Studies On The Preparation And Properties Of Damping And Acoustic Absorption Composites Based On Chlorinated Polyethylene

With the development of the industrial society,more and more noises have appeared in equipment manufacturing,transportation and other industries.Noise has become a serious pollution problem affecting people’s production and life quality after air pollution,water pollution and soil pollution.Noise is caused by vibration,which will not only produce a lot of noise and bring adverse effects to people’s health,but also shorten the life of equipment and reduce the mechanical accuracy,which is one of the important reasons to hinder the progress of technology.Therefore,controlling vibration and reducing noise are important problems should be solved urgently.Polymer materials have good viscoelasticity and are commonly used as damping materials.In this paper,organic small molecules 4,4?-Methylenebis(2,6-di-t-butylphenol)(AO-4426)were added to the chlorinated polyethylene matrix(containing about 40% chlorine by weight)to prepare the CPE/AO-4426 composite material with two damping peaks.The method of preparing hybrid system of organic small molecule and polar polymer to modify polymer damping material was used in the paper.DMA,DSC,SEM and FTIR were used to analyze the microstructure of composite material,hydrogen bonds form,loss modulus,storage modulus and loss factor and explore the damping mechanism of the composite.And tested the mechanical properties of the composites for industrial applications.On these bases,the influence of 2,2’-methylene double-(4-methyl-6-tert-butylphenol)(AO-2246),a small organic molecule with similar structure to AO-4426,on the properties of composites was also investigated.The reason for the significant difference in the properties of composites was obtained by adding two organic small molecules to the same matrix.To expand the use of CPE/AO-4426 damping material,palm fiber,a natural porous fiber,was introduced into the composite material for the first time.The acoustic test showed that the composite material had good sound absorption characteristics and become a kind of damping sound absorption composite material.The main research conclusions of this paper are summarized as follows:(1)In the CPE/AO-4426 composite material,when the content of organic small molecule AO-4426 was low,they had good compatibility with CPE matrix.In this case,there were only a few white organic small molecule crystal particles in the composite material,and the tan δ-T curve had only one damping peak.When the content of organic small molecules increased,a few of AO-4426 were compatible with the CPE matrix as hybrids.The excess organic small molecules existed in the composite as crystal particles,showing phase separation characteristics.A new damping peak appeared in the tan δ-T curve.At the moment,intermolecular hydrogen bonds were formed between the α-H in CPE matrix and-OH in AO-4426,which greatly improved the damping performance of the composite.(2)In the preparation process of composite materials,the pressure condition and temperature condition had a critical value.When the process condition was close to the critical value,composite materials had better damping performance.The change of pressure conditions changed the rate of temperature transfer.When the pressure was too high or too small,on the one hand,it affected the structural stability of intermolecular hydrogen bonds in the composites,resulting in the reduction of hydrogen bonds.On the other hand,the existence of organic small molecular crystal particles in the composite material was reduced,thus reducing the damping capacity of the composite material.According to the research,it was found that temperature conditions and pressure condition were equivalent to some extent.(3)The structure,damping and mechanical properties of CPE/AO-2246 composite were tested and compared with that of CPE/AO-4426 composite in this paper.Because different relaxation processes for the two different composites,the organic small molecules AO-4426 and AO-2246 with similar structures had completely different morphologies and damping properties with the same CPE matrix.(4)CPE/AO-4426 /PF composite was prepared by introducing sound absorption mechanism into CPE/AO-4426 /PF composite.The palm fiber was randomly distributed in the material,maintaining its original hollow structure.The damping performance of composite decreased due to the destruction of matrix continuity,while its sound absorption performance improved with the increase of palm fiber,thus obtaining the composite material with good damping and sound absorption performance.The mechanical properties were tested and the strength was greatly improved,which provided a basis for engineering practice.