Molecular Dynamics Simulations of DGEBA/OSC Epoxy Composites for Improving Heat-Resistance and Elastic Modulus

Abstract

Thermal and mechanical properties of DGEBA/OSC epoxy composite polymers composed of both bisphenol A diglygde ether (DGEBA) and alicyclic epoxy resin (OSC) as co-polymerization monomers and 3,3-diaminodiphenyl sulfone (DDS) as curing agent are evaluated and investigated by molecular dynamics (MD) simulations, in which NPT ensembles and annealing cycles in a wide temperature range are utilized for modeling the thermodynamic equilibrium systems and heating processes. Glass transition and thermal-decomposition temperatures are calculated by linear fitting on the temperature dependence of elastic modulus, cohesive energy, fractional free-volume (FFV). It is verified that the two DGEBA/OSC epoxy composite can effectively improve the thermal and mechanical performances of epoxy polymer, in which DGEBA/OSC(1:1) epoxy composite are most significant of promoting mechanical stiffness and render a elevated glass transition temperature by 28 K and thermal-decomposition temperatures by 91 K, the two DGEBA/OSC epoxy composite are capable of efficiently reduce fractional free volume by 4.4% and 8.6% for DGEBA/OSC(3:1) and DGEBA/OSC(1:1) epoxy composite respectively, which is in consistent with the lower rotation amplitudes of crosslinking bonds for DGEBA/OSC composite EP polymers that vdW interaction forces between molecular-chains can be promoted by OSC co-polymeric blocks to inhibit thermal motions of EP molecular-chains.