Improved interfacial shear strength in polyphenylene sulfide/ carbon fiber composites via the carboxylic polyphenylene sulfide sizing agent

Abstract The carboxylic polyphenylene sulfide (PPS–COOH) with low molecular weight was synthesized and used as a part of sizing agent to improve the interfacial shear strength (IFSS) of polyphenylene sulfide/carbon fiber (PPS/CF) composites in this study. And the PPS-COOH sizing agent with good heat resistance was homogeneously coated on the carbon fiber surface, introducing the functional groups and causing the improvement of CF surface roughness. The mechanical properties were investigated through the tensile strength of composites and IFSS with the virgin carbon fiber (VCF), the plasma treated carbon fiber (PCF) and the modified carbon fiber coated by PPS-COOH sizing after plasma treatment (ACF). The tensile strength of ACF/PPS composites has enhanced to 115.20 MPa, which is also verified through the tensile fracture surfaces of composites. The IFSS experimented by microbond test suggests that the apparent interfacial shear strength (τapp) of ACF/PPS composites has increased to 37.19 MPa, which is 27.71% and 15.07% higher than VCF/PPS and PCF/PPS composites, respectively. Hence, it is the promising method to prepare and size the great heat resistant sizing agent on the plasma treated CF to effectively improve the interfacial shear strength of CF/PPS composites.