Microwave irradiation of glycerol carbonate allows formation of glycidol, which readily polymerizes to form polyglycerol under mild conditions comparatively to the classical polyetherification reaction involving high temperature and basic conditions. Analysis of the crude reactional mixture indicated the presence of low-molecular weight oligomers constituted mainly of di, tri, and tetraglycerols with small quantities of higher molecular weights oligomers. Molecular size distribution was relatively similar to that of polyglycerols obtained under basic condition, even if these latter contained slightly higher amounts of high-molecular weight oligomers. Structure of oligomers differs slightly according to the conditions of polymerization, and polyglycerols are obtained under microwave activation containing higher contents of cyclic isomers, whereas polyglycerols obtained under basic conditions contain more ramified isomers.
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.
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