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

Mechanical properties and electrical conductivity of discontinuous stainles s 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 o f 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 matr ix. On this basis, PP-g-MAH was used to prepare conventional composites, an d the macromechanical measurements showed evidence that PP-g-MAH helped inc rease both flexural and impact strength of the composites. However, the goo d 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 ele ctrical resistivity was maintained.