Weathering characteristics of wood treated with water glass, siloxane or DMDHEU

Abstract

Specimens of Scots pine sapwood (Pinus sylvestris) and beech wood (Fagus sylvatica) were treated with a sodium water glass solution, an amino-alkyl-functional oligomeric siloxane and 1,3-dimethylol-4,5- dihydroxyethylene urea (DMDHEU). The specimens were exposed outside without ground contact for 24 months. Colour measurements during outside exposure showed a discoloration of all wood specimen surfaces. FTIR spectroscopy displayed lignin degradation of all specimens during the initial exposure time. Chemical treatments decelerated fungal infestation of wood, while their effect on lignin degradation was not discernible. SEM studies revealed that fungal infestation was affected by the different treatments. The untreated specimens showed radial penetration of fungal hyphae through the pits. Only superficial infestation and no radial penetration were visible at water glass and siloxane treated specimens. A significantly reduced radial penetration of fungal hyphae was exhibited at DMDHEU treated specimens. Fungal infestation through the pits was not visible. © Springer-Verlag 2010.