Differential response of wood to dry air thermal treatment (DATT) and soy oil thermal treatment (SOTT)
Thermal treatment is an alternative to chemical modification method which has been used to some extent in improving timber quality. In order to get the maximum benefits possible without compromising the various end-use quality requirements of timber, several possibilities have been and are still being investigated in relation to this technique. Clear wood samples (19 x 19 x 150mm) of kiln-dried red pine (Pinus resinosa) were subjected to dry air thermal treatment (DATT) and soy oil thermal treatment (SOTT) separately over a time period of 2 hours and 4 hours. Hygroscopy and swelling were determined by soaking in water for 24 hours at room temperature while wettability was determined by the sessile drop contact angle measurement method. The mechanical properties were determined by 3-point bending test using Zwich testing machine model Z050. The dry air thermally treated wood were significantly higher in hygroscopy, swelling and modulus of elasticity but significantly lower in modulus of rupture and modulus of toughness than those treated in soy oil medium. No significant difference in wettability was observed between DATT and SOTT indicating that the treatment medium did not contribute significantly to the wettability changes in the wood.