聚合物材料的吸音系数-温度-频率三元关系的研究

用驻波管技术研究了聚甲基丙烯酸乙酯（ＰＥＭＡ）和聚氯乙烯（ＰＶＣ）的吸声系数。结果表明，在玻璃化转变区域材料的吸声系数较高，ＰＥＭＡ和ＰＶＣ均具有特征吸收频率。当乍于玻璃化转变区域时，ＰＥＭＡ和ＰＶＣ的特征吸收峰的数目增加，用自由体积理论对此进行了解释。得到ＰＥＭＡ和ＰＶＣ的吸声系数－温度－频率的三维关系图。

Studies on the Sound Absorption Coefficient-temperature-frequency Relationship on Polymer

The sound absorption coefficients of polyethyl methylacrylate(PEMA) and polyvinyl chloride(PVC) were investigated by means of the impedance tube technique. The results showed that the sound absorption coefficient of the materials exhibited a higher value in its glass transition region due to the more sound energy lost by converting it into the heat energy. Moreover, the further studies discovered that PEMA and PVC possess the characteristic sound absorption frequencies. When the PEMA and PVC were in their glass transition region, the number of their characteristic absorption peaks increased. The phenomena can be partly explained from free volume theory. The diagrams on the three-dimensional relationship of sound absorption coefficient-temperature-frequency for PEMA and PVC were obtained which were of important significance in the application of noise reduction.