Injection-Compression-Compression Process for Preparation of High-Performance Conductive Polymeric Composites

Injection-compression-compression (I-C-C) process was studied to prepare polypropylene/ short carbon fiber (PP/SCF) composites. The effects of I-C-C process on the conductive network, fiber distribution and electric conductivity were investigated. The distance between conductive particles of the blending system was reduced by two-stage compression, so that the conductive network was compacted. The forming of dense conductive network significantly improved the conductivity. Moreover, I-C-C can effectively interfere with the fiber flow direction to enhance the conductivity of the infiltrated surface. Combined with the microstructure and electrical conductivity, the applicable mold temperature and compression speed range of the I-C-C process for PP can be obtained. The results showed that the electrical conductivity of the I-C-C prepared PP/SCF was increased up to 5 orders of magnitude higher than that of ordinary injection molding. Conductivity of PP/ 10wt% SCF conductivity reached 3.7S/m, PP /15wt% SCF reached 33S/m, and PP/ 20% SCF reached 150S/m.