Improvement of wood properties by impregnation with multifunctional monomers



Southern pine samples with different dimensions and bulk densities were impregnated with the multifunctional monomer ethyl α-hydroxymethylacrylate (EHMA) and 5 mol % of fluorinated or nonfluorinated crosslinking agent. The maximum impregnation yield (105% by weight) was achieved under vacuum with good improvement of water repellency.

Impregnation with EHMA plus another multifunctional monomer 2-vinyl-4,4-dimethyl-2-oxazolin-5-one (vinyl azlactone) was carried out to improve the mechanical properties of wood samples. Water repellency was also improved depending on the amount of vinyl azlactone in the monomer solution. A maximum of 41% antiswell efficiency (ASE) was obtained by impregnation with a 9 : 1 w/w mixture of EHMA and vinyl azlactone. Improvements of 38–54% in impact strength and 27–44% in compression modulus were achieved depending on the relative amount of vinyl azlactone incorporated. FT-IR and solution or solid-state NMR spectroscopy were used for chemical characterization of the polymers themselves and the wood-polymer composites.