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以2,5-二羟基对苯二甲酸(DHTA)为改性单体,采用化学共聚改性的方法,合成了大分子链上含有羟基基团的聚对苯撑苯并二噁唑(PBO)与DHTA的共聚物(DHPBO),并通过液晶纺丝技术得到了DHPBO纤维。利用FTIR、接触角等分析手段对其化学结构和纤维表面性能进行了表征,并通过微脱粘实验和SEM评价了DHPBO纤维与环氧树脂基体的界面剪切强度。结果表明:50 mol%DHTA的加入使水在PBO纤维表面的接触角由71.4°减小到50.7°,乙醇在PBO纤维表面的接触角由37.2°减小到27.4°;当DHTA含量为20 mol%时,DHP-BO纤维的表面自由能增加到43.96 mJ/m2,比PBO纤维提高了23.83%。当DHTA含量为10 mol%时,DHPBO纤维与环氧树脂的界面剪切强度为18.87 MPa,比PBO纤维与环氧树脂的界面剪切强度提高了92.55%。
Poly (p-phenylenebenzobisoxazole) (PBO) with hydroxyl groups on the macromolecular chains was synthesized by the chemical copolymerization of 2,5-dihydroxyterephthalic acid (DHTA) ) With DHTA (DHPBO), and DHPBO fibers were obtained by liquid crystal spinning technique. The chemical structure and surface properties of the fibers were characterized by FTIR, contact angle and other analytical methods. The interfacial shear strength between DHPBO fibers and epoxy matrix was evaluated by micro-debonding test and SEM. The results showed that the contact angle of PBO fiber decreased from 71.4 ° to 50.7 ° with the addition of 50 mol% DHTA, and the contact angle of ethanol with PBO decreased from 37.2 ° to 27.4 °. When the DHTA content was 20 mol %, The surface free energy of DHP-BO fibers increased to 43.96 mJ / m2, which was 23.83% higher than PBO fibers. When DHTA content is 10 mol%, the interfacial shear strength between DHPBO fiber and epoxy resin is 18.87 MPa, which is 92.55% higher than the interfacial shear strength between PBO fiber and epoxy resin.