Dimensional stabilization of wood by microporous silica aerogel using in-situ polymerization

In this paper, a method for dimensional stabilization of wood through bulk hydrophobization was investigated using a sol–gel process resulting in in-situ formation of microporous SiO 2 aerogel. Two different wood species, beech ( Fagus sylvatica ) and Scots pine ( Pinus sylvestris ) were investigated. The incorporation of microporous silica aerogel inside the cell wall and lumen was verified by scanning electron microscopy, energy dispersive spectrometry and Fourier-transform infrared spectroscopy. A leaching test using paper as model material proved the bonding of the aerogel to the cellulose component of the cell wall, which indicates a long-lasting effect of the treatment. The modification of wood with silica aerogel significantly improved its hygroscopicity and dimensional stability, decreased the equilibrium moisture content and water uptake beside a low weight percent gain. Permeability was reduced as a result of the silica aerogel deposition in the macro- and micropores of the modified wood. The treatment resulted in an obvious colour change as well.