Thermo‐Mechanical Analysis of Epoxy Resins Under the Influence of Moisture‐Heat Coupling by Molecular Dynamics Simulation

Abstract

AbstractEpoxy resins are used in electronic packaging. However, its low thermal conductivity is a disadvantage and the high moisture absorption leads to defects such as cracking and delamination. In this work, the effect of thermo‐mechanical properties of epoxy resins under moisture‐heat coupling is investigated by molecular dynamics (MD) simulations. The diglycidyl ether of bisphenol A (DGEBA) and polyetheramine D230 are used as epoxy resin matrix and curing agents, respectively. The degree of cross–linking is set from 0% to 98% and the moisture mass fraction is set from 0 wt.% to 10 wt.%. The radius distribution function(RDF) shows that water molecules tend to appear ≈2.75 Å from the epoxy resin. The thermal conductivity of the epoxy resin increases by 54.55% for the maximum cross–linking degrees studied. And it increases by 19.23% when the moisture mass fraction is increased from 0 wt.% to 10 wt.%. The deformation of the epoxy resin is calculated which includes the coefficient of thermal expansion(CTE), coefficient of moisture expansion(CME), and coefficient of linear expansion. It is found that moisture expansion predominated at low temperatures and thermal expansion dominates at high temperatures. The analysis provides a theoretical basis for the study of hygrothermal coupling effects.