LACK OF DIMENSIONAL STABILITY IN CROSS-LINKED WOOD-POLYMER COMPOSITES

While many polymers which are polymerized in situ impart desirable pro perties to the final composite, they do not react with the cell wall, and their dimensional stability is therefor poor. In an attempt to ove rcome this deficiency, we studied the combination of polyglycols cross linked with dimethylol dihydroxyethylene urea (DMDHEU) in ponderosa p ine. We hypothesized that, if the DMDHEU could be cross-linked with bo th the wood and the polyglycol, the bulking effect might be rendered n on-leachable and dimensional stability achieved. However, we found tha t the cross-linked polyglycols showed increased swelling in some cases , resulting in decreased dimensional stability. The effect was related to the specific compounds employed and their loading in the wood, res ulting in failure in some cases where high retentions were employed.