Cost-Effective Fabrication of High-Density Polyethylene/Graphene Nanocomposites by an In Situ Exfoliation Method Based on a Series Explosion Effect

Abstract

As ideal nanofillers, graphene nanosheets (GNS) are widely used to prepare high-performance graphene-reinforced nanocomposites owing to their excellent properties. However, the high manufacturing cost and low production efficiency of GNS severely restrict their large-scale application. Herein, a cost-effective melt blending approach was demonstrated for facilely preparing high-density polyethylene (HDPE)/GNS nanocomposites by using industrial-grade expanded graphite (EG). The exfoliation and dispersion of GNS in the matrix under different processing temperatures and times have been studied. A series explosion effect generated by the synergy of volumetric extensional rheology and free water can violently and fastly exfoliate pristine EG into few-layer GNS. The in situ exfoliation mechanism revealed that the synergistic effect of the explosive forces of free water and the adhesion between HDPE and GNS can destroy the van der Waals forces between the EG sheets during melt blending, thereby realizing ultrafast exfoliation and uniform dispersion of EG in the HDPE matrix. As expected, the HDPE/GNS nanocomposites showed high crystallinity, excellent thermal conductivity, high dielectric constant, and extremely low dielectric loss. This work provides a new idea for facilely fabricating high-performance polymer-based two-dimensional layered nanocomposites.