以对苯二酚二对苯甲酸酯（HQB）、N,N’-二（ω-羟乙基）苯均四甲酰二亚胺（BHDI）、甲苯二异氰酸酯（TDI）为单体,利用溶液缩聚方法,合成了一种含有亚氨基的新型液晶聚氨酯（HBLCP）,并将该液晶聚氨酯与环氧树脂（E-51）共混制备液晶聚氨酯/环氧树脂复合材料（HBLCP/E-51）。采用FTIR、DSC、POM和WAXD等方法对HBLCP的结构和液晶相转变行为进行了表征,并利用SEM观察复合材料断裂形貌,探讨其增韧机制。结果表明,加入质量分数为3%的HBLCP,可使HBLCP/E-51复合材料的冲击强度提高2.3倍,拉伸强度和弯曲强度也有不同程度的提高,呈现出典型的韧性断裂,热分解温度提高12~20℃,出现最大分解速率时的温度提高12~15℃。
Liquid crystal polyurethans（HBLCP） containing imide units were synthesized by polyaddition reaction of N,N＇-bis（2-hydroxyhexyl）-dicarboxyimide（BHDI） with 2,4-toluenediisocyanate（2,4-TDI） and hydroquinone dibenzoate ester（HQB） through changing the molar ratio of BHDI and HQB,and blending HBLCP with epoxy resin（E-51）,to prepare HBLCP/E-51 composites.The structure and liquid crystalline phase behavior of HBLCP were characteristied by using FTIR,DSC,polarized light microscopy（POM）,X-ray diffraction（WAXD）,and the fracture structure of the HBLCP/E-51 composites was investigated by SEM,and the toughening mechanism was also explored.Experimental results reveale that the impact strength of the epoxy resin modified with 3 wt% HBLCP is 2.3 times higher than that of unmodified epoxy resin,and the tensile strength as well as the bending strength is also improved,present the typical ductile fracture.The thermal decomposition temperature of HBLCP/E-51 composites is also 12~20 ℃ higher than that of the pure epoxy resin,and the temperature for the maximum decomposition rate of composites is 12~15 ℃ higher than that of the pure epoxy resin.
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