Study On Thermal-mechanical Properties Ofepoxy Resin Based Insulation Materials

With the rapid growth of China's national economy,the problem of energy shortage is becoming increasingly serious.In various industries,building is the largest energy consumption in China,building energy saving plays a vital role in reducing energy consumption in China.Building energy conservation is the focus of energy conservation and emission reduction.External wall insulation is an important part of building energy conservation,and thermal insulation materials are the important foundation of wall insulation system.Epoxy resin matrix composites with epoxy resin(EP)as matrix and hollow glass microspheres(HGM)as filler have high specific strength and stiffness,low water absorption,low thermal conductivity,high thermal stability and corrosion resistance.In the construction industry,hollow glass microspheres/epoxy composite foam materials can be used for thermal insulation materials,high temperature laminated components and so on.Although they are rarely used in construction industry,with the rapid development of building insulation materials in China,the performance requirements of thermal insulation materials are getting higher and higher.HGM/EP Composites are characterized by light weight,high strength and good flame retardancy.It has a certain application prospect in the field of building thermal insulation.Thermal insulation materials are often affected by temperature in the service process.However,temperature has a great impact on the properties of epoxy resin matrix composites.Whether they can work normally at a certain temperature is not clear,and the related research is less.Therefore,the research on the compression properties,thermal conductivity and thermal conductivity of HGM/EP composites at different temperatures is very important Thermal expansion coefficient and other parameters have important research significance in the field of building insulation.In this paper,the epoxy resin composites with the highest 70%filling ratio were prepared by using bisphenol A epoxy resin as matrix and hollow glass microspheres as fillers.The influence of filling ratio of hollow glass microspheres on the density,compressive strength,thermal insulation property,thermal expansion property and water absorption rate of epoxy based composite foam materials was systematically analyzed.And the influence of temperature on the compressive properties of epoxy-based composite foam was discussed.The results show that the volume fraction of hollow glass microspheres increases from 0%to 70%,the density of HGM/EP composites decreases from 1.073g/cm3 to 0.665g/cm3,and the density of HGM/EP composites decreases by 38%.The water absorption of the composite increases with the increase of time,and the composite with high filling ratio has higher water absorption.When the filling ratio exceeds 10%,the water absorption of the composite increases greatly,and the composite with 70%filling ratio has the highest water absorption,reaching 3.65%at 768h.The quasi-static compression tests of HGM/EP composites at different temperatures show that temperature has little effect on the properties of hollow glass microspheres,and epoxy resin is the main factor affecting the compression properties of HGM/EP composites with different volume contents.According to the compression stress-strain curve and failure morphology,the failure mechanism of HGM/EP composites is analyzed,Three main compression failure modes were summarized,and the influence of temperature and filling ratio on the compression strength of HGM/EP composite was analyzed.The results show that the yield strength of pure resin decreases greatly with the increase of temperature,and the yield strength of HGM/EP composite increases with the increase of filling amount of hollow microspheres,The elastic modulus of HGM/EP composites increases at different temperatures.Based on the finite element software ANSYS,the influence of temperature and filling ratio on the compression performance of composite was simulated by using the single cell model,and the failure mechanism was analyzed from the micro level.It is found that the stress of the hollow microspheres is much greater than that of epoxy resin matrix,and the stress of the hollow microspheres is mainly concentrated near the equator,while the stress of the resin matrix is mainly concentrated in the middle and upper part of the wall,and the damage is mainly caused by the broken hollow microspheres.The two-dimensional random distribution model of composite was established by using ANSYS parametric language APDL.The influence of filling ratio on the thermal insulation and thermal expansion of epoxy resin matrix composites was analyzed.The thermal conductivity of the composite was predicted,and the thermal insulation and thermal expansion mechanism of epoxy resin based composite were analyzed.The results show that the thermal conductivity and expansion coefficient of the composite can be reduced by hollow glass microspheres as filler,the filling ratio increases from 0%to 70%,the thermal conductivity of epoxy resin matrix composites decreases by about 50%,and the thermal expansion coefficient decreases by 42%.The thermal conductivity of the composites with 50%and 70%filling ratio is lower than 0.14w/(m·K),which meets the requirements of thermal insulation materials.At 20?and 40?,the compressive strength of the composite with 50%filling ratio is the highest,which is 46.3mpa and 20.6mpa respectively;At 60? and 80?,the compressive strength of the composite with 70%filling ratio is the highest,but the compressive strength is lower,which is 6.8mpa and 4.3mpa respectively.The results show that the composite with 50%filling ratio has good thermal insulation performance,high compressive strength and best comprehensive performance at low temperature;When the temperature is high,the composite with 70%filling ratio has good thermal insulation performance,but the compressive strength is low,which is not ideal.