Preparation And Properties Of Heat-resistant And Water-resistant Inorganic Sound-absorbing Materials

Inorganic sound-absorbing materials have many advantages,such as good heat resistance,good flame retardancy,high strength and stable performance,The porous sound-absorbing materials of inorganic sound-absorption materials is slightly smaller and more applied.The hole making process of inorganic porous sound-absorbing material is more difficult,it uses cement as a bonding material.Reducing the density of the sound absorbing material,improving the sound absorption performance and strength are still the direction of the research.The research on the bonding material of porous sound-absorption materials using phosphate adhesives is less,the research of making sound-absorbing materials with hollow microspheres is not many.The experimental use of fly ash hollow microspheres as the main raw material can increase the apparent porosity of the material and simplify the production process.In this paper,fly ash hollow microspheres and inorganic phosphate adhesives are used as main raw materials,and then further solidified after molding,so as to prepare porous inorganic sound-absorbing materials.In order to determine the curing temperature,DSC,TG and DTG were used to study the temperature transformation of adhesive,and then determine the cure temperature 300 ~oC;The optimum molding pressure of the sound-absorbing material is determined by comparing the sound-absorption coefficient and the surface morphology by different molded specimens,then determine the optimum molding pressure is 3 MPa.The experiments were conducted according to the mass ratio of hollow microspheres and phosphate adhesives,such as 1.0:1.0,1.0:0.75 and 1.0:0.6,and the ratio of phosphate with curing agent is 1.0:1.0,1.0:0.80 and 1.0:0.6,a variety of sound absorbing materials were prepared.We screened and optimized the comprehensive performance of porous sound-absorbing materials,determined the best experimental process by comparing their comprehensive properties,then further explored the performance of the sound-absorbing material.The maximum sound absorption coefficient of the selected sound-absorbing material is0.7,the average sound absorption coefficient is above 0.5,the sound absorption frequency is larger,which indicates that its sound absorption property is excellent and belongs to the ideal sound-absorbing material.The physical properties of sound-absorbing materials were tested.Their compressive strength,apparent porosity,water absorption,bulk density and thermal conductivity is 3.8 MPa,57.8%,96.6%,0.57 g/cm3,0.291W/(m.K),it shows that it is not easy to break,more pores,small density and less thermal conductivity.Treatment of sound absorbing materials in high temperature and high humidity environment,it show that the sound-absorption coefficient,compressive strength and micromorphology are stable,and it is known that the micromorphology is complete through SEM,and it is not affected by high temperature and high humidity environment.The sound-absorbing material are processed in-60 ~oC to 1000 ~oC environment then testing its performance,the sound-absorption coefficient,compressive strength and microstructure are stable,it show that the material has good temperature adaptability,it don,t change because of the high temperature and low temperature.The sound-absorption performance is tested after changing the thickness of the sound absorbing material;the sound-absorption performance increases with the increase of the material thickness.The sound-absorption performance is tested by semi perforation on the surface of the sound-absorbing material;it is known that a small amount of perforation is beneficial to the improvement of sound-absorption performance.The sound-absorption performance of one side of the sound-absorbing material is completely closed,it is found that it basically loses its sound-absorption performance,which indicates that adding the surface coating on the side of the sound-absorbing material is not conducive to improving its sound-absorption performance.The sound insulation of sound-absorbing materials in 1600Hz is similar,which indicates that its sound insulation performance is relatively stable,and its sound insulation performance is relatively stable.The average sound insulation is 37dB,and the sound transmission rate is only 0.02%,which indicates that it has a certain sound insulation ability.