Consolidation of fir wood by poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) treatment: study of surface and mechanical characteristics

The ability of poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVBVA) to consolidateFir wood was studied in terms of the surface and mechanical properties" changes. Two variableswere considered to treat the wood: (i) the concentration (5 and 10 wt.%) of PVBVA solutions and (ii)the method of application (brushing and immersion). The presence of PVBVA on the wood surfaceswas confirmed by infrared spectroscopy. Surface roughness measured by optical profilometry did notreveal changes in the topography of the samples, and appropriate visual appearance was confirmed.Contact angle measurements showed that a droplet of the 10%-PVBVA solution needed ~50 s to reachthe same contact angle decreasing rate as that measured for the 5%-PVBVA solution, suggestingthere was some kind of induction time till the spreading process was no longer controlled by theviscosity, but by the solution-wood interactions. Water contact angle (WCA) measurements proved amore hydrophobic surface of the PVBVA-treated samples, compared to untreated wood. Mechanicalcharacterization of the samples was done macroscopically by a three-point bending test and locally bythe Shore D and Martens hardness (MH). Only results from MH experiments provided comparativeresults, indicating that treatment with PVBVA solutions increased wood hardness locally, beingenhanced with solution concentration. The best surface mechanical properties were obtained for thesamples immersed in the 10%-PVBVA solution.

Consolidation of fir wood by poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) treatment: study of surface and mechanical characteristics Articles