In this investigation, a variety of polyurethane composites with different syntactic hollow spheres were prepared by casting method, using 316 L stainless steel hollow spheres and 316 L stainless steel–Al₂O₃ double‐layer hollow spheres as reinforcements. The sound insulation and absorption properties of polyurethane composites with different syntactic hollow spheres were tested by impedance tube. The effects of the hollow spheres on the acoustic properties of composites were analyzed and compared with polyurethane resin and polyurethane/solid spheres composites. The experimental results reveal that the sound transmission loss of polyurethane can be improved by the addition of hollow spheres, and the range of sound absorption frequency of polyurethane tends to move to lower frequency. Otherwise, the sound insulation and absorption frequency range of polyurethane can be broadened by the effect of 316 L stainless steel–Al₂O₃ double‐layer hollow spheres. In addition, the compressive strength and stiffness of polyurethane composites have been significantly improved after hollow spheres added. Comparing with polyurethane, the compressive strength and stiffness of PU/316 L–Al₂O₃ HS increased by 47.9% and 115.9%, respectively.

中文翻译：

---

具有句法空心球的聚氨酯复合材料的声学/力学性能

在这项研究中，使用316 L不锈钢空心球和316 L不锈钢–Al ₂ O ₃通过铸造方法制备了具有不同句法空心球的各种聚氨酯复合材料。双层空心球作为增强材料。用阻抗管测试了具有不同句法空心球的聚氨酯复合材料的隔音和吸收性能。分析了空心球对复合材料声学特性的影响，并将其与聚氨酯树脂和聚氨酯/固体球形复合材料进行了比较。实验结果表明，加入空心球可以改善聚氨酯的传声损失，聚氨酯的吸声频率范围趋向于降低。否则，通过316 L不锈钢–Al ₂ O ₃的作用，可以扩大聚氨酯的隔音和吸收频率范围双层空心球。此外，加入空心球后，聚氨酯复合材料的抗压强度和刚度得到了显着提高。与聚氨酯相比，PU / 316 L–Al ₂ O ₃ HS的抗压强度和刚度分别提高了47.9％和115.9％。