Peng Longgui, Lei Lei, Liu Yongqiang, Du Lifei
College of Materials Science and Engineering, Xi'an University of Science and Technology, Xi'an 710054, China.
Materials (Basel). 2021 Jan 3;14(1):195. doi: 10.3390/ma14010195.
Porous materials hold great potential in the field of sound absorption, but the most abundantly used materials, such as Polyurethane (PU) foam and polyvinyl chloride (PVC) foam, would inevitably bring environmental harms during fabrication. In this study, the nontoxic addition-molded room temperature vulcanized silicone rubber is chosen as the matrix, and NaCl particles are chosen as the pore forming agent to prepare open cell foams via the dissolve-separating foaming method. The effect of different amounts of NaCl (0-100 phr) on the cell structure, mechanical and sound absorption properties is investigated and analyzed. The results indicate that the cell structure could be tailored via changing the addition amount of NaCl, and open cell silicon rubber foams could be achieved with more than 20 phr NaCl addition. Open cell silicon foams show the most effective sound absorption for sound waves in middle frequency (1000-2000 Hz), which should be attributed to the improved impedance matching caused by the open cell structures. Additionally, the mechanical properties, including hardness, tensile strength and corresponding elastic properties, gradually decay to a steady value with the increasing addition amount of NaCl. Therefore, open cell silicone rubber foams are capable of sound absorption in middle frequency.
多孔材料在吸声领域具有巨大潜力，但最常用的材料，如聚氨酯（PU）泡沫和聚氯乙烯（PVC）泡沫，在制造过程中不可避免地会带来环境危害。在本研究中，选择无毒的加成模塑室温硫化硅橡胶作为基体，选择氯化钠颗粒作为成孔剂，通过溶解分离发泡法制备开孔泡沫。研究并分析了不同用量的氯化钠（0-100 phr）对泡孔结构、力学性能和吸声性能的影响。结果表明，通过改变氯化钠的添加量可以调整泡孔结构，添加量超过20 phr时可制备出开孔硅橡胶泡沫。开孔硅泡沫对中频（1000-2000 Hz）声波表现出最有效的吸声效果，这应归因于开孔结构导致的阻抗匹配改善。此外，随着氯化钠添加量的增加，包括硬度、拉伸强度和相应弹性性能在内的力学性能逐渐衰减至稳定值。因此，开孔硅橡胶泡沫能够在中频范围内吸声。
