Hong Jin, Cha Sung Woon
School of Mechanical Engineering, Yonsei University, 50, Yonsei-ro, Seodaemoon-gu, Seoul 03722, Korea.
Materials (Basel). 2022 Mar 8;15(6):2007. doi: 10.3390/ma15062007.
Noise pollution critically degrades the quality of human life, and its effects are becoming more severe due to rapid population growth and the development of industry and transportation. Acoustic wave aggregation in the 30-8000 Hz band can have a negative impact on human health, especially following continuous exposure to low-frequency noise. This study investigates the acoustic performance of microcellular foams made of a mixture of brittle and soft materials and their potential use as absorption materials. It is common to use porous materials to improve acoustic properties. Specimens prepared by mixing ceramic and urethane were made into microcellular foamed ceramic urethane by a batch process using carbon dioxide. The specimens were expected to exhibit characteristics of porous sound-absorbing materials. After measuring the acoustic characteristics using an impedance tube, a significant sound-absorption coefficient at a specific frequency was noted, a characteristic of a resonance-type sound-absorbing material. However, the sound-absorption properties were generally worse than those before foaming. Differences based on the size, shape, and structure of the pores were also noted. It will be necessary to check the effects of cellular morphological differences on the absorption properties by controlling the variables of the microcellular foaming process in a future study.
噪声污染严重降低了人类生活质量，并且由于人口的快速增长以及工业和交通的发展，其影响正变得愈发严重。30至8000赫兹频段内的声波聚集会对人体健康产生负面影响，尤其是在持续暴露于低频噪声之后。本研究调查了由脆性和软质材料混合物制成的微孔泡沫材料的声学性能及其作为吸声材料的潜在用途。使用多孔材料来改善声学性能是很常见的做法。通过将陶瓷和聚氨酯混合制备的试样，利用二氧化碳通过间歇工艺制成微孔泡沫陶瓷聚氨酯。这些试样有望展现出多孔吸声材料的特性。在用阻抗管测量声学特性之后，在特定频率下观察到了显著的吸声系数，这是共振型吸声材料的一个特征。然而，吸声性能总体上比发泡前要差。还注意到了基于孔隙大小、形状和结构的差异。在未来的研究中，有必要通过控制微孔发泡过程的变量来研究泡孔形态差异对吸声性能的影响。
