It has been experimentally shown that epoxide-terminated hyperbranched polyether sulphone(EHBPES) can significantly improve the mechanical properties of traditional diglycidyl ether of bisphenol A/triethylenetetramine(DGEBA/TETA) systems,but the origin of the improvement is still unclear.In this work,we used molecular dynamics(MD) simulations to gain a thorough understanding of the origin of modulus improvement for EHBPES/DGEBA/TETA systems.It is found that the modulus of EHBPES/DGEBA/TETA systems increases with the increase of EHBPES loading.In addition,the crosslinking density,cohesive energy density(CED),and free volume can be used to understand the modulus for EHBPES/DGEBA/TETA systems.It is shown that the highest modulus is achieved at7 wt% EHBPES loading due to the highest crosslinking density and CED.When EHBPES loading is below 7 wt%,the higher CED and crosslinking density are responsible for the higher modulus.At higher loadings(> 7 wt%),the decreased modulus is closely related to the decreased crosslinking density and increased fractional free volume.It is expected that our results could be of great implications for designing high-performance epoxy materials.
Xue-Pei MiaoDao-Jian ChengYa-Dong DaiYan MengXiao-Yu Li
