Graphene as an Interface Modulator for the Performance of Carbon Fiber Reinforced Polyolefin Composites

Rational regulation of the polyolefin/carbon fiber (CF) interface is crucial for maximizing the mechanical and functional properties of composites. Graphene has been widely employed as an interface modulator due to its high surface energy and flexibility, but optimizing interfacial compatibility among graphene, polyolefin, and CF remains challenging. Herein, three types of modified graphene (MGr)─chemical graphene oxide (CGO), electrochemical graphene oxide (EGO), and electrochemical graphene (EEG)─were prepared via specific chemical modification methods to enhance the interfacial strength between CF and linear low-density polyethylene (LLDPE). Incorporation of MGr@CF significantly improved the tensile strength (up to 35%), electrical conductivity (up to 2.1 × 10⁻² S·cm⁻¹), and thermal conductivity (up to 0.52 W·m⁻¹·K⁻¹) of LLDPE composites. Notably, EGO@CF exhibited the best mechanical performance, whereas EEG@CF provided superior electrical heating efficiency and electromagnetic interference (EMI) shielding. These results demonstrate that the type of MGr critically influences the multifunctional properties of the composites. This work provides a guideline for the rational design of high-performance CF-based polyolefin composites through controlled graphene modification.