by Avrami equation. The results show that the nucleation and the acceleration on crystallization of CAE on PET are very evident, 0. 5% (mass) CAE can increase the isothermal crystallizing rate at 120 ℃ of PET over 8 times.