Title
Chemical changes in fir wood from old buildings due to ageing
Authors
FRANTISEK KACIK PAVEL SMIRA DANICA KACIKOVA LADISLAV REINPRECHT and ANDREA NASSWETTROVA

Received February 8, 2013
Published Volume 48 Issue 1-2 January-February
Keywords historic wood, fir, ageing, lignin, cellulose, hemicelluloses, size exclusion chromatography

Abstract
Wood is a biological material and changes in its molecular structure during exposures usually have a negative influence on its strength and other mechanical and physical properties. In this work, wet chemical and physico-chemical methods have been used to determine the changes in the cellulose, hemicelluloses, lignin and extractives of the 108 to 390-year old visually undamaged fir wood taken from beams situated in the Rychvald castle in Czech Republic. Natural ageing of the fir wood without activity of biological agents caused a significant increase of the extractives content (twofold, or for the oldest beam, even fourfold) and a decrease of the hemicelluloses (by maximum 24%), while the amounts of lignin and holocellulose were quite stable (decreased only by 4%). The molecular weights, respectively, degrees of polymerization, were stable in cellulose, decreased in hemicelluloses, while in lignin increased due to condensation reactions.