Performance Analysis And Application Of Polyurethane Composites Based On Plant Alcohol

Polyurethane is widely used in the field of vehicle acoustic packages because of its advantage in light weight,sound absorption,sound insulation,easy-processing and low cost.With the strengthening of environmental awareness,use of nonrenewable resources gradually attracts the attention of various industries.Polyol based on petroleum,one of the raw materials for preparing traditional polyurethane foam,is one of the nonrenewable resources.Therefore,it's important to seek other renewable raw materials instead of petroleum polyols.Polyurethane has poor sound absorption performance in low frequency range and it can be improved by optimizing its formulation or changing structural parameters.It's necessary for automotive to have better sound and noise reduction performance.This paper selects linseed oil polyol to replace some petroleum polyols to prepare polyurethane materials.The influence of the amount and combination of different raw materials(linseed oil polyol,polyether polyol 3630,epoxy resin E44)on the synthesized polyurethane foams was studied by the control variable method.The performance of the synthesized samples was evaluated by compression mechanical properties test,infrared spectroscopy test and sound absorption performance test.In this paper,the raw material of linseed oil polyol and polyether polyol 3630 ratio of 2:3 was selected.The effects of isocyanate,deionized water and amine catalyst A33 on the sound absorption properties of linseed polyurethane were studied.The response surface-center composite test design method is adopted using the mean sound absorption coefficient as the evaluation index.Finally,the best formulation for linseed polyurethane foam was decided(the content of isocyanate is 34.34 g,deionized water is 2.15 g,amine catalyst A33 is 1.03 g).The polyurethane foam was prepared according to the obtained optimal formulation,and the sound absorption coefficient curve,porosity,density,air-flow resistance,cell structure and mechanical properties of the polyurethane foam prepared by the conventional petroleum-based polyether polyol were compared.The influence of the number of density gradient layers and the selection of the incident end of the sound wave on the acoustic properties of the material was studied.For polyurethane foams with different density gradients,the sound absorption performance is significantly improved compared to the original samples.The choice of the incident end of the sound wave has a greater influence on the sound absorption coefficient curve of samples than the number of layers.The number of layers has a greater influence on the sample sound insulation curve than the choice of the incident end of the sound wave.The sound properties of polyurethane composites were studied when the filler content is 1,2,3 g or whether it is treated with NaOH solution.For the corncob filler,the prepared polyurethane foam has poor sound absorption performance after the NaOH solution treatment.Adding corncob filler without NaOH solution can improve the acoustic properties of materials in some frequency regions.In the interval of adding 1-3 g of filler,the obtained polyurethane sample has the best sound absorption performance when the corncob filler is added to 2 g.Based on the statistical energy analysis method,linseed polyurethane is applied to the acoustic package structure of the front panel and floor of the automobile.The changes of sound pressure level and the change of sound insulation curve of the receiving cavity before and after the change of the acoustic package material were studied.Applying linseed polyurethane to the acoustic package structure of the dash panel and floor in the simulated frequency range,acoustic absorption sound coefficient curve and sound insulation curve are improved.The total sound pressure level of the receiving cavity is reduced by 0.16 dB and 2.91 dB,respectively.