Study On The Relationship Between Microstructure And Damping Properties Of Polyurethane And Its Composites

Accompany by the rapid development of modern industry,mechanical equipment is more and more high speed,high efficiency and high precision operation.It is urgent to research and develop more simple and effective methods and measures to solve the problems of vibration and noise.The application of damping material is one of the most effective methods to control the vibration and to reduce the noise pollution.Among lots of viscoelastic damping materials,the polyurethane elastomer has the advantages of strong design,simple molding process,good mechanical,damping and low temperature performance,and is favored by more and more people.It is important to study the influence of the microstate of polyurethane material on the damping and sound absorption.Firstly,this paper designs the polyurethane material from two aspects: adjusting the hard segment content and changing the soft segment structure and using MDI100 LL,PTMEG1000,PTMEG2000 and BDO as raw materials to prepare polyurethane.By Fourier Transform infrared spectroscopy(FT-IR),dynamic mechanical test(DMA),traveling wave tube acoustic test,study the effects of hard segment content and mixed soft segment on the damping capacity and the reflection and absorption of 3-8 kHz frequency acoustic waves at atmospheric pressure.Secondly,to eliminate interference influence factors,this paper in the same formula(MDI100LL,PTMEG1000 and BDO)conditions,prepares polyurethane with different curing temperature and different curing process(one-step polymerization method,pre polymer method).The effects of temperature and curing process on the microstructure of polyurethane elastomers are studied by atomic force microscopy(AFM),(FT-IR)and DMA and then analyze the effects of different phase structures on the damping and acoustic properties of polyurethane elastomer.Finally,in order to further study the effect of interface on the damping and sound absorption performance,two kinds of fillers(montmorillonite and vermiculite powder)are added into the polyurethane matrix,increasing the interfacial area of polyurethane materials.By FT-IR,DMA,SEM and so on,studies the effects of filler content and filler type on the damping and acoustic properties of polyurethane composites.