【摘要】 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%。更多还原

【Abstract】 The modified poly(p-phenylene benzoxazole)(PBO) containing polar hydroxyl groups in macromolecular chains was obtained by copolymerization from 1,3-diamino-4,6-dihydroxybenzenedihydroch1oride(DAR) and terephthalic acid(TPA)in poly(phosphoric acid)(PPA)solvent,with addition of certain amounts of 2,5-dihydroxyterephthalic acid(DHTA) to replace TPA.The obtained DHPBO-PPA dope was directly spun into fibers via a dry-jet wet-spinning process.The resultant polymers were characterized mainly by means of FTIR,dynamic contact angle analysis,etc.The interfacial shear strength(IFSS) was determined by the microbond pull-out test.The surface morphologies of the pull-out PBO and DHPBO fibers were observed by scanning electron microscopy.With the incorporation of 50mol% hydroxyl polar groups,the contact angle on PBO fiber for water decreases from 71.4° to 50.7°,and the contact angle for ethanol decreases from 37.2° to 27.4°.The surface free energy of DHPBO(20%mol content of DHTA)fiber increases to 43.96mJ/m2,which is 23.83% higher than that of PBO fiber.The IFSS between DHPBO(10% mol content of DHTA) fibers and epoxy resin is 18.87 MPa,which is 92.55% higher than that of PBO fibers.更多还原