Improvement of the biological performance and dimensional stability of two tropical woods by thermal modification
M M González-Peña
Pink cedar wood and rubberwood were thermally modified at 230°C in air for 4 h or for 8 h, and then subjected to bending, compression and hardness tests to evaluate the effect of the treatment on these mechanical properties. The biological performance of the modified wood was also determined, according to EN113, and the dimensional stability measured by means of the anti-swelling efficiency. The thermal modification afforded increased decay resistance and improved the dimensional stability of these tropical woods, at the expense of significant reductions in the Modulus of Rupture and the Work at Maximum Load in the bending test. The reduction in bending strength and in resilience was not significant at the limit of proportionality though; the modified material is hence deemed as suitable for non-structural applications where the occurrence of sudden loads shall not lead ultimately to human harm. Color changes resulted in aesthetic enhancements on these two wood species, particularly so in pink cedar wood. These color changes were readily exploited for the multivariate prediction of all properties studied in this work, including the decay resistance of thermally-modified wood.