Preparation Of Thermal Insulation Foamed Material By Modified Urea-formaldehyde/phosphate

Developing energy-saving materials has become a focus of the researchbecause of the current situation of the energy shortage. The proportion of buildingenergy consumption is about30%in the whole energy consumption. Consequently,the development of building energy-saving materials is an effective method toreduce the energy consumption. The main current building energy-saving materialsare external wall thermal insulation materials which have many disadvantages andcan not be used widely. Based this situation, this paper prepared a new type ofincombustible composite thermal insulation foamed material with low thermalconductivity using inorganic materials with incombustibility and organic polymermaterial with low thermal conductivity and high toughness.Firstly, inorganic foamed board is prepared with inorganic materials as afoamed skeleton of composite thermal insulation foamed material; organic polymermaterial is added as a toughening material to prepare a composite thermal insulationfoamed material; finally, fiber and flexible resin additives are added in order toimprove the physical and mechanical properties of composites.We found that raw materials of inorganic foamed material, phosphoric acid,aluminum hydroxide, magnesium oxide, zinc oxide and calcium carbonate couldreact, foam and be molded at room temperature. The optimal preparation ratio ofinorganic foaming materials are determined by orthogonal experiment: M/P (theradio of the total number of metal atoms and total phosphorus atom of phosphate)value is from1.1to1.3, E (the radio of total number of valence of the metal and thetotal number of valence of phosphates of electrons) is from0.80to0.90, the mo larratio of magnesium oxide and zinc oxide is from0.5to0.7; viscosity of metalphosphate solution is from10mPa·s to20mPa·s; curing process is80℃for4h.The compressive strength of the foamed board is21kPa, brittle rate is21.7%, andthermal conductivity is0.062~0.065W/m·K. The test result reveal that theproperties of inorganic foamed material were poor and need to be improved.Urea-formaldehyde resin was selected as toughening materials of the inorganicfoamed board. Resin content should be controlled at between10%and20%throughanalyzing the influence factors on the quality of the composite foamed board in this study. Composite thermal insulation foamed material with resin content of20%could meet the non-flammability requirements; the compression strength is54kPa,the brittle rate is about8%and thermal conductivity is0.038~0.044W/m·K.Compared to inorganic foam board, the performance of composite foamed boardhave been improved significantly.The study used polyvinyl alcohol (PVA) to modify urea-formaldehyde resin,which is further used to prepared composite foamed board. The test result ofcomposite foam panels (20%resin and6%PVA content in resin) show that thecompression strength is180kPa, the brittle rate is2%and the thermal conductivityis0.039W/m·K. The mechanical performance have been greatly improved.Basalt fiber is chosen to reinforce composite thermal insulation foamedmaterials which is found greatly improved mechanical strength. Thefiber-reinforced composite foamed board is prepared (20%resin,6%PVA content inresin;6%basalt fiber) with thermal conductivity0.038W/m·K, the compressionstrength570kPa and bulk density246kg/m3, and its architectural incombustibletest results meet the incombustible class A standard.