Surface Modification of Graphene Nanoplatelets (GNP) Towards Preparation of Natural/Synthetic Rubber Blend Nanocomposites

Abstract

Graphene nanoplatelets (GNP), newly discovered nanomaterial, act as a great potential and promising candidate in various technological applications. Nevertheless, the direct use of GNP is restricted owing to its incompatibe surface properties. This study focuses on the interaction between GNP filler with the rubber blend matrices and their correlation to the resulted properties. The surface modifications on GNP were carried out by applying a covalent and non-covalent approaches using aminopropyltryetoxysilaned (ATPS) and poly(ethyleneimine) (PEI), respectively. The unmodified, ATPS- and PEI-modified GNP were then compounded with natural rubber/ethylene–propylene–diene–monomer (NR/EPDM) at various filler loadings, and the cure characteristics and mechanical of nanocomposites were investigated. The success of the surface modifications was examined and performed through the Raman and FTIR spectroscopy analysis, and FESEM observation. Compared to unmodified GNP, the addition of ATPS-modified GNP into NR/EDPM blend improved blend processability the most, followed by PEI-modified GNP as the cure characteristics results showed the increase in CRI and both MH and ML torque, but declined in Ts2, tc90, MH-ML. For unmodified GNP, the maximum GNP loading at 3.00 wt.% doubled increased the tensile strength compared to the unfilled blend, and Shore A hardness value linearly increased with the GNP loading. Both modified GNP filled rubber blend nanocomposites further improved the tensile strength and stiffness at 300% elongation. GNPs-APTS-treated nanocomposite is able to provide a maximum synergistic effect of improved mechanical properties and thermal durability which is beneficial for the suggested application of rubber component in an automotive engine mount.