Adding functional fillers to achieve high sound absorption performance of polymeric foams has been proven to be an effective method, but controlling the distribution of fillers is an urgent problem to solve. In this work, waterborne polyurethane (WPU) was combined with melamine foam (MF) by adopting a cyclic freeze–thawing strategy. WPU was able to reorganize several times during the cyclic freeze–thaw process, which facilitated the construction of film-like WPU at the junction of MF skeletons and contributed to improving acoustic absorption performance. The formation of WPU films not only regulated the tortuosity and airflow resistance but also prolonged the sound wave propagation path inside the MF. As a result, the MF/WPU composite foams demonstrate excellent sound absorption performance, which shows a potential for use as high-performance sound absorption material.

中文翻译：

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利用循环冻融改善三聚氰胺/水性聚氨酯复合泡沫的吸声性能

添加功能性填料以实现聚合物泡沫的高吸声性能已被证明是一种有效的方法，但控制填料的分布是一个亟待解决的问题。在这项工作中，通过采用循环冻融策略将水性聚氨酯（WPU）与三聚氰胺泡沫（MF）结合。 WPU在循环冻融过程中能够多次重组，有利于在MF骨架连接处构建薄膜状WPU，有助于提高吸声性能。 WPU薄膜的形成不仅调节了弯曲度和气流阻力，而且延长了MF内部的声波传播路径。因此，MF/WPU复合泡沫表现出优异的吸声性能，显示出作为高性能吸声材料的潜力。