CHEMICAL ACETYLATION TREATMENT IN RADIATA PINE WOOD

When woody cell wall is saturated with acetic anhydride, the free hydroxyl groups present on cellulosic structures are replaced. Thus, the capillary spaces are filled with acetyl groups and this replacement avoids further reactions with water or enzymatic degradation provoked by rot fungi. So, the death of different fungi is produced by the lack of food. It has been observed too that this chemical modification has improved the dimensional stability and the resistance to xylophages agents. Under this premise, we conducted a research in order to test acetylation of Pinus radiata D. Don wood as a strategy for their protection. An experimental methodology was used under laboratory conditions to determine the effect of the acetylation on some properties such as: water content; density, water uptake; dimensional stability and biodegradation provoked by rot fungi in Pinus radiata D. Don. Two immersion times of pine wood on acetic anhydride and two times in autoclave were tested (30 and 60 minutes). Thus, observed weight gains ranged between 6 and 20%. We also noted the improvement of other properties such as: a) the resistance to the degradation provoked by brown rot fungi, because in treated wood the weight losses ranged between 1.38% and 17.43% in comparison to control samples which reached 64.94% when the same fungi strain was used; b) when a white rot fungi strain was tested, weight losses ranged between 2.96% and 9.12% for acetylated samples in comparison to untreated pieces which showed 17.9% after 4 months of incubation. Furthermore, the dimensional stability and water absorption capacity improved.