Sound Absorption And Flame Retardent Properties Of Diatomite / Polyurethane Porous Composite Material

Noise pollution has been a contemporary worldwide issue, and listed as world’s three major pollution together with water and air pollution. Porous materials have been widely used in noise management, diatomite can meet the requirements of the porous sound absorption material with possessing special hole structure, large porosity, low density, heat-resistant and certain strength. Polyurethane foam has been widely used in all kinds of fields such as construction, transportation, life and so on, with possessing merits such as lightweight, high specific strength, shock absorption, sound absorption. However, polyurethane foam burns easily in the air, the limiting oxygen index is only 17.3%, and the combustion reaction generates a lot of smoke and toxic gases, which does great harm to people’s lives and property. To this end, the paper does research on a good flame retardant polyurethane foam composite material, which has good sound absorption and compression performance, and also excellent flame retardant properties at the same time.Diatomite/Polyurethane porous composite material is successfully made by means of free foaming method and molding method with diatomite, polyol, isocyanate, blowing agent, open cell agent and flame retardant agent as raw materials. The paper focuses on the influence of the molding process, coupling agent modified, density and flame retardant agent on the organization and properties of the composite. The results of this study show that:Diatomite/Polyurethane porous composite material made by free foaming method exhibits higher sound absorption characteristic, the sound absorption coefficient is 0.88. The material prepared by molding method exhibits higher compression characteristic, the compressive strength reaches 369 KPa, which is about 1.6 times of the material made by free foaming method.Diatomite/Polyurethane porous composite material modified by Zirconium coupling agent shows the best compression characteristic, the compressive strength and elastic modulus are 225 KPa and 5032 KPa, respectively. In the best content range of 0.5% to 2% of coupling agent, the compressive strength and elastic modulus of the composite material at first increase and then decrease with the content of zirconium coupling agent increased. It shows the best compression characteristic when the content of Zirconium coupling agent is 1%.The compressive strength of Diatomite/Polyurethane porous composite material increases from 115 KPa to 1763 KPa when the density increases from 0.05g/cm3 to 0.20g/cm3. The sound absorption property is decided by porosity and pore size, and the porosity is closely related to the density of the material, the porosity and pore size decrease with the increase of the density, resulting in lower sound absorption property. The internal pressure of the cell and the cell radius exist quantitative relationship, in the same reduction, the smaller the cell radius is, the larger the interal pressure increases, and the easier the cell ruptures.LOI value of the composite made by TCPP/DMMP increases with the increase of DMMP in the complex system, and which is higher than LOI value of single TCPP or DMMP at the same content. When the mass ratio of TCPP/DMMP is 10/30, its maximum LOI value is 30%, close to the B1 level.