PREDICTION OF MOLECULAR INTERACTIONS AND INTERFACIAL BONDING OF NANOTUBE/EPOXY COMPOSITES USING MOLECULAR DYNAMICS SIMULATION

摘要

Unlike in conventional carbon fiber composites, intensive molecular interactions are expected during processing and at the interphase of single-walled nanotubes (SWNTs)/epoxy composites due to SWNTs' small diameters, extra-large surface areas and unique chemical characteristics. Consequently, these interactions are crucial for resin matrix selection to create strong interfacial bonding in SWNT/polymer composites. In this study, molecular dynamics (MD) simulations reveal the molecular interactions between (10, 10) SWNTs and Epon 862 resin/EPI-CURE W curing agent molecules before the resin curing. A three-dimensional cross-link model of the cured resin was established for MD simulation of a single SWNT pullout to predict the interfacial bonding of the resultant composites. The simulation results indicate that both Epon 862 and EPI-CURE W curing agent molecules have strong attractive interactions with the SWNTs, and their molecules have a tendency to stretch and wrap around the SWNT surfaces. Simulations show good wetting can be expected between SWNTs and Epon 862 matrix. The molecular interaction energy during single nanotube pullout from resin cross-link network was calculated using the MD simulation of a simplified SWNT pullout model, and the interfacial shear strength between SWNT/Epon 862 matrix was predicted. The MD simulation results agree with the preliminary experimental observations.