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  • Author: P. Gérardin x
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Summary

Grafting of perfluoroalkyl ethanol derivatives on spruce meal (Picea abies) and beech blocks (Fagus sylvatica) was performed using 4,4′-diphenylmethane diisocyanate (MDI). The formation of urethane bonds between MDI, perfluoroalkyl ethanol and wood allowed to increase wood's dimensional stability. Contact angle measurements were also performed. θ values obtained for wood grafted with perfluoroalkyl ethanol derivatives were greater and did not decrease with time compared to those obtained with unmodified wood.

Summary

The aim of this work was to study the wettability and chemical composition of heat-treated wood. Heat treatment was performed at 240°C under inert atmosphere on four European wood species (pine, spruce, beech and poplar). Contact angle measurements before and after treatment indicated a significant increase in wood hydrophobicity. Advancing contact angles of a water drop were in all cases systematically higher for heat-treated than for untreated wood. Chemical modifications of wood after heat treatment were investigated using FTIR and 13C NMR analysis. FTIR spectra indicated little structural change which could be attributed either to carbon-carbon double bond formation or to adsorbed water. NMR spectra also revealed little chemical change except for the degree of cellulose crystallinity which was considerably higher in heat-treated wood and could explain the higher contact angles.

Summary

Polyglycerol (PG), an agricultural by-product of diester industry, was reacted with maleic anhydride (MA) to give heat curable compounds which are useful for impregnating wood to improve biological resistance, dimensional stability and strength. The relationships between reaction conditions of polyglycerol/maleic anhydride (PG/MA) adduct treatment and performance of treated solid wood were investigated. Conditions recommended for producing PG/MA treated wood durable for a long time are vacuum/pressure impregnation of aqueous solutions of PG/MA adduct (30%) in the presence of 2-butanone peroxide (2%) and cobalt naphthenate (2%).