Eco-friendly fabrication of a delignified wood‑calcium alginate aerogel with improved mechanical properties for efficient thermal insulation and flame retardancy

Int J Biol Macromol. 2024 Dec 9:287:138561. doi: 10.1016/j.ijbiomac.2024.138561. Online ahead of print.

Abstract

Wood based composites with low density and great flame retardancy are increasingly required as sustainable and low-carbon building materials for energy conservation. In this work, the symbiosis between bio-based calcium alginate (CaA) and delignified wood was fabricated to form delignified wood-CaA aerogel composites. The density of the delignified wood@CaA sample was dropped to only 89 kg/m3 from 120 kg/m3 of the control wood. In addition, its tensile strength, elongation at break, and bending strength reached 16.9 MPa, 4.6 %, and 40.2 MPa, which was increased by 128.4 %, 109.1 %, and 31.8 %, respectively compared to that of control wood. During either heating or cooling, the delignified wood@CaA sample always showed better thermal insulation than the control wood, moreover, it can be developed as an infrared stealthy material. Furthermore, the delignified wood@CaA aerogel reached the limiting oxygen index of 59.2 %, and it was self-extinguished immediately after leaving ignitor in the vertical burning test. In the cone calorimeter test, the total heat release and total smoke production of delignified wood@CaA aerogel decreased by 27.6 % and 71.4 % compared to that of the control wood, respectively. In summary, the light-weighted delignified wood@CaA aerogel composite with superior performance is an ideal material used in sustainable and low-carbon building.

Keywords: Delignified wood; Flame retardancy; Heat insulation.