Fabrication of polypropylene/carbon fiber/carbon black composite foam bonded with continuous carbon fiber reinforced polypropylene prepregs via high-pressure foam injection molding

The fabrication of polymer composite foams with several functions offers various advantages. Herein, we reported a highly efficient and mass-produced method for preparing polypropylene/carbon fiber/carbon black (PP/CF/CB) composite foams bonded with continuous CF reinforced PP prepregs. CFs were uniformly dispersed in PP via melt blending, but some agglomerations of CBs were observed owing to their little size. Compared with pure PP, the introduction of CB improved the thermal stability and flame retardance of composites. Owing to the homogeneity of polymer between composites and prepregs, they were well bonded by injection molding. The tensile strength of the samples bonded with prepregs was improved by 158.3–257.7 % for different filler contents. As CF and CB played the role of heterogeneous nucleation, and the high-pressure foam injection molding could easily tailor cellular structure by adjusting the holding time and mold temperature, composite foams bonded with two prepregs and with desired cells were successfully prepared. The injected foams with two prepregs had an enhanced electromagnetic interference shielding performance, which was 65.4 dB when the content was 10 wt% and 15 wt% for CF and CB, respectively. This work provides a universal approach for efficient and large-scale preparation of lightweight and multifunctional polymer composite foams.