新型液晶聚氨酯/环氧树脂复合材料的制备及性能

以联苯二酚,2,4-甲苯二异氰酸酯(2,4-TDI),乙二醇,N,N'-二(ω-羟乙基)均苯四甲酰二亚胺(BHDI)为单体,加成反应合成了1种同时含有联苯基和亚胺基的新型液晶聚氨酯(LCPBI),通过IR,DSC、偏光显微镜及X射线衍射仪对其结构和性能进行表征和分析。将该液晶聚氨酯与环氧树脂(E-51)共混制备了液晶聚氨酯/环氧树脂复合材料,通过力学性能测试,热重分析和电镜分析对其性能进行了研究并探讨了其增韧机理。结果表明,加入质量分数为3%的LCPBI,可使复合材料的冲击强度提高2.5倍,拉伸强度和弯曲强度也有不同程度的提高,热分解温度提高15～20℃。

Preparation and properties of novel liquid crystalline polyurethanes/epoxy resin composites

The novel liquid crystal polyurethans(LCPBI)containing biphenyl and imino groups were synthesized by polyaddition reaction of 4,4′-dihydroxybiphenyl,2,4-toluenediisocyanate,ethylene glycol and N,N′-bis(2-hydroxyhexyl)-dicarboxyimide(BHDI).The structure and properties of LCPBI were characterized and analized by IR,DSC,polarizing microscopy and X-ray diffraction.The composite was prepared from LCPBI and epoxy resin(E-51).The properties of the composite were investigated by mechanical property test,TGA and SEM analysis and the toughening mechanism was discussed.The results showed that the impact strength of the composites with 3% LCPBI was 2.5 times higher than that of the pure systems,The tensile strength and bending strength were also improved in different degree and the thermal decomposition temperature of modified systems was increased by 15-20 ℃