Investigation on the influence of Hemicellulose on time dependent behaviour of wood

As known the stress strain relationship in wood is dependent on time, humidity and temperature, including their variations and history. This study focuses the attention on the influence of hemicelluloses on the time dependent behaviour and mechanosorption effects of wood. The experiments were performed on two sets of thin clear samples of Spruce (Picea abies Karst.). The first used natural non-treated wood as a reference while hemicelluloses in the second one were removed totally. Specimens were tested by means of micro-tensile device equipped with a climatic chamber able to conditioning sample environment. Temperature was set at 20°C while cyclical RH changes from 30% up to 75% during application of load. Loads applied were respectively 20 and 40% of ultimate tensile strength. After mechanical test the specimens have been analysed by means of IR spectrometry in order to evaluate the effectiveness of hemicelluloses removal from the sample.