No abstract

This research was aimed at determining the surface roughness and surface brightness properties of Scots pine (Pinus sylvestris L.) wood samples to which water-based varnishes were applied after thermo-mechanical densification and heat treatment. Samples; after densifying by compression in the radial direction at two different rates (20 and 40 %) and two different temperatures (110 and 150 °C), samples were subjected to 2 h of heat treatment at 190, 200, and 210 °C. Then, surface of the samples was varnished with one-component (OCW) and two-component (TCW) water-based varnishes. The changes occurring in surface roughness and surface brightness of the samples were determined according to the basis of TS 2495 EN ISO 3274, TS 6212 EN ISO 4288 and TS EN ISO 2813. According to results of the research, surface roughness decreased and surface brightness increased in densified samples. On the other hand, an increase in the heat treatment temperature led to an increase in surface roughness and a decrease in surface brightness. Also, regarding the effect of varnish type on both surface roughness and surface brightness, better results were obtained in the surface OCW applied compared to those TCW applied.

The effects of thermomechanical densification (TMD) and heat treatment on density and Brinell hardness of Scots pine (Pinus sylvestris L.) and Eastern beech (Fagus orientalis L.) woods were investigated. Samples were densified using a specially designed hydraulic press with target compression ratios of 20 and 40%, and at 110 °C and 150 °C. Then, the heat treatment was applied to the samples at three different temperatures. To determine whether the changes occurred because of technological properties, tests of Brinell hardness and air-dry density were conducted. Increases of 42 and 35% were obtained for the density of Scots pine and beech samples, respectively. After the densification process, increases in radial and tangential hardness values were obtained. Decreases were observed in the density and hardness values of the samples because of the increase in temperature during heat treatment. After heat treatment, there were 4 and 5% decreases in the respective densities of Scots pine and beech, and decreases in their radial and tangential hardness values.

No abstract

This study investigated the effects of densification and heat post-treatment on the Janka hardness and microscopic structure of relatively low-density Uludağ fir, linden, and black poplar woods. Wood samples were densified with compression ratios of 25% and 50% at 100 °C and 140 °C, respectively. Heat post-treatment was then applied to the samples at 185 °C and 212 °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 °C, the hardness values were higher in the tangential direction, whereas the samples compressed at 100 °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 °C with compression ratio 50% and high heat posttreatment temperature.