Facile fabrication of green and sustainable functionalized Bombax ceiba L. wood based aerogel for multifunctional applications

Design and development of biobased porous, strong, and anisotropic aerogels through easy and ecofriendly process for multifunctional applications has been research priority for the globe. Wood is considered as a preferable renewable precursor to prepare aerogels with inherent heirarchical structure and high porosity. In this work, Bombax ceiba L. wood has been delignified through a top to bottom process to develop wood aerogel (WA) which retain the heirarchical nature of wood. Wood aerogel (WA) was functionalized with 3-Aminopropyl triethoxy silane (APTES) to graft silane functionality for achieving multifunctional applications like oil/water separation, thermal insulation, acoustic panel making etc. Prepared delignified and silanised wood aerogels (DWS10 or DWS) showed good surface morphology, impressive super hydrophobicity (167.6 degrees & PLUSMN; 5.4 degrees) and high compression modulus of 82.6 & PLUSMN; 5.0 MPa which is 3.75 times greater than that for the wood aerogel (WA). The longitudinal (along the fibres) and transverse (across the fibres) thermal conductivity of DWS (0.122 & PLUSMN; 0.006 and 0.081 & PLUSMN; 0.002) showed 15.3 % and 27.7 % decrease respectively with respect to native wood. TGA analysis revealed the improvement in thermal stability after the silanisation of the aerogel. Acoustic properties showed similar to 80 % sound absorption over a frequency range of 1500-3000 Hz for DWS with a maximum sound absorption coefficient of 0.8 at high frequency range. Thus, the current work paves the way to replace the petroleum-based aerogels currently used for such multifunctional applications being ecofriendly and biodegradable in nature.