Effect of Noncovalent Bonding Modified Graphene on Thermal Conductivity of Graphene/Natural Rubber Composites Based on Molecular Dynamics Approach

Owing to its exceptional thermal conductivity, graphene demonstrates significant potential for enhancing heat transfer in rubber composites. However, the practical implementation of this application is substantially limited by interfacial thermal resistance at graphene-rubber interfaces. This study systematically investigates interfacial thermal transport characteristics in rubber composites containing four types of noncovalently modified graphene sheets (1-pyrenebutyl, 1-pyrenebutylamine, polybutyl acrylate, and polydopamine functionalized) through molecular dynamics simulations. Experimental results reveal that noncovalent modification substantially enhances composite thermal performance, with respective thermal conductivity improvements of 118.25%, 69.86%, 183.66%, and 81.54%, accompanied by interfacial thermal resistance reductions of 21.58%, 18.48%, 20.41%, and 17.63%. Phonon density of states analysis demonstrates that noncovalent functionalization enhances phonon spectrum matching between graphene and natural rubber. Notably, the phonon matching region stabilizes with an increasing functionalization degree, indicating the existence of an optimal modification level for maximizing phonon matching efficiency: a fundamental mechanism underlying the observed interfacial resistance reduction. Furthermore, noncovalent modification promotes superior dispersion homogeneity of graphene within the rubber matrix. These findings establish crucial theoretical foundations for developing high-performance, thermally conductive graphene/natural rubber composites.