| Energy is the material foundation of a country's economic development,the rational use of energy has an irreplaceable role in the progress and development of society.At present,the energy consumption of buildings in China accounts for more than 30% of the total energy consumption in society,and building energy conservation has become the core of China's energy development strategy.Rigid polyurethane foam(RPUF)is widely used in building exterior wall insulation due to its excellent thermal insulation properties.However,rigid polyurethane foam is an organic polymer material,it is relatively easy to burn.Once a fire occurs,it will cause huge personal injury and property damage.Therefore,it is necessary to carry out flame retardant modification treatment of rigid polyurethane foam to prepare a kind of new flame retardant polyurethane insulation material.This article first compares the advantages and disadvantages of several commonly used building insulation materials on the market,and discusses how to modify the flame retardant properties of rigid polyurethane foam.Then,ammonium polyphosphate(APP)and magnesium hydroxide(MH)were added to synthesize flame retardants according to different ratios to synthesize polyurethane rigid foams to prepare multiple groups of flameretardant polyurethane rigid foams.The critical oxygen index tester,horizontal and vertical combustion tester,cone calorimeter and electronic universal testing machine were used to study the flame retardancy,combustion behavior and compressive strength of polyurethane foams with different ratios of ammonium polyphosphate and magnesium hydroxide.And the scanning electron microscope was used to observe the microstructure of the charcoal after combustion of the flame retardant material.Finally,through the HY-EP software,the annual load simulation calculation of buildings using polyurethane boards and expandedpolystyrene boards as insulation materials was performed.The main conclusions are as follows:(1)Ammonium polyphosphate can significantly enhance the flame retardancy and mechanical properties of polyurethane,and as the content of ammonium polyphosphate increases,the better the flame retardancy of polyurethane and the compressive strength.When the ammonium polyphosphate is added in an amount of 40 parts,the limiting oxygen index of the composite material reaches 26.2%,and the vertical combustion reaches UL-94V-0 level.APP can improve the fire safety of polyurethane.The maximum heat release rate of PUF/APP 40 composites is 20.3% lower than that of pure polyurethane rigid foams,and the total heat release is reduced by 17.4%.The foam is dense with charcoal and has good flame retardant effect.(2)The addition of magnesium hydroxide enhances the flame retardancy of PUF/APP/MH composites,and effectively reduces the amount of smoke and poisonous gas generated when the composites are burned.The limiting oxygen index of the PUF/APP30/MH10 composite reached 27.5%,the maximum smoke release rate was 60.4%lower than that of pure polyurethane,and the peak of carbon monoxide production was43.1% lower than that of the PUF/APP20 sample.With the addition of magnesium hydroxide,the compressive strength of the composite gradually decreases,cell structure damage is more obvious,and the mechanical properties of the polyurethane are greatly affected.(3)The results of the annual load simulation calculation using HY-EP software show that The total load of the envelope structure of an office building in Taiyuan City using polyurethane board as insulation material is 1482.18kW·h lower than that of expanded polystyrene board as insulation material throughout the year,which has better thermal insulation and energy saving effects. |
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