Exterior Insulation Material Of Polymer Modified Magnesium Cement System

Using ethylene vinyl acetate （EVA） emulsion, and chopped fibers ofpolyacrylonitrile （PAN） modify magnesia cement system to prepare exteriorinsulation material. The exterior insulation material has a A-level fire-retardantproperty, low thermal conductivity, good mechanical properties. Through exploringthe curing temperature of the hardening process of cementitious materials, humidity,curing time, optimize the test conditions for the crystallization properties andmechanical properties of cementitious materials. Explore how the density, watercontent effect thermal conductivity of the insulation material, meanwhile fit the curveso as to provide a reference for the application of the insulation material. Studythermal conductivity of the multilayer composite by theoretical derivation andcalculation to provide a theoretical basis for the multi-layer composite insulationmaterial.When the curing temperature is30℃, meanwhile the temperature of the systemis between40⁶0℃, the humidity control more than65%and the demolding timecontrol5⁷d, curing time control in the28d, in this case, the mechanical andcrystalline properties of materials can reach the best. Controlling the amount of EVAand PAN in the material reasonably, the tensile strength of the thermal insulationmaterial can reach more than0.1MPa, compressive strength higher than0.5MPa, A-level fire retardant, wherein the heat value less than2MJ/kg, burning time0s,temperature rise less than30℃, the mass loss of less than50%.Through simulating the connection between density and thermal conductivitypreparation material data between, the correlation coefficient R-Square is0.992,close to1. A linear change between the density and the thermal conductivitycoefficient can be approximated as y=0.218x+0.018, Wherein y is the thermalconductivity, x is the density. Simulating the relationship between the moisturecontent and thermal conductivity coefficient, the correlation coefficient of0.998,highly correlated. The influence of water content on the thermal conductivity can beexpressed as y=5.36×10^-4x³-4.03×10^-6x²+3.61×10^-6x+0.057, Wherein y represents thethermal conductivity of the material, x represents the moisture content of the material.Through analysis and derivation of the factors affecting the thermal conductivityof the two-layer composite insulation materials, The following theoretical formula canbe deduced:λ=λ₂（（λ₁-λ₂）/λ₂+λ₁）+λ₂, Where λ₁and λ₂are the respective thermal21 conductivity of material1and material2, x is the thickness ratio, λ is the thermalconductivity of the composite material.