废弃羊毛吸声复合材料的制备及其性能

Preparation and properties of sound absorption composites based on waste wool

为解决废弃羊毛再生循环利用问题,开发吸声系数高且吸声频带宽的吸声材料,以废弃羊毛为增强材料,乙烯-醋酸乙烯共聚物(EVA)为基体材料,通过热压法制备了废弃羊毛/EVA吸声复合材料。选用传递函数法分析废弃羊毛/EVA吸声复合材料的热压温度、材料密度、废弃羊毛质量分数、材料厚度、后空气层厚度以及废弃羊毛的排列方式等对吸声系数的影响。结果表明:用最优工艺制备的废弃羊毛/EVA吸声复合材料在低中高频都有优异吸声性能;该材料的吸声性能在中低频区域表现突出,在1 000 Hz处吸声系数达到0.9,材料降噪系数达0.65,平均吸声系数为0.6,即该材料为高效吸声材料;为吸声机制声波入射材料内部激发振动,声能转化为动能及热能,使废弃羊毛/EVA吸声复合材料具有优异吸声性能。

In order to solve the problem of regenerative recycling of waste wool and develop sound absorbing materials with high sound absorption coefficient and wide sound absorption frequency band,the waste wool/ethylene vinyl acetate copolymer(EVA)sound absorption composites were prepared by hot pressing method.Waste wool were used as reinforced material and EVA was taken as matrix material.The influence of hot-pressing temperature,density of composites,mass fraction of waste wool,thickness of composites,thickness of the air layer and waste wool arrangement on the sound absorption coefficient were measured by the transfer function method.The results show that the waste wool/EVA sound absorption composites have excellent sound absorption performance at low,medium and high frequencies.The sound absorption performance of the composites is prominent in the middle and low frequency region.The sound absorption coefficient reaches 0.9 at 1 000 Hz,the noise reduction coefficient is 0.65,and the average sound absorption coefficient is 0.6.The sound absorption mechanism of the waste wool/EVA sound absorption composites with excellent sound absorbing properties is that the acoustic energy is converted into kinetic energy and thermal energy by exciting the vibration by sound waves entering the interior of the material.