Processing renewable corks into excellent thermally stable, flame-retardant and smoke-suppressant composite materials by respiratory impregnation method

Abstract

Recently, lightweight cork-based materials with excellent thermal stability and flame retardant have attracted great attention. New lightweight cork-based materials with improved thermal stability and flame-retardant characteristics were prepared using facile methods to deepen the application of cork materials in the indoor environment of buildings. In this work, silica aerogel composite corks (CoSiAe-S and CoSiAe-V) were quickly prepared by immersing corks of different tree species in the silica aerogel slurry by respiratory impregnation method. The structure, porosity and thermal stability of the composites were studied using infrared spectroscopy, sorption isotherms and thermogravimetric analytical measurements. The flame retardant and smoke suppression properties of particleboards produced from silica aerogel composite corks were also discussed. Results show that the silica aerogels are fixed in cork cells to form a network of stratified ‘pore inside a pore’ structure. Quercus suber corks (Cor-S) show better thermal stability than Quercus variabilis corks (Cor-V). The silica aerogel treated corks show good thermal stability. The flame retardant and smoke suppression properties of particleboards produced from silica aerogel composite corks (CoSiAe-SP and CoSiAe-VP) are significantly improved. For instance, the total heat release reduced by 26.46 % and 31.33 %, and the total smoke release decreased by 85.60 % and 52.04 %. The physical insulation and adsorption effect of silica aerogels in cork cells are considered to be the reasons for the improved flame retardant and smoke suppression.