Theoretical and experimental study on sound absorption performance of Al₂O₃-polyurethane foam and microperforated plate composite structure

Abstract

Low-frequency noise pollution in substations has a significant impact on the physical and mental health of workers. Reduction low-frequency noise pollution is an urgent problem to solve for researchers. In this paper, the different structures of Al2O3-polyurethane composites and micro-perforated plate were constructed, and the effects of cavity depth, perforated plate, and foam position on sound absorption properties were comprehensively investigated. The results showed that the position of perforated plate and the arrangement of resonance structure were the two most important factors affecting sound absorption performance. When the sound wave passed through the plexiglass plate–cavity–composites foam–perforated plate in turn, the peak position of sound absorption coefficient was located in the ultra-low frequency range. Meantime, the simulation study showed that the friction between the air column and the cavity wall in the perforated plate can consume sound energy to achieve sound absorption.

Metal and Metal Oxide Nanoparticle Incorporation in Polyurethane Foams: A Solution for Future Antimicrobial Materials?

“…Incorporating antimicrobial agents into polyurethane foams provides them with the ability to combat microbial growth, a feature highly coveted in the medical and hygiene industries [26][27][28]. Furthermore, the infusion of metal nanoparticles and inorganic oxides (including nano forms) bestows advanced functionalities, e.g., enhanced thermal conductivities, superior electrical properties, improved mechanical strengths, reductions in noise pollution, and broad-spectrum antimicrobial activities [20][21][22][29][30][31].…”

“…In addition to their versatility, PU foams are well known for their lightweight nat Their exceptional thermal insulating properties are highly regarded in the construc and refrigeration industries, where energy efficiency is a key concern [32]. The foa ability to dampen sound and reduce noise further broadens their appeal, with app tions in automotive interiors and architectural acoustics [29,30,33].…”