MECHANICAL AND COLOUR PROPERTIES OF RUBBERWOOD BASED ON THE VARIATION IN WOOD SHRINKAGE

Abstract

Defects in rubberwood is a major problem in the rubberwood industry of Thailand. It was detected during the drying process of rubberwood which caused bow and crook deformations. The current study presented a model that described the change in the magnitude of bow and crook between two moisture contents below the fiber saturation point. The longitudinal shrinkage in the experimental samples was obtained at the moisture content range from 16% to 8%. The model showed that the variation in longitudinal shrinkage coefficient over the cross-section and along the sample could explain most of the changes in bow and crook of
the lumber. In addition, it was possible to identify evenly-curved bow and crook. The least value of root mean square error was at 0.115 and standard error of 0.130 for sample 3A1 and root mean square error of 0.179 and standard error at 0.202 for sample 7B3 indicated that these samples had the best model predictions. The model was able to predict the changes in bow better than the changes in crook. Both mechanical and colour properties were comparable to the work of others.