Design Of Polyurethane Porous Material Formulate And Research On Properties Of Sound Absorption

The noise pollution and water pollution, air pollution are becoming to be the three worst problems of environmental pollution in the world. Porous materials have been used widely in noise control engineering. The study of porous polyurethane material to reduce noise is becoming more and more important. This paper is research on the structure of porous materials and the properties of sound absorption.The principle of optimal design of the sound absorption formula of polyurethane porous materials is based on urban road traffic noise features. The scanning electron microscopy is performed to calculate the opening porosity rate of the material and the particle size is demonstrated by analysis software.The mechanical properties, absorption coefficient, noise figure are characterized by using universal testing machine.HCFC-141b, pentane, water are used as foaming agent which can regulate to size distribution of foam pore. Pentane, as blowing agents, is immiscible and can not control the foam structure.The use of HCFC-141b and water as blowing agent can control the foam structure. Catalysts affect the reaction rate of polyurethane porous materials . Ethylene diamine and dilaurate dibutyltin compound at ratio of 1.0:0.6 can control foam distribution, and time match, which will help prepare the opening material. Foam stabilizer can reduce the surface tension of porous material, the amount of silicone foam stabilizer is 1%wt, the stability of foam structure is increased by adjusting the formula of the main factors. we synthesis seven groups of closed-cell samples, the diameter are 320μm, 470μm, 570μm, 660μm, 760μm, 860μm, 1050μm, respectively. Liquid paraffin served as a poor opening holes agent. OR-501 can synthesis samples at a different hole opening rate, the opening rate is 88.6% at a amount of 4%wt OR-501. The absorption coefficient of closed-cell foam were measured using standing wave tube, the results show that with the increase of pore size, the absorption coefficient increased in the 200 ~ 1000 Hz, the optimum value is about 760μm in diameter openings rate is an more important factor in absorption properties of porous materials for the pore size of 760μm porous material. When the opening rate increases to 88.6%, the maximum absorption coefficient at high frequencies can reach as high as 0.98, the maximum absorption coefficient is 0.66 at low-frequency of 250 ~ 600Hz. The absorption coefficient increased by 100% compared with closed-cell material which can obviously improve the shortage of poor absorption in low-frequency sound. The internal transmission path and loss mechanism of noise in the polyurethane porous material were also analysis in the present work.