Effects of Surface Modification on the Dispersion Property of VGC

Abstract

AbstractIn view of the easy agglomeration issue of vapor grown carbon fiber (VGCF) and the poor interfacial adhesion between VGCF and matrix resin, two‐step surface modification with hydrogen peroxide and concentrated nitric acid was performed on VGCF. The surface structure and dispersion of VGCF before and after modification were tested and analyzed by XRD, TGA, FTIR, UV‐visible spectrum and SEM. Moreover, VGCF/SMPU composites were prepared via a solution mixing method taking shape memory polyurethane (SMPU) as matrix, and the mechanical properties of the composites were also tested. The graphite crystal structure of VGCF showed very little change after modification, the concentration of oxygen‐containing functional groups on the surface of VGCF was visibly increased, and the dispersion and dispersion stability of VGCF in organic solvent were also clearly improved. In the cross section of the VGCF/SMPU composites, the dispersion of VGCF in matrix and the VGCF‐matrix interfacial adhesion observed through SEM were both enhanced to a certain extent after surface modification. The two‐step surface modified VGCF had more obvious mechanical reinforcement effects on the composites than that of the pristine VGCF.