The Fabrication And Properties Of Sound Absorption And Sound Insulation Composites Based On Abandoned Fibers

According to statistics,there are about twenty million tons of discharges related to abandon fibers in China.It not only caused staggering waste,but also polluted the environment and hiddened fire hazard.How to recyle these abandoned fibers to fabricate high value-added products was imminent.Noise pollution became more and more serious.Hence it was very important and aurgent task to develop the excellent sound absorption and sound insulation materials to control noise effectively.Abandoned fibers adopted as reinforced materials,on the other hand polyurethane and polypropylene adopted as matrix materials.This paper used mix molding-hot pressing methods to fabricate sound insulation and flame retardant composites.At last,this paper added polypropylene felt compound to prepare multilayer structure sound absorption-insulation and flame retardant composites.This paper got the conclusions were as follow:First of all,the fabrication and properties of composites based on abandoned fibers.According to the mix orthogonal experiment of L12(42×31)could prepared four kinds of composites.They were abandoned cotton/polyurethane,abandoned cotton/polypropylene,abandoned jute/polyurethane and abandoned jute/polypropylene respectively.Conclusions were as follow.(1)These four kinds of composites had poor sound absorption coefficient.That was to say sound absorption property was not good.On the other hand,transmission loss increased with the increased of frequency and had larger value in the high frequency.That was to say,they had a good sound insulation property.The maximum value was up to 30dB.(2)The limit oxygen indexes of these four composites were less than 20,so they belonged to flammable materials.(3)Transmission loss acted as detection index.It was concluded that the optimal materials were jute fiber and polyurethane.The optimal molding processes were the hot-pressing pressure was 5MPa,the hot-pressing time was 10min,hot-pressing temperature was 175?,proportion was 4:6 and the thickness was 6mm.Second,the fabrication and properties of sound insulation and flame retardant composites based on abandoned fibers.Jute fiber and polyurethane were adopted as raw materials.Before the mix process,jute fibers were soaked in ammonium polyphosphate.And added iron powder as inertial and expansion type flame retardant during the mix process.Conclusions were as follow.(1)Sound absorption property unchanged,while sound insulation property of composite improved obviously.The maximum value was up to 38.52dB.(2)Through the range analysis,we got the conclusion that the mass fraction of iron powder was the most important factors that affected the sound insulation property.(3)The overall limit oxygen index of the composite increased significantly,reached the standard of the flame retardant.Third,the fabrication and properties of sound absorption-insulation and flame retardant composites based on abandoned fibers.Jute/polyurethane composite were combined with the polypropylene fiber mat layer to prepare multi-layer composite sound absorption structure.Conclusions were as follow.(1)With the increased of polypropylene fiber mat layer,the sound absorption coefficient of the multilayer composite sound absorption structure was increased.When the polypropylene fiber mat layer was 4 layers,the absorption coefficient reached 1 at high frequency.(2)The sound absorption property of multi-layer composite sound absorption structure was strongly influenced by combination.(3)When the polypropylene fiber mat layers were the same,if surface impedance and air impedance matched,the sound absorption coefficient was larger.On the contrary,the sound absorption coefficient was smaller.(4)Compared with the single layer material,the sound insulation property of double material had been greatly improved.(5)New nitrogen alkogxy hindered amine flame retardant had excellent flame retardant effect to polypropylene felt,the limit oxygen index reached 28.4.