Preparation And Research Of Thermal Insulation Foamed Material By Modified Urea-formaldehyde/Cement

In our country energy structure, building walls energy consumption accountsfor about23%~24%of total energy consumption, so it has a great significance tovigorously promote the use of building walls thermal insulation materials. But,building walls thermal insulation materials recently used are mainly flammableorganic insulation materials, which threaten people’s life and property safety. Basedon its fatal situation, it is necessary to develop a new type of incombustible buildingwalls thermal insulation materials.From the perspective of incombustible, A-class incombustible inorganiccement foam insulation materials firstly prepared through the method of premixedat room temperature. Studied the ratio of water to material and the best dosage ofcoagulant and fly ash, it concluded that the quality of cement foamed board wasbetter and the diameter of bubble hole was uniform, with the ratio of water tomaterial0.525, coagulant7.0wt%and fly ash20.0wt%. Studied the optimal formulaof cement foamed board with better effect of foaming using the orthogonal test, itsbetter dosage of foaming agent, water repellent and surface-active agent wasrespectively7.5wt%,1.25wt%,2.5wt%. Cement foamed board was prepared withcompressive strength0.24MPa, ductility0.80%, thermal conductivity0.0552W/m·K and water absorption45.3%. The test results revealed that its mechanicalproperties and heat insulation performance were poor and needed to be improved.The excellent flame retardant performance, low price of urea-formaldehyderesin was chosen as organic toughening materials of cement foamed board. For itshigher bibulous rate and bigger brittleness shortcomings, melamine and PVA（Polyvinyl alcohol）were used to improve the performance of urea-formaldehyderesin. The modified urea-formaldehyde resin was achieved with viscosity294.6mPa·s, bibulous rate9.75%, free formaldehyde content0.225%, compressionstrength7.8MPa, solid content48.6%and ductility0.54%. Compared tourea-formaldehyde resin, the modified urea-formaldehyde resin’s compressionstrength increased32.2%, water absorption decreased55.3%., and its brittlenesswas greatly improved. Cement composite foamed board was prepared by using cement and a new typeof modified urea-formaldehyde resin with low water absorption and low brittleness.Different dosage of modified resin’s influence to composite foamed boardproperties was studied. The experiment results showed that composite foamed boardwith30wt%modified urea-formaldehyde compressive strength increased to0.47MPa, ductility increased to1.62%and the thermal conductivity decreased to0.0352W/m·K. Compared to cement foamed board, the mechanical properties and thermalinsulation performance of composite foamed board were largely improved. Whilethe incombustible test results showed that composite foamed board was also A-classincombustible building wall thermal insulation materials.Vitrified beads were chosen to reinforce cement composite foamed insulationboard, which was found greatly improved cement composite foamed insulationboard’s mechanical properties. The vitrified beads-reinforced cement compositefoamed board was prepared by added30wt%modified resin and5wt%Vitrifiedbeads with compressive strength1.23MPa, ductility1.23%, thermal conductivity0.0336W/m·K and bulk density367.0kg/m3. Compared to cement foamed board,the compression strength of composite foamed board was more than its5times. Atthe same time, thermal conductivity and brittleness respectively decreased39.1%,50.0%. The vitrified beads-reinforced composite foamed board was also A-classincombustible building wall thermal insulation materials.