Preparation And Acoustic Properties Of The Layered Graphene/Poly(Vinyl Chloride)/polyurethane Composites

As the development of modern industry,the problem of noise pollution has increasingly affected people's health and life.Currently,the method for reducing noise is commonly setting soundproofing material as a shelter in the path of sound transmission,but the traditional soundproofing material has many shortcomings,that limits its application in the field of noise control.Because of light weight,high damping,easy processing and so on,polymer materials can play a important role in the control of noise.It is necessary for modification of the polymer materials and structural design to obtain effective noise reduction materials.In this study,graphene was mixed with polyvinyl chloride(PVC)to prepare graphene/PVC(G/PVC)sound insulation material.Diatomite earth(DE)was mixed with polyurethane(PU)to prepare DE/PU foamed composites for sound absorption.The single layer of sound absorbing material was placed in the middle of two layers of sound insulating materials for make them to a layered structure material by hot pressed.The main works are as follows.Graphene was prepared by graphite for raw material.It was found that the graphene layers' distance have a significantly increased and graphene dispersed well in the solvent by characterized.G/PVC composites with different loading of graphene were prepared by solution blending and melt blending.The results showed that graphene could be well dispersed in the composites observed from the fracture by SEM.After the dynamic mechanical properties and sound insulation performance of G/PVC composites were tested,it was found that the higher loading of graphene,the more hindered the movement of PVC molecular chain,then the stiffness,areal density,the storage modulus and the sound insulation were increased much.A significant enhancement in the properties of neat PVC was obtained with a 1 wt% loading of graphene,such as a 150% increase in storage modulus and 12% improvement of sound insulation.A series of DE/PU foamed sound-absorbing materials with different loadings of DE were prepared by melt blending of DE,AC foaming agent and PU pellets by means of compression molding.SEM images indicated that pores in the foamed material were of uniform size and complete structure,which has a great help to the sound absorption properties of the materials.The dynamic mechanical analysis and sound absorption characterization showed that damping of the foamed material was up firstly,down later with the higher loading of DE.The loss factor of neat PU is increased by 0.3 with a 10 wt% loading of DE,the damping and average absorption coefficient were also achieved to the highest.The monolayer DE/PU foamed material was placed in the middle of two layers of G/PVC composites,and then they were combined into sandwich-liked layer structure material by hot pressed.The average sound insulation is about 40 dB with a 1 wt% loading of graphene in G/PVC,which is about 25% higher than pure PVC.It means that the sound insulation of the material obviously increased.The rigid polymer sound insulation material and the foamed polymer sound absorption material were effectively combined through the simple design of sandwich-liked layer structure,which could broaden the application of the acoustic material with different noise reduction mechanisms.The sound waves would reflect or scatter repeatedly in the layered structures to reduce the sound energy in the purpose of noise reduction.