▎ 摘　　要

NOVELTY - Binary graft-modified polybenzoxazole fiber is prepared by combining 10-100 ml thionyl chloride and 1-5 ml N,N-dimethylformamide, adding 0.1-0.4 g graphene oxide powder, ultrasonicating for 0.5-2 hours, heating and refluxing under nitrogen atmosphere for 12-72 hours, distilling under reduced pressure to remove solvent and obtain functionalized graphene oxide, winding polybenzoxazole fiber around square glass frame, immersing in sulfuric acid solution, stirring at room temperature for 1-4 hours, taking out, washing with deionized water 1-7 times, and drying at 80-150 degrees C for 10-60 minutes. USE - Preparation of binary graft-modified PBO fiber (claimed). ADVANTAGE - Binary graft-modified PBO fiber has improved wettability, tensile strength retention rate, interfacial shear strength, and contact area between fiber surface and resin matrix. DETAILED DESCRIPTION - Binary graft-modified polybenzoxazole (PBO) fiber is prepared by combining 10-100 ml thionyl chloride and 1-5 ml N,N-dimethylformamide, adding 0.1-0.4 g graphene oxide powder, ultrasonicating for 0.5-2 hours, heating and refluxing under nitrogen atmosphere for 12-72 hours, distilling under reduced pressure to remove solvent and obtain functionalized graphene oxide, winding PBO fiber around square glass frame, immersing in sulfuric acid solution, stirring at room temperature for 1-4 hours, taking out, washing with deionized water 1-7 times, 1st drying at 80-150 degrees C for 10-60 minutes to obtain activated PBO fiber, adding 0.02-0.08 g activated PBO fiber to 25-100 ml lithium aluminum hydride-diethyl ether saturated solution, heating and refluxing under nitrogen atmosphere for 0.5-2 hours, washing with deionized water 1-7 times, 2nd drying at 80-150 degrees C for 10-60 minutes to obtain hydroxyl-functionalized PBO fiber, adding 0.5-2 ml 3-aminopropyl trimethoxysilane (APTMS) to 50-150 ml anhydrous ethanol, mixing, adding 0.02-0.08 g hydroxyl-functionalized PBO fiber, stirring at 30-60 degrees C for 6-24 hours, washing with anhydrous ethanol 1-7 times, 3rd drying to obtain APTMS-grafted PBO fiber, dissolving 0.05-0.15 g functionalized graphene oxide in 40-100 ml N,N-dimethylformamide, ultrasonicating for 1-3 hours, adding 0.02-0.08 g APTMS-grafted PBO fiber, heating and refluxing under nitrogen atmosphere for 24-72 hours, washing with N,N-dimethylformamide 1-7 times, and 4th drying. DESCRIPTION OF DRAWING(S) - The drawing shows a scanning electron microscope (SEM) image of binary graft-modified PBO fiber.