Molecular simulation of the effects of water on the interface of plant fiber/polyvinyl alcohol (PVA) composites prepared by dry preparation method (DPM)

Abstract

The preparation of a composite material based on plant fiber that contains water and polyvinyl alcohol (PVA) powder was analyzed by molecular dynamic simulations. The results show that water migration from cellulose under specific temperature and pressure conditions is influenced by its hydrogen bonding with different components. Water strongly hydrogen bonded to plant fiber migrates with difficulty, whereas weakly hydrogen bonded water migrates to the interfacial layer to form stable hydrogen bonded bridges. Water molecules not captured by the interfacial layer migrate to the PVA phase and form new hydrogen bonds that have a plasticizing effect for PVA. The plasticized PVA can better coat the plant fiber, forming more hydrogen bonds between PVA and plant fiber. Hydrogen bonding bridges formed by water at the interface strengthen the interfacial bonding. Simulation and experimental results show that PVA with a lower molecular weight has stronger interfacial binding strength with the plant fiber, giving a higher modulus. The appropriate plant fiber water content achieves the optimal composite mechanical properties. Water has a significant role in the interfacial enhancement of plant fiber/PVA composite materials prepared by the dry preparation method.