Microscale investigation on the carbon fiber surface physical properties and interfacial behavior of carbon fiber/polypropylene composites fabricated by self‐resistance electric heating technique

Abstract In this study, the interfacial bonding properties of carbon fiber/polypropylene (CF/PP) composites fabricated by self‐resistance electric (SRE) heating technique was investigated by both experimental trials and molecular dynamic (MD) simulations. The temperature distribution and the changes in surface physical properties of CFs with SRE heating were firstly determined by experimental investigations. The experimental results suggest that the amount of grooves on CFs surface is positively related to electric current magnitude, while the height of grooves is negatively associated to electric current magnitude. The microbond test was carried out to determine the interfacial shear strength (IFSS) of CF/PP composites. It demonstrates that the IFSS increases from 31.00 to 39.11 MPa when CFs is applied with electric current from 12 A to 20 A, which is same with the trend of the surface area of CF. Moreover, the mechanisms of interfacial adhesion enhanced by surface morphology of CF were investigated by MD simulations. CF models with different surface morphology were constructed based on the experimental results. It is found that the increase of the contact area between CF atoms and PP atoms benefits the interfacial adhesion. Meanwhile, the gradual loss of the ability of matrix impregnation accompanies with the strengthening of interfacial interaction, leading to a weak increase in the shear strength between CF and matrix.