Preparation of Ionic Liquid Modified Graphene and Its Influence on the Properties of PP Conductive Composites

To improve the dispersion of graphene in polypropylene (PP) and enhance the mechanical and electrical properties of PP‐based composites, a silicon‐containing ionic liquid, 1‐hexyl‐3‐trimethylsilylmethylimidazolium tetrafluoroborate ([HTMSiIm]BF 4 ), was synthesized and used to functionalize carbon fillers. Expanded graphite (EG), flake graphite (FG), and carbon nanotubes (CNTs) were modified via ultrasonic‐assisted treatment to obtain ionic liquid‐functionalized fillers (G@IL), which were subsequently incorporated into PP through melt blending to fabricate G@IL/PP composites. Structural characterization confirmed that graphene was functionalized through cation–π interactions without disrupting its intrinsic structure. The introduction of the ionic liquid significantly improved the interfacial compatibility between graphene and the PP matrix. At a G@IL loading of 10 wt%, the tensile strength and flexural modulus of the composite reached 25.1 and 1356.5 MPa, representing increases of 24.17% and 27.48%, respectively, compared with neat PP. In addition, the electrical conductivity increased to 1.954 × 10 −7 S/cm, which was approximately 11 orders of magnitude higher than that of pure PP and higher than that of the unmodified G/PP composite.