ACCELERATED WEATHERING OF WOOD SURFACES MODIFIED BY CHROMIUM TRIOXIDE

Samples of Hevea brasiliensis (Rubber wood) treated with dilute aqueou s solution of chromium trioxide along with untreated specimens were ex posed to artificially generated weathering conditions. Results show a severe deterioration of wood surfaces in untreated specimens which is mainly due to loss of lignin. IR spectroscopic analysis indicated an i ncrease in the concentration of carbonyl chromophoric functional group s in exposed wood surfaces, whereas aromatic functional groups due to lignin decreased with irradiating time. Treatment of wood with an aque ous solution of chromium trioxide was found to restrict surface deteri oration remarkably. DRIFT spectra obtained from exposed wood surfaces provide direct evidence of modification and stabilisation of lignin du e to formation of a photo-stable complex in treated samples.