Injection molding of segregated carbon nanotube/polypropylene composite with enhanced electromagnetic interference shielding and mechanical performance

摘要

The formation of segregated structure in conductive polymer composites reveals great superiority in gaining improved electromagnetic interference (EMI) shielding performance. Nevertheless, the restricted processing method and seriously deteriorated mechanical properties hamper the practical applications of such segregated composites. Herein, we demonstrate simultaneously improved EMI shielding and mechanical performance in a segregated carbon nanotube/polypropylene (CNT/PP) composite, via a facile and eco-friendly method composed by pre-coating, melt mixing, and injection molding. The segregated CNT/PP composite containing only 3.5 wt% CNT exhibits an average EMI shielding effectiveness (EMI SE) of 32 dB, which shows 130% and 30% improvements in comparison to 14 dB for the CNT/PP composite prepared by conventionally injection molding and 25 dB for the CNT/PP composite prepared by compression molding. Our segregated CNT/PP composite also attains a high elongation at break (EB) of 78%, about 4 and 17 times higher than 16% for the conventionally injection molded one and 4% for the compression molded one, with comparable tensile strength and Young's modulus. This work provides a feasible approach to guide the scaled preparation of segregated composites with satisfactory EMI shielding and mechanical performance.