Lack of Dimensional Stability in Cross-Linked Wood-Polymer Composites

While many polymers which are polymerized in situ impart desirable properties to the final composite. they do not react with the cell wall, and their dimensional stability is therefor poor. In an attempt to overcome this deficiency, we studied the combination of polyglycols cross linked with dimethylol dihydroxyethylene urea (DMDHEU) in ponderosa pine. We hypothesized that, if the DMDHEU could he cross-linked with both the wood and the polyglycol, the bulking effect might be rendered non-leachable and dimensional stability achieved. However, we found that 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, resulting in failure in some cases where high retentions were employed.