Abstract
An ultralight graphene oxide (GO)/polyvinyl alcohol (PVA) aerogel (GPA) is proposed as a new class of acoustic materials with tuneable and broadband sound absorption and sound transmission losses. The interaction between GO sheets and PVA molecules is exploited in our environmentally friendly manufacturing process to fabricate aerogels with hierarchical and tuneable porosity embedded in a honeycomb scaffold. The aerogels possess an enhanced ability to dissipate sound energy, with an extremely low density of 2.10 kg m−3, one of the lowest values ever reported for acoustic materials. We have first experimentally evaluated and optimised the effects of composition and thickness on the acoustic properties, namely sound absorption and sound transmission losses. Subsequently, we have employed a semi-analytical approach to evaluate the effect of different processing times on acoustic properties and assessed the relationships between the acoustic and non-acoustic properties of the materials. Over the 400–2500 Hz range, the reported average sound absorption coefficients are as high as 0.79, while the average sound transmission losses can reach 15.8 dB. We envisage that our subwavelength thin and light aerogel-based materials will possess other functional properties such as fire resistance and EMI shielding, and will prove to be novel acoustic materials for advanced engineering applications.
Highlights
An ultralight graphene oxide (GO)/polyvinyl alcohol (PVA) aerogel (GPA) is proposed as a new class of acoustic materials with tuneable and broadband sound absorption and sound transmission losses
These are manufactured by ultra-high shear mixing blends of GO and polyvinyl alcohol (PVA) which are embedded in a honeycomb (HC) core, freeze-cast, and freeze-dried
This is a result of the low interfacial tension of PVA, whereas foam stability is improved by changes to surface elasticity and viscosity due to the presence of G O30–32
Summary
An ultralight graphene oxide (GO)/polyvinyl alcohol (PVA) aerogel (GPA) is proposed as a new class of acoustic materials with tuneable and broadband sound absorption and sound transmission losses. We present a new class of ultralight and subwavelength thin acoustic aerogels with high, broadband, and tuneable sound absorption and sound transmission loss These are manufactured by ultra-high shear mixing blends of GO and polyvinyl alcohol (PVA) which are embedded in a honeycomb (HC) core, freeze-cast, and freeze-dried. While alterations of blend composition produce aerogels with different physicochemical characteristics, variations in the time of ultra-high shear mixing changes the structural characteristics Both directly affect the efficiency of sound dissipation through the material and, shape the JCA model as a powerful tool for the understanding of the acoustic behaviour of GPAs. Digital Microscopy (DM), Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FT-IR) and X-Ray Diffractometry (XRD) are used to characterise the physical and chemical properties of the aerogels. The ultralight aerogels manufactured in this work possess high broadband sound absorption, with the optimised GPA potentially being the lightest porous absorber on record at this time
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