To gain better interfacial and mechanical performances of carbon ber reinforced epoxy resin (CF/EP) composites, the surface modi cation of CF was carried out via a simple mild method. The polydopamine (PDA) was applied to size the CF, as well as the in uence of PDA sizing time on CF were elucidated. As the PDA deposited time increases, a growing number of PDA nanoparticles were adhered on CF surface, associating with appearance of PDA agglomerates. Through analyzing the results, the optimum PDA sized time was 24 h. The introduction of PDA increase the chemical reaction and mechanical interlocking between ber and matrix. Compared with unsized CF, the tensile strength of PDA 24 h sized CF was improved by 27.0%, the interlaminar shear strength, exural and impact strength of PDA 24 h sized CF/EP composites increased by 103.7%, 65.6% and 163.6%, respectively. Furthermore, the fracture topographies of CF/EP composite strikingly implied that the PDA has a positive impact on the mechanical performances of CF/EP composites.

To gain better interfacial and mechanical performances of carbon fiber reinforced epoxy resin (CF/EP) composites, the surface modification of CF was carried out via a simple mild method. The polydopamine (PDA) was applied to size the CF, as well as the influence of PDA sizing time on CF were elucidated. As the PDA deposited time increases, a growing number of PDA nanoparticles were adhered on CF surface, associating with appearance of PDA agglomerates. Through analyzing the results, the optimum PDA sized time was 24 h. The introduction of PDA increase the chemical reaction and mechanical interlocking between fiber and matrix. Compared with unsized CF, the tensile strength of PDA 24 h sized CF was improved by 27.0%, the interlaminar shear strength, flexural and impact strength of PDA 24 h sized CF/EP composites increased by 103.7%, 65.6% and 163.6%, respectively. Furthermore, the fracture topographies of CF/EP composite strikingly implied that the PDA has a positive impact on the mechanical performances of CF/EP composites.