Swelling and shrinkage characteristics of Kapur (Dryobalanops aromatica) wood in three anatomical directions

Abstract

Wood is a hygroscopic material. When wood is below the fibre saturation point (FRP), it induces the dimensional changes. Dimensional changes in wood are a major source of defect in finishing product that can reduce the quality of the product itself. Shrinkage and swelling of wood occur as a result of moisture content change in atmospheric humidity. Swelling and shrinkage of wood could not be avoided, therefore it is important to study the properties so the effects can be minimized. This study was conducted to determine the variability of swelling and shrinkage characteristics of Kapur (Dryobalanops aromatica) in three different anatomical directions; radial, tangential and longitudinal. For swelling test, Kapur samples were immersed in the water while for shrinkage, the samples were dried in the oven. Results from the study showed that percentage of swelling and shrinkage vary in each direction. The samples swell and shrink the most at the tangential direction compared to the other two directions. Meanwhile, the swelling-shrinkage in the longitudinal direction can be considered as negligible. Result shows that Kapur has the mean swelling percentages of 4.20%, 1.99% and 0.33% in tangential, radial and longitudinal, respectively. As for the shrinkages, the mean percentages in tangential, radial and longitudinal directions were 4.46%, 2.81% and 0.21%, respectively.