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报道了由聚丁二烯多元醇、MDI和2-乙基-1,3-己二醇为扩链剂制作的浇注型聚氨酯弹性体的机械性能和声学性能。这种弹性体可用于包覆声呐换能器,这种应用对声学性能的基本要求是声速和密度均与水接近来获得与水的声学阻抗相匹配。良好的匹配可以使声信号从水向材料完美通过,但由于高分子本身的黏弹性,总会有些残余不匹配。扩链剂用量的增加可以提高强度、增加硬度、形成微相分离结构。强度较高的材料由于增加了剪切模量和阻尼性导致声学性能变差。样品厚度和声波频率在特定应用范围内时,可以在声学性能和强度之间取一个平衡来满足要求。
The mechanical and acoustic properties of cast polyurethane elastomers made from polybutadiene polyols, MDI and 2-ethyl-1,3-hexanediol as chain extenders have been reported. This elastomer can be used to cover sonotrode transducers. The basic requirements of this application for acoustic performance are that both the speed of sound and the density approach water to match the acoustic impedance of water. A good match will make the acoustic signal pass perfectly from the water to the material, but there will always be some residual mismatch due to the polymer’s own viscoelasticity. Increasing the amount of chain extender can increase the strength, increase the hardness, the formation of micro-phase separation structure. Higher strength materials result in poor acoustic performance due to increased shear modulus and damping. When sample thickness and sound frequency are within specific application ranges, a balance of acoustic performance and strength can be achieved to meet the requirements.