Recent advances of interfacial modifications toward carbon fiber‐reinforced thermoplastic polypropylene and polyamide composites

Abstract The performance of carbon fiber‐reinforced thermoplastic composites (CFRTP) has been restricted by the performance of the interface. In general, the interfacial properties of CFRTP are determined by both the surface properties of the carbon fiber (CF) reinforcement and the infiltration properties of the thermoplastic matrices, which possess high melt viscosity and seem difficult to sufficiently infiltrate the fiber reinforcement. As a result, the melt flow characteristics of different matrices significantly influence the interfacial melt penetration and mechanical properties of CFRTP. In this paper, in order to explore the influence of melt flow characteristics of various thermoplastic resins toward CFRTP interfacial behaviors, high‐polarity polyamide (PA) and low‐polarity polypropylene (PP) resins are selected as representative resin matrices among commonly used resin systems. Specifically, the polarity differences and interface‐forming mechanisms of CFRTP are first established. Following a systematical discourse on the latest research progress of interfacial modifications in PP/PA‐based CFRTP are described, centering on the effects of various modification methods on improving the interlaminar/interfacial strength, toughness, impact strength, and bending strength of the composites. In addition, this paper also classifies the interfacial mechanisms of CFRTP in terms of interface bonding, interface strengthening, and interface failure. Finally, the shortcomings and future research directions are pointed out to achieve effective interfacial construction and innovative modification of CFRTP. Highlights An introduction of resin polarity differences of CFRTP is established. An introduction of interface‐forming mechanisms of CFRTP is established. State‐of‐art characterization techniques of CFRPs interface are provided. Effect of melt flow property on the interfacial behavior of CFRTP was explored. The interfacial mechanisms are systematically analyzed.