羟基基团对PBO纤维表面性能及界面粘结性能的影响
详细信息Effect of hydroxyl polar groups on the surface and the interfacial adhesion properties of PBO fiber
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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，DHPBO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%。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 elect ron microscopy. With the incorporation of 50 mol% 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 43.96 mJ/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.
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