Double-Porous PET Waste-Derived Nanofibrous Aerogel for Effective Broadband Acoustic Absorption and Transmission

A flexible nanofibrous aerogel with laser-cut perforations was developed for effective sound absorption and insulation. Polyethylene terephthalate (PET) waste bottles were turned into uniform nanofibers (NFs) via an electrospinning technique that were subsequently processed to create a 3D porous network through a freeze-drying method. Reinforcing the aerogel with glutaraldehyde-cross-linked poly(vinyl alcohol) (PVA) allowed mechanical flexibility resulting in a Young's modulus of 2.28 × 10–2 MPa. The highly tortuous pore structure produced by the densely packed nanosized fibers permitted a noise reduction coefficient (NRC) of 0.37 (at areal density of 465 g m–2). Likewise, the overall transmission loss is increased as nanofibers are used instead of microfibers. In terms of sound insulation performance, a standard transmission class (STC) of 6.1 dB, which is about 10 times that of a commercial polyurethane-based acoustic foam, is displayed by the PETNF aerogel. Moreover, the creation of perforations further enhanced the material's sound absorption such that an NRC of 0.54 (at areal density of 930 g m–2) was obtained, which is similar to or greater than that of most fiber-based acoustic materials previously reported. By changing the perforation diameter, one can tune its overall acoustic performance. In addition, utilizing a waste-derived material for noise pollution control alleviates the generation of plastic waste that is detrimental to the environment.