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

Abstract

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.

Enhanced Low Frequency Sound Absorption of Bilayer Nanocomposite Acoustic Absorber Laminated with Microperforated Nanofiber Felt

“…A doubleporous aerogel based on PET nanofibers that was previously reported exhibits an NRC of 0.54, which has exceeded most of the reported sound absorbers in terms of their overall absorption performance. 28 However, the reported high rating is a result of a very thick aerogel, which is about 30 mm. In this work, the introduction of the nanofiber felt into the cryogel resulted in an SAA rating of 0.5 (Figure 4a), which is the same degree of absorption enhancement in the thicker aerogel previously reported.…”

“…Its physical properties, such as Young's modulus, porosity, and density, were optimized in our previous work. 28 In this work, the cryogel was utilized as the porous layer for the fabrication of the allnanofiber nanocomposite sound absorber. While porous materials exhibit good sound performance at high frequencies, resonant sound absorption materials, on the other hand, possess good low-frequency sound absorption.…”

“…In this work, the introduction of the nanofiber felt into the cryogel resulted in an SAA rating of 0.5 (Figure 4a), which is the same degree of absorption enhancement in the thicker aerogel previously reported. 28 This is significant especially when constructing building materials for sound control, as it will not take much space when installed in rooms or building architectures. The enhanced absorption of the low frequency as well as the mid frequency dominates the significant increase in the SAA rating (Figure 4b).…”

Structural Investigation on Electrospun Nanofibers from Postconsumer Polyester Textiles and PET Bottles

“…Hossain et al recently investigated the morphological, mechanical, moisture management, and filtration properties of their electrospun NF obtained from PET bottles and demonstrated the suitability of the membranes in air filtration applications . Additional works have included the development of functionalized recycled PET-based membranes for oil/water separation and water treatment as well as acoustic adsorption and sound transmission …”

“…8 Additional works have included the development of functionalized recycled PET-based membranes for oil/water separation 9 and water treatment 10 as well as acoustic adsorption and sound transmission. 11 Regarding the use of postconsumer polyester fabrics as a source for electrospinning, Chen et polyester fabrics for applications in sweat transportation and thermal management. 12 Although several applications of postconsumer PET NF have been reported, systematic investigations on the structural, thermal, and mechanical properties of those NF have been largely overlooked.…”