Wetting of Araucaria angustifolia e Pinus elliottii samples after thermal treatment and aging

Contact angle measurements, along with those of density, were performed in order to better understand the wetting characteristics of two types of wood; from Araucaria angustifolia and Pinus elliottii, under controlled experimental conditions. The use of a common thermal analysis technique, differential scanning calorimetry (DSC), did not lead to accurate conclusions about surface changes that occur with wood samples while increasing the temperatures to 200 ��C. However, the results obtained here showed that the wettability of the wood samples decreased when the temperature reached 200 ��C, and also, varied with time, sample type and fracture region. It did vary with time, sample type, and fracture region. A dramatic change in the wettability for both wood samples was verified from 120 ��C to 140 ��C, even before any considerable difference in mass loss and apparent density had been noticed. These measurements enable one to clearly distinguish between wood species which were thermally treated to 200 �� C.
This work was supported by CAPES, CNPq and FAPESP