Development of a new nanofibrous composite material from recycled nonwovens to improve sound absorption ability

Abstract

Composite structures with various stacking sequences were formed by combining electrospun polyurethane (PU) nanofibers with needle-punched recycled nonwovens from polyester textile wastes and bottles as a new sound absorption material in order to contribute to the solution of noise control and waste generation. PU solutions of 12, 13, 14 and 15 wt % concentrations were prepared for nanofiber optimization studies. Scanning electron microscope (SEM) images showed that the bead free nanofibers were obtained with diameters 296.5 and 509.9 nm from 13 and 15 wt % PU concentrations, respectively. In order to evaluate the potential of nanofibers and nanofiber-recycled nonwoven composites as noise reduction materials; sound absorption coefficients (SACs) were measured and noise reduction coefficients (NRCs) were calculated. The most ideal sample was regarded as the 3.24 mm thick sandwich structure (recycled nonwoven-nanofiber-recycled nonwoven), coded with A250-1320-A250 with a 0.504 NRC value. When the two nanofiber diameters were compared, finer nanofibers (296.5 nm) and finer nanofiber enhanced nonwovens had better NRCs than the thickers (509.9 nm) of the same. The developed composite materials can be regarded as promising sound absorbers.