Abstract

With more and more attention paid to the quality of life, noise pollution has been ranked the third in environmental pollution. In this study a symmetrical multi-layer sheet was designed for a sound absorbent material. Needleless electro-spinning nano-membranes of polyurethane (PU) were used as the surfaces of the sound absorbent multi-layer sheets. The effects of the PU concentration, solvent ratio, membrane thickness and solvent additives on the surface morphology of the nano-membranes and the sound absorption coefficient of the sound absorbent sheets were carefully investigated by scanning electron microscopy and sound absorption measurements. The results showed that the optimal spinning solution was 10 wt.% PU and the solvents ratio of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) at 1:1. Under this condition, the average sound absorption coefficient of the multi-layer sheets increased from 0.29 for the 0 mm nano-membranes to 0.57 for the 1.2 mm nano-membranes (spinning time 240 minutes). For the nano-membranes in the range of 0.2–1.2 mm, it was noted that the average sound absorption factor of the multi-layer sheets increased with the increasing of the nano-membranes’ thickness and the absorption frequency for which the highest sound absorption coefficient occurred moved to lower frequencies with the increasing of the membranes’ thickness. By adding sodium dodecyl sulfonate (0.5 wt.%) and sodium chloride (1.0 wt.%) into the optimal solution, a nano-membrane with a nano-cobweb structure of 100% coverage rate was formed. Under the spinning condition of 10 wt.% PU, 1.0 wt.% NaCl, 0.5 wt.% SDS, 1:1 DMF/THF and 240 minutes, a nano-cobweb multi-layer material with an average sound absorption factor of 0.63 was obtained. Although not a large increase from the sound absorption coefficient for the nano-membrane multi-layer sheet material of 0.57, the results showed that the multi-layer sheet with nano-cobweb layer had a great improvement of sound absorption in the range of 500–2000 Hz relative to the nano-membranes. Therefore, a good sound absorption sheet with multi-layer structures was obtained successfully.

摘要

随着人们对生活质量的日益重视，噪声污染已成为环境污染的第三位。在这项研究中，为吸音材料设计了一种对称的多层板。聚氨酯（PU）的无针静电纺丝纳米膜用作吸声多层片材的表面。通过扫描电子显微镜和吸声测量仔细研究了PU浓度、溶剂比例、膜厚度和溶剂添加剂对纳米膜表面形貌和吸声片吸声系数的影响。结果表明，最佳纺丝液为10 wt.% PU，溶剂比为N , N-二甲基甲酰胺 (DMF) 和四氢呋喃 (THF)，比例为 1:1。在此条件下，多层片材的平均吸声系数从 0 mm 纳米膜的 0.29 增加到 1.2 mm 纳米膜的 0.57（纺丝时间 240 分钟）。对于0.2-1.2 mm范围内的纳米膜，注意到随着纳米膜厚度和吸声频率的增加，多层片材的平均吸声系数增加随着膜厚度的增加，系数发生移动到较低的频率。通过在最佳溶液中加入十二烷基磺酸钠(0.5 wt.%)和氯化钠(1.0 wt.%)，形成覆盖率为100%的具有纳米蛛网结构的纳米膜。在 10 wt.% PU 纺丝条件下，1.0 wt. %NaCl、0.5wt.%SDS、1:1 DMF/THF和240分钟，得到平均吸声系数为0.63的纳米蛛网多层材料。虽然与纳米膜多层片材的吸声系数0.57相比增幅不大，但结果表明，纳米蛛网层的多层片材在500-500- 2000 Hz 相对于纳米膜。因此，成功地获得了具有多层结构的良好吸声片材。结果表明，与纳米膜相比，具有纳米蛛网层的多层片材在 500-2000 Hz 范围内的吸声性能有很大提高。因此，成功地获得了具有多层结构的良好吸声片材。结果表明，与纳米膜相比，具有纳米蛛网层的多层片材在 500-2000 Hz 范围内的吸声性能有很大提高。因此，成功地获得了具有多层结构的良好吸声片材。