一种低支化聚酯液晶的合成及性能表征

The Synthesis and Characterization of a Kind of Low Branching Crystal Polyester

采用不同比例的4,4′-对苯二甲酰二羟苯甲酸乙二醇酯（TOBB）与偏苯三酸酐（TMA）反应,合成端基含有羧基的哑铃型聚酯液晶和低支化度的聚酯液晶。通过红外光谱（FT-IR）、差示扫描量热（DSC）、偏光显微镜（POM）、广角X射线衍射（WAXD）及热重分析（TGA）等对其结构及性能进行表征。结果表明,所合成的聚酯液晶呈现出典型的向列型热致性液晶的特征,属于半结晶性化合物,液晶区间在50℃-60℃左右,低支化度聚酯液晶的热稳定性高于端羧基哑铃型聚酯液晶。

Two kinds of liquid crystalline polyester,which name of dumbbell-shaped liquid crystalline polymer and liquid crystal polymer with a low branching coefficient,were synthesized by 4,4′-terephthaloy dioxydibenzonic acid glycol ester（TOBB） and trimellitic anhydride（TMA） at a series of different proportions.The liquid crystalline behaviour and properties of the two liquid crystal polyester were systematically investigated with Fourier transform infrared spectrum（FT-IR）,differential scanning calorimetry（DSC）,polarizing microscope（POM）,wide angle X-ray diffraction（WAXD） and thermogravimetric analysis（TGA）.The result shows that the liquid crystal polyesters are the typical nematic liquid crystal.The temperature range of two liquid crystalline polymers exhibiting thermotropic liquid crystalline properties is 50 ℃～60 ℃.The TGA observation confirms the thermal stability of liquid crystal polymer with a low branching coefficient is better than that of the dumbbell-shaped.