A water-soluble PAAs sizing agent for enhancing interfacial adhesion of carbon fiber reinforced polyphenylene sulfide composites (CF/PPS)

Due to low activity and poor wettability of carbon fiber (CF), the interaction between CF and polyphenylene sulfide (PPS) matrix is weak, which decreases the mechanical properties of CF reinforced PPS (CF/PPS? composites. In this article, the interfacial adhesion of CF/PPS composites was strengthened by using a water-soluble poly (amic acid) ammonium salt (PAAs) as sizing agent. This PAAs-based sizing agent had good compatibility with PPS and formed hydrogen bonds with CF activated by Meldrum's acid. Significantly, the PAAs sizing agent can be soluble in water (up to 20 wt % high solid content) without organic solvents and surfactants, which shows huge potential in industrial applications. Experimental results demonstrated that the interlaminar shear strength (ILSS), flexural strengths, and moduli of modified CF/PPS composites increased by 19.5%, 24.9%, and 10.1%, respectively. According to the SEM images on fractured surfaces of composites, fiber and PPS resin were tightly packed, and the failure mechanism was interface deformation or resin breakage.