Effect of interfacial modification on metal fiber filled polypropylene composites and property balance

Abstract Mechanical properties and electrical conductivity of discontinuous stainless steel fiber (SSF) filled polypropylene (PP) composites were considered as candidates for shielding electromagnetic interference (EMI) applications. In order to improve the unsatisfied impact resistance, surface treatments of SSF and modified PP were introduced. By means of a microdroplet pull‐out test, polypropylene grafted maleic anhydride copolymer (PP‐g‐MAH) was found to be able to enhance the poor interfacial adhesion between fiber and matrix. On this basis, PP‐g‐MAH was used to prepare conventional composites, and the macromechanical measurements showed evidence that PP‐g‐MAH helped increase both flexural and impact strength of the composites. However, the good affinity of PP‐g‐MAH for SSF reduced composite conductivity accordingly. Finally, blends of PP and PP‐g‐MAH proved to be a solution for the problem, i.e., the impact strength was increased significantly while acceptable electrical resistivity was maintained.