| The building energy consumption has been one of three "energy- consumers" with industrial energy consumption and transportation energy consumption in our country. There are existing problems with the high energy consumptio n and low energy efficiency in China’s building. Compared with the developed countries with the same climate, per unit area of the building energy consumption in our country is two to three times higher than theirs. Building energy consumption accounts for about a quarter of total energy consumption of the society. It is significant to promote building energy efficiency for the sake of relieving the pressure of energy shortage and sustainable development of energy source. External insulation technology is the critical part of energy conservation in building, and the effective way to realize building energy conservation is to increase the amount of wall insulation material. Considering those performance deficiency and security defects with common external insulation materials, study of new external thermal insulation material with excellent insulation property and incombustibility is extremely imminent.This paper aims to prepare a composite foam insulation material which combines excellent incombustibility with inorganic insulation material and insulation property of organic insulation material, by means of adding organic polymer material to inorganic foamed system as a toughening material.Phosphorus-containing compound has excellent flame retardant, and the aluminum phosphate has a high adhesion. It is found that porous inorganic insulation material could be molded at room temperature by mixing phosphoric acid, aluminum hydroxide, magnesium oxide, zinc oxide and carbonate. The foam materials ratio and process parameters have been optimized by orthogonal experiment: M / P(the radio of the total number of metal atoms and total phosphorus atom of phosphate) value is from 0.7 to 0.9, viscosity of metal phosphate solution is from 12 m Pa·s to 20 m Pa·s, curing temperature is 80℃, curing time is 4h. The thermal conductivity of the inorganic foamed board is 0.0639 W/m·K, complying the national standard of grade-A incombustible material, in wich compressive strength is 27.8 k Pa, and brittle rate is 18.9%. Considering of the poor mechanical properties of the inorganic insulation material, toughening modification would be needed.Water-soluble phenolic resin was chosen as toughened resin to improve the mechanical properties of phosphate foam material. The molar ratio of phenol and formaldehyde is 1:2.5, and it is appropriate that the temperature of the system is controlled at 85 ℃.The compressive strength of obtained water-soluble phenolic resin is 7.8 MPa, and water absorption is 24.6%. Polyvinyl alcohol is selected as the modifying agent to solve the problem of high brittleness and water absorption with the obtained water soluble phenolic resin by chemical modification, and the appropriate polyvinyl alcohol content is 4.5wt%. Compared with the unmodified resin, the water absorption of PVA modified resin reduced to 16.2%, and compressive strength rose to 9.6MPa. A preliminary study of polyvinyl alcohol modification mechanism has been accomplished by FTIR and TG, and it is found that polyvinyl alcohol has no great effect on the thermal performance of PVA modified resin while improving the brittleness and water absorption.The composite foam insulation material is prepared by blending the modified resin and phosphate inorganic insulation material. The effect of adding different modified resin content to composite foamed insulation material is analyzed, and we found that the modified resin content of 25wt%would be appropriate.The compressive strength of the composite foam insulation material is 213.7KPa, thermal conductivity is 0.0314W/m·K, apparent density is 0.467g/cm3, volumetric water absorption is 5.7%, brittle rate is 7.6%, the incombustible experiment shows that composite foam insulation material meets the national standard of grade-A incombustible material. |
