Research On Preparation Method And Performance Optimization Of Automobile Polyurethane Porous Material Based On Multi-Plant Polyol

The NVH performance affecting vehicle comfort refers to Noise,Vibration and Harshness respectively.As vehicle vibration produces noise and affects comfort,the three are simultaneously and inseparable.In the process of vehicle noise control,acoustic packaging is an efficient and easy to realize way.As one kind of acoustic packaging materials,polyurethane porous materials are widely used in automobiles.In order to echo the call for energy saving and environmental protection,this paper aims to prepare polyurethane porous materials that can meet the sound absorption and mechanical properties,but are also greener and more environmentally friendly.Polyols used in the preparation of traditional polyurethane porous materials are mostly polyether polyols,which belong to a kind of fossil energy and account for a large proportion of raw materials.In view of this phenomenon,in this paper,three plant oil-based polyols are used to replace some polyether polyols to synthesize the green and environmentally friendly porous plant oil-based polyurethane materials.Based on the preliminary experiments,it was found that the foaming effect was good when using corn oil-based polyol instead of polyether polyol to prepare polyurethane porous materials,so corn oil-based polyurethane porous materials were prepared,but the foaming success rate was greatly reduced as the percentage of corn oil-based polyol increased.After that,reducing the content of corn oil-based polyol,and adding soybean oil-based polyol and castor oil-based polyol,the mixture of various plant oil-based polyols was used to increase the percentage of plant oil-based polyol by utilizing the properties of different polyols.In order to ensure the successful preparation,after many experiments,the content of three polyols was limited to 35～45g corn oil-based polyol,5～15g soybean oil-based polyol and 0～5g castor oil-based polyol.A response surface experiment table was designed using response surface method,and the corresponding porous polyurethane materials were prepared according to the contents of three polyols in the experiment table,and the sound absorption and mechanical properties of the samples were tested.In order to optimize the performance of the designed multi-plant polyol polyurethane material,according to the response surface results,three optimal samples are obtained by using genetic algorithm.Among them,the sample with better sound absorption and mechanical properties was the optimized sample 3,whose average sound absorption coefficient was 0.4941,Young’s modulus was 205.305 kPa,and the proportion of plant oil-based polyol replacing polyetherpolyol could reach 54.164%.The microstructure of polyurethane porous materials is fundamental to their properties.Considering that polyurethane porous materials need both better acoustic and mechanical properties in many cases for automotive applications,the microstructure models were established according to the structural parameters of the optimized sample 3.The ordinary periodic tetradecahedral cell cluster model can approximate the microstructure of polyurethane porous materials,but there is a certain gap with the actual structure.Therefore,this paper proposes a model structure of 27-cell cluster to simulate the actual structure as a periodic cell cluster.The 27-cell cluster model contains three tetradecahedral cell with different cell body sizes,and each cell has the same pore size,which is the average pore diameter collected from optimized sample 3.Statistical energy analysis method is an efficient and accurate simulation method for acoustic packaging applications.In automobiles,the roof and front floor acoustic packaging arrangement has a large area and makes a great contribution to the overall vehicle noise reduction,so statistical energy analysis models of the roof and front floor were established using VA one software.In the modeling,the performance parameters of the optimized sample 3 and 27-cell cluster model were added to the acoustic packaging,respectively.Then,the performance parameters of the optimized sample 3 and 27-cell cluster were added to the acoustic packaging model respectively.By simulating and analyzing the sound pressure levels of the roof and front floor receiver cavities of different acoustic packages and the overall sound insulation of the models,the noise reduction performance of the optimized sample 3 was investigated.In addition,the accuracy of the 27-cell cluster model was further verified by comparing the noise reduction effect of the optimized sample 3 with that of the 27-cell cluster model.