Improved Sound Absorption Performance of Melamine/Waterborne Polyurethane Composite Foams Using Cyclic Freeze–Thawing

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.