The Surface Modification Of High-Performance PBO Organic Fiber

PBO[poly(p-phenylene-2,6-benzobisoxazole)]has high strength,high modulus,low-density as one of the organic fibers,with excellent thermal stability and flame retardant properties.It was known as the super fiber in 21st century.The study on the preparation and performance of PBO fibers had significant meaning for making high-performance fibers in our country and its application in aerospace industry,as well as the development of the science and technology in national defense.Although high performance PBO fiber has excellent performance on strength and modulus,but smooth surface and low activity caused that it can’t easily combined with resin,So the bonding performance between fiber and resin matrix is poor,interfacial shear strength is low.It will be impact performance of the composite materials reinforced fiber,limited the application of high-performance PBO fiber in the advanced composite materials.Chemical treatment and low temperature air plasma treatment had been used to modify the surface of the high-performance PBO fiber in the present work.The temperature is room temperature and 60 ℃ with water bath,respectively.The mixed solution of sulfuric acid and methyl sulfonic acid with five different ratios are selected for the surface treatment of the PBO fiber.The treatment time is from 2 h to 12 h.The treated fibers then washed with distilled water until the solution is neutral.Finally,the products are dried at 100℃ for 12 h.The products after treatment by sulfuric acid and methyl sulfonic acid(1:1)at room temperature and 60℃ with water bath for 2 h to 12 h arc treated by low temperature air plasma.As a control experiment,the products without acid treatment were treated by low temperature air plasma.The SEM images demonstrate that the surface of the fiber after mixed acid treatment appears obvious protuberance,even groove.The XPS analysis revealed that the polar group had been introduced to the surface of the fiber after mixed acid treatment.The mechanical property of fiber is tested by fiber monofilament tensile experiment.The result reveals that the intensity of the fiber after acid treatment decreases.The interface bonding performance of the PBO organic fiber is texted by monofilament pull out method.The result reveals that the interfacial shear strength between the treated fiber and resin matrix increases obviously.The experimental results showed that,compared with untreated PBO fiber,PBO fibers treated in 60%MSA at 60℃ for 6 h had excellent surface properties.The IFSS of treated PBO fiber-epox resinincreased by 26.7%.The decreased degree of strength was 17.6%.Under the optimum parameters of 170 W and 10 min,the IFSS was improved by 35.1%,while the intensity decreases by 2.7%.The surface rough degree and oxygen content are the greatest.