Preparation And Performance Analysis Of New Polyurethane Porous Composite Materials In Vehicles

In recent years,with the development of living standards and the automobile industry,consumers have higher requirements for the comfort of car driving.Automotive NVH(Noise,Vibration,Harshness)characteristics,as an important measure of comfort,often attract much attention.Among the NVH characteristics,noise often has the most direct impact on consumers.Acoustic packaging of automobiles is one of the most important means to suppress automotive noise,and polyurethane foam has been widely studied as an important acoustic packaging material.Therefore,it is important to study the preparation and property analysis of polyurethane porous composites.In order to improve the environmental protection and sound absorption performance of petroleum polyurethane foam,various polyols were used to prepare polyurethane foams with different closed pore ratio.Based on the microstructure of polyurethane foam,a periodic cell model with ideal conditions was developed.The theoretical sound absorption coefficients of different foam models were obtained by JCA(Johnson-Champoux-Allard)acoustic model.The experimental results show that the increase of the closed cell rate can improve the sound insulation performance of polyurethane foam.The experimental and simulation results show that the increase of the closed cell ratio can improve the sound absorption effect of polyurethane foam for low frequency noise.The simulation results show that the sound absorption coefficient of polyurethane foam increases and then decreases with the increase of the closed porosity.The change of the closed pore ratio has a greater effect on the flow resistivity and tortuosity factor.To further improve the acoustic and mechanical properties of plant-based polyurethane foams,common polyurethane foams were prepared by using rosin polyol and castor oil instead of some petroleum polyols.The high-performance polyurethane foams were prepared by adding carbon nanotubes(CNTs)and graphene oxide(GO)solution.The acoustic and mechanical properties of the polyurethane foams were analyzed using scanning electron microscope,impedance tube,and pressure tester.The measurement results showed that the addition of CNTs changed the size and shape of the cells and reduced the weight of the polyurethane foam,and the impregnation of GO solution increased its internal complexity and improved the acoustic and mechanical properties of the polyurethane foam.In this paper,multilayer composites were prepared to better fit the use of polyurethane foams in vehicles.Three hybrid plant-based polyurethane foams were prepared using a variety of plant-based polyols,which were mixed to laminate the multilayer polyurethane foam by stitching.The thickness of each layer of polyurethane foam was optimized by using the orthogonal test method,and the effect of the thickness of the foam on the acoustic properties of the multilayer composites was analyzed to finally obtain the multilayer composites with the best acoustic performance.