Thermo-Vacuum Modification of Teak Wood from Fast-Growth Plantation

Sawnwood of teak (Tectona grandis L.f.) from a Costa Rica plantation was thermally treated at different process conditions using thermo-vacuum technology. The main objectives of the study were to find the optimal combination of the process parameters, i.e. temperature (T), and duration (t), in order to minimise the colorimetric difference between sapwood and heartwood, and to evaluate the influence of the treatment on the modification pattern of physical properties of the material. The resulting mass loss (ML), hygroscopicity (H), dimensional stability (ASE), and lightness (L) were measured and compared. As expected, the temperature (T) is the main parameter influencing the extent of modification. The measured ML values turned out to be moderate even at high T values if compared with other hardwoods. The temperature range between 180 degrees C and 190 degrees C minimizes the colorimetric difference between treated sapwood and not treated heartwood.