The study of selected properties of pine wood (Pinus sylvestris L.) subjected to acetylation

The study of selected properties of pine wood (Pinus sylvestris L.) subjected to acetylation. In the paper pine wood was subjected to acetylation with acetic anhydride and mixture of acetic anhydride and glacial acetic acid (50:50)v/v. After modification process density, WPG index, water absorbability, volume swelling and colour of wood were carried out and compared with results obtained for unmodified pine wood. Based on the obtained results the density of acetylated pine wood was increased for each group of samples. The highest WPG index was obtained for previously dried wood modified with acetic anhydride (15.6%) or mixture of acetic anhydride and glacial acetic acid (10.5%). Acetylation process with acetic anhydride or mixture of acetic anhydride and glacial acetic acid of samples, which were extracted (in chloroform-ethanol 93:7w/w mixture) and dried before modification, had beneficial effect on water absorbability of pine wood. These samples after 1001h (about 42 days) of soaking in water reached the lowest values of water absorbability (about 94%). Moreover, the volume swelling were significantly reduced for samples after double impregnation cycle (both in case of modification with acetic anhydride or mixture of acetic anhydride and glacial acetic acid). Wood after acetylation process was slightly darker than unmodified pine wood. Acetylation of samples, which were dried and soaked in DMF before modification, caused significant darkening of pine wood. The obtained colour was similar to colour of furfurylated wood (Kebony wood) or some of exotic species.