Enhancing Sound Insulation Abilities of Polyurethane Composites Through Molecular Sieve Incorporation

Polyurethane (PU) has a wide range of applications in the field of noise reduction and vibration damping. In order to break through the bottleneck of sound insulation performance of PU, three different kinds of molecular sieves, 3A, 13X, and ZSM-5, with complex pore channels were incorporated into PU through the semi-prepolymer method. The sound insulation properties of PU/molecular sieve composites were obviously improved, especially in the frequency from 1000 to 2000 Hz. The composites also showed enhanced mechanical properties compared with PU. Tensile strengths of up to 15 MPa and elongation at break of 1256.23% were achieved. A slight expansion of the effective damping temperature range was observed. The sound insulation mechanism of PU/molecular sieve composites included fillers increasing the density of PU, microporous channels dissipating sound waves, dissipating energy, and dispersing stress by good compatibility of inorganic and organic phases. The excellent compatibility came from physical and chemical synergies of soft segments perforated molecular sieves as well as the reaction between active groups of PU and acidic sites of molecular sieves. This study provided comprehensive mechanisms and strategies for the enhancement of sound insulation, and more targeted research and application can be conducted in the future.