Insight into glass transition temperature and mechanical properties of PVA/TRIS functionalized graphene oxide composites by molecular dynamics simulation

Abstract

Mechanical properties of polyvinyl alcohol (PVA) are of essential importance to the practical application. Much effort has been done to further improve the properties of PVA by modifiers. However, in-depth insight into the role of the modifiers in the properties of PVA at a molecular level still remains rare. Therefore, the Glass transition temperature (Tg) and mechanical properties of PVA, PVA/graphene oxide (GO) and PVA/TRIS functionalized graphene oxide (Tris-GO) are investigated by molecular dynamics (MD) simulation. The results indicate the volume of PVA, PVA/GO and PVA/Tris-GO regularly varies with temperature. The PVA/Tris-GO show a higher Tg compared to the PVA/GO owing to stronger hydrogen-bonding interactions. The Young’s modulus, Shear modulus and Cauchy pressure of PLA/Tris-GO nanocomposites are enhanced by 50%, 46%, and 40% at 2.5 wt% addition amount of Tris-GO. In addition, the introduction of Tris-GO can significantly reduce the mobility and flexibility of the PVA chains in the PVA/Tris-GO. The binding energy between PVA and Tris-GO is larger than that between PVA and GO, which leads to the improved mechanical properties of the PVA/Tris-GO. These simulation results provide a better understanding of the thermomechanical mechanism of PVA/Tris-GO nanocomposites, and an effective guidance for improving their mechanical properties.