Mold-opening foam injection molded strong PP/CF foams with high EMI shielding performance

Abstract

As one of the most widely used thermoplastics, polypropylene (PP) owns the poor foaming ability, resulting in the large and severely deformed cells in the foams fabricated by the regular foam injection molding (RFIM) process. Thus, carbon fiber (CF) was introduced to enhance the crystallization ability and melt viscoelasticity when using the mold-open foam injection molding (MOFIM) process. Under the dual functions of CF and MOFIM technology, the pronounced refined cell size and high cell density were successfully prepared. Thanks to the dense foam structure, the tensile strength and modulus of PP/CF composites prepared by MOFIM technology were respectively enhanced by 79.7% and 172.6% compared with that of RFIM-fabricated PP foam. Moreover, the reconstruction data of Micro-CT demonstrated that the fiber distribution uniformity induced by MOFIM technology was improved, which strengthen the electrical conductivity and EMI properties, achieving 35.78 dB with the presence of 20%CF.

Keywords

• PP/CF composites
• Foaming
• EMI shielding Properties
• CF reconstruction