| With the progress of science and technology,the materials integrate structure function are putted forward in national defense industry and national economic development.The study of composite materials with light weight,high strength and thermal insulation are going to be the focus to domestic and overseas scientists.The materials with light weight,high strength and thermal insulation are used widely in aerospace materials,Deep sea solid buoyancy materials,fan turbine blade,and so on.The design idea of this study is the integration of structure and function.The advanced composite materials of low thermal conductivity,low density and high strength were made in the condition of structure design,material system design and heat isolation design,which promote the development of material science.The spherical shell filling of epoxy resin matrix composites were prepared by vacuum pouring process using low viscosity epoxy resin as matrix,methyl tetrahydrophthalic anhydride and 2-ethyl-4-methyl imidazole as composite curing agent and hollow spherical shells as lightweight filler.The influence rule of defferent curing systerm,spherial shell diameter,thickness and fiber content of spherial shell to the spherical shell filling of epoxy resin matrix composites'material mechanics properties and heat isolating property were studies.The compression damage behavior and thermal isulation mechainism of the spherical shell filling of epoxy resin matrix composites were studied furture.The research results show that the density of the spherical shell filling of epoxy resin matrix composites,compression strength are incresing with the increase of curing agent,thickness and fiber content of spherial shell,are decresing with the diametric of spherial shell,the leading infuluence of the spherical shell filling of epoxy resin matrix composites'performance is the diametric of spherial shell.The specific strength can reach maximum value of 67.139kPa.m~3/kg,density of 0.599g/cm~3and compression strength of 40.185MPa when the dosage of curing agent is 49%,spherical shell diameters 10 mm,spherical shell thickness is0.44mm and fiber content is 45%.The thermal conductivity is increasing with the increase of thickness and fiber content of spherial shell,is decreasing with the increase of spherical shell diameter,the minimum thermal conductivity is 0.1206W/(m·K),density is 0.475g/cm~3,compression strength is 21.660MPa,specific strength is 45.650kPa.m~3/kg when the spherical shell diameter is 10mm,spherical shell thickness is 0.36mm,fiber content is 45%.The spherical shell diameters crucial factor from anayzing the influence factors of material mechanics properties and thermal property.The density is lower,the heat insulation property is better,the strengh is lower when the spherical shell diameter is bigger.According to the analyse of compression damage behavior,the stress is focus between spherical shell and epoxy resin matrix when the spherical shell filling of epoxy resin matrix composites are loaded by uniaxial press.The spherical shell is compressive deformation and appears microcrack,the main crack extend unstablely follow hook face,there are cracks among pore defective part in spherical shell filled with epoxy resin matrix composites matrix,and these cracks extened all the time,and finally the spherical shell filling of epoxy resin matrix composites are collapse.The spherical shell diameter is the leading influence factor to the thermal conductivity to composites from the theoretical analysis and experimental measurement.The heat insulation mechanism is that the air volume is bigger with the largen of the spherical shell diameter,the thermal conductivity of air is much lower than that of composites,which lead to the high heat insulating property of composites,meantime,the number of spherical shells in unit volume composite is decreasing for the increase of the spherical shell diameter,the total surface area of shell thickness and the interior heat conduction pathes are decreasing,which is good for the improve of heat insulation,the study of the influence of shell material and fiber content to thermal conductivity shows that the heat insulation performance is reduced with the increase of spherical shell thickness because of the thermal conductivity of spherical shell materials is higher than that of the air in the spherical shell,which improve the ability of heat conduction.The heat insulation performance is reduced with the increase of fiber content owing to the thermal conductivity of fiber material is higher than that of resin matrix which improve the heat conduction ability. |
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