Investigations on wood treatment by eco-friendly hydroxypolyurethanes

Abstract

Dimensional stabilisation is a crucial property for using wood in most applications. Therefore an isocyanate-free route is proposed, based on the reaction of various diamines with dicarbonates obtained by addition of two glycerol carbonates moieties on a linker. For the initial experiments, the mildest conditions to perform the reaction are researched with model mono- and polyamines without wood: solvent, temperature, number of equivalent and regioselectivity were investigated. Subsequently, beech wood blocks were impregnated by a double vacuum process involving cyclic carbonates and then polyamines. The key step was a polycondensation performed in the beech blocks after the monomers had been impregnated. Resistance of treatment to leaching, anti-swelling efficiency and decay durability versus Poria placenta were evaluated. Results were promising with ASE values of about 70% for a weight gain of approximately 30% after leaching. Biological tests indicated also an improvement of resistance to fungal decay of beech wood.

Keywords

Dimensional stabilisation Anti-swelling effect Wood preservation Glycerol carbonate Isocyanate-free polyurethanes NIPU

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