【作者】 曹书豪；

【导师】 段可；

【作者基本信息】 西南交通大学 ， 机械设计及理论， 2013， 硕士

【摘要】 随着社会工业、交通运输、城市建筑的不断发展,噪声污染已和大气污染、水污染、固体废物污染并列为四大污染。目前控制噪声的最基本手段是利用吸声降噪材料。聚氨酯泡沫(polyurethane foam, PU)是典型的多孔型声学材料,它综合了高分子的材料性能、柔性材料的阻尼功能、多孔材料的吸声功能,是一种很好的吸声材料。因此对PU泡沫材料在声学方面的研究就显得尤为重要。本文首先研究了在PU泡沫材料合成过程中,表面活性剂、催化剂的含量变化对泡孔的孔径、分布均匀度的影响,并进一步研究了其对PU泡沫声学方面的影响。研究表明,表面活性剂、催化剂含量的变化能够影响材料的孔径、分布均匀度及吸声性能。在本文的发泡体系中,当硅油的含量为2wt%、二月桂酸二丁基锡的含量0.4wt%、三乙烯二胺的含量为0.3wt%时,制备的PU泡沫平均吸声系数为0.54,具有较好的吸声效果且泡孔分布均匀。同时研究了PU厚度、空腔厚度、原料温度对PU泡沫的孔结构及吸声性能的影响。结果表明,PU泡沫的吸声性能随厚度、空腔厚度的增加而增强,但厚度的增加存在定的限度。原料温度对泡沫的影响较大。当原料温度为45℃时,泡沫中出现很多的半、闭孔,但吸声性能最好。PU泡沫虽然具有很好的高频吸声性能,但其低频吸声性能较差,因此本文研究了PU泡沫中低频的拓展。首先研究了聚丙烯纤维(polypropylene fiber, PP)的吸声性能。文中考察了PP纤维的长度、样品的密度及厚度对材料的吸声性能的影响。通过研究发现,PP纤维的长度对自身的吸声性能几乎没有影响,但随着纤维样品密度、厚度的增加,样品的吸声性能也随着增加,且中低频吸声性能很好。将PP纤维与PU泡沫叠加放置成双层结构,可以拓展材料的中低频吸声范围且吸声峰值较高。放置的方式对材料的吸声性能有较大影响,面对声源的层状材料起主导作用。研究了PP纤维作为填料加入PU发泡体系共同发泡。结果显示,PP纤维的加入会影响泡沫的泡孔结果,并影响PP-PU复合材料的吸声效果。当PP纤维添加量为0.5g时,材料的吸声性能最好。更多还原

【Abstract】 With the development of industries, transportation and construction, noise pollution has been one of the four pollutions. The most basic means of controlling noise is the sound absorption material. Polyurethane foam (polyurethane foam, PU) is a typical porous acoustic material, which combines the material properties of the polymer and the damping function of a flexible material, is a good sound-absorbing material. So it is significant to study sound absorption property of PU foam material.In this article, we studied the effects of surface agent and catalyst on pore diameter and distribution in the PU foam’s synthesis, and especially on sound absorption properties of PU foam. The results demonstrate that the contents of surface agent and catalyst have great influence on pore diameter, distribution and sound absorption property. In the synthesized system of PU foam in this article, when the contents of silicon, DABCO and DBTDL are2wt%,0.3wt%,0.4wt%respectively, the average sound absorption coefficient of PU foam is0.54, which showed a better sound absorption property and pore scatter uniformity.We also studied the effects of thickness, cavity thickness, temperature of raw material on pore structure and sound absorption property. We found that with the increase of thickness and cavity thickness, sound absorption property of PU foam is improved, the degree of increase is limited. The results also showed that the temperature of raw material has great influence on it. When the temperature is45℃, there are many closed pores and half open pores appeared, which showed the best sound absorption property.PU foam has good sound absorption property in high frequency, while the medium-low frequency is not so good, so we studied how to enhance the sound absorption property in medium-low frequency. Firstly, we studied the sound absorption property of polypropylene (PP) fiber.We investigated the effects of length, density and thickness of PP fiber on sound absorption property. The results show that the length of PP fiber has no influence on sound absorption property, while with the increase of density and thickness of samples, the sound absorption property is improved, and showed better property in medium-low frequency. We discussed the double structure composite of PP layer and PU layer, and found that this manner can enhance the sound absorption property and got a high absorption coefficient in medium-low frequency. The configuration of the PP-PU double-layer structure has a profound impact on its sound absorption property, and the layer which faced the sound source has the dominant function to sound absorption properties.We synthesized PU foam with PP fiber together. The results showed that both pore structure and sound absorption property were changed when the PP fibers exist. When the content of PP fiber is0.5g, the PP-PU showed the best sound absorption property.更多还原