1 research outputs found
The Effects of Densification and Heat Post-Treatment on Hardness and Morphological Properties of Wood Materials
This study investigated the effects of densification and heat
post-treatment on the Janka hardness and microscopic structure of
relatively low-density Uludag fir, linden, and black poplar woods. Wood
samples were densified with compression ratios of 25\% and 50\% at 100
degrees C and 140 degrees C, respectively. Heat post-treatment was then
applied to the samples at 185 degrees C and 212 degrees C for 2 h. The
hardness in the radial and tangential directions was determined, and
morphological changes in the cell structures were analyzed using
scanning electron microscopy (SEM). The hardness values in the radial
and tangential directions of the densified samples increased depending
on the compression rate and treatment temperature. The hardness values
in both directions were higher in the 50\% compressed samples. For
samples compressed at 140 degrees C, the hardness values were higher in
the tangential direction, whereas the samples compressed at 100 degrees
C were higher in the radial direction. After the heat post-treatment
process, the hardness values of all samples decreased. As the treatment
temperature increased, more adverse effects on the hardness was noted.
According to the SEM analyses, the densification and heat post-treatment
deteriorated the cell structure of the samples. The more cell
deformation was observed in the samples densified at 100 degrees C with
compression ratio 50\% and high heat post-treatment temperature