Effect of carbon fiber surface treatment with HNO3 and KOH on the interfacial bonding of PMMA resin composite

Abstract This work studied the surface, interface state and physicochemical properties of HNO3-treated and KOH-treated carbon fiber. Poly(methyl methacrylate) (PMMA) composites were prepared by the autoclave molding process using surface-treated carbon fiber as reinforcements. The physical and chemical states of the carbon fiber surfaces and the micro-interface properties and interlaminar shear properties of the composites were studied. The results show that the surface of the HNO3-treated carbon fiber has more groove structure and higher surface roughness and thus forms a better physical bond with the resin matrix. Although the oxygen-containing functional groups of the two carbon fibers are equivalent, the surface oxygen of the HNO3-treated carbon fiber is relatively high, which is beneficial to form a better chemical bond with the matrix resin, and the interfacial shear strength is about 14% higher than that of the KOH-treated carbon fiber composite.