Mechanical Properties Of Epoxy Resin Composites In Hot And Humid Environment

As packaging materials,coatings and cross-linking agent,epoxy resin is widely used in national defense and various fields of civilian industries,it’s thermodynamic properties will be influenced significantly in hot and humid environment,So silica powder and other fillers are often used to improve the properties of epoxy resin in real productions.The improvement effect of silicon powder on the properties of epoxy resin has important research and application value.In this paper,the atomic model of epoxy resin and fused silica powder is constructed by Material Studio,the mechanical parameters of epoxy resin and fused silica powder under different temperature and moisture content are obtained by means of molecular dynamics simulations(MD),and the moisture-heat expansion coefficient as well;On this basis,the mechanical properties of epoxy resin / silica powder composites were studied by generalized self consistent method(GSCM),and the thermal expansion coefficient of epoxy resin composites was calculated by using the theory of micro-mechanics;Thereafter,the representative volume elements of epoxy resin and silica powder composite materials are constructed.The mechanical parameters and moisture-heat expansion coefficient of the composite materials are obtained through finite element simulations,and the results under different approaches are compared.In addition,the molecular dynamics method is used to study the epoxy resin and crystalline silicon dioxide interface,the molecular dynamics model of epoxy resin / crystalline silicon dioxide interface is constructed,and the interaction energy of the interface under different heat and moisture conditions was simulated.The results show that: the mechanical properties of epoxy resin and it’s composites are dwindled in hot-humid environment,the mechanical properties of epoxy resin can be improved significantly by filling with silica powder.The moisture-heat expansion coefficient of epoxy resin decreases with the increase of the content of silicon powder;The interaction energy and bond strength between epoxy resin and crystalline silicon dioxide is decreased with the increase of temperature or moisture content,therefore,the strength of the epoxy resin/ crystalline silicon dioxide composite is affected.