Synthesis, mechanical, and barrier properties of LDPE/graphene nanocomposites using vinyl triethoxysilane as a coupling agent

Precise interface control and dispersal of graphene nanosheets in polymer hosts are challenging to develop high performance graphene-based nanocomposites due to their strong interlayer cohesive energy and surface inertia. Here, we firstly report an efficient and novel method to functionalize graphene nanosheets with vinyl triethoxysilane (VTES) and successfully blend them with low density polyethylene (LDPE) to prepare nanocomposites. Fourier transforms infrared spectra (FTIR), Raman spectra, and thermogravimetric analysis (TGA) proved that the graphene sheets were covalently bonded with VTES. The resulting nanocomposites obtained the increases of up to 27.0 and 92.8% in the tensile strength and Young's modulus, respectively, compared to neat LDPE. The VTES-graphene not only remarkably improved the tensile strength of the composites, but also enhanced its toughness by 17.7%. Oil permeability measurements showed that the absorption ratio of toluene by the LDPE/graphene composites decreased from 56 to 39%, and its barrier properties have obviously been improved. This study opens a new route to optimize interface structures and improve the comprehensive performances of graphene-polymer nanocomposites.