Effect of Temperature and Clamping during Heat Treatment on Physical and Mechanical Properties of Okan (Cylicodiscus gabunensis [Taub.] Harms) Wood

초록

The objective was to evaluate the effect of temperature and clamping method during heat treatment on the properties of high density Okan wood. Heat treatment of sapwood and heartwood was conducted using an electric oven with a programmable controller at 160 degrees C, 180 degrees C, 200 degrees C, and 220 degrees C for 2 h. Physical and mechanical properties were compared before and after the heat treatment process. The color change (Delta E-star), weight loss, and volume shrinkage increased with increasing temperature, whereas the equilibrium moisture content (EMC) and water absorption (WA) decreased in both types of wood. The wood density was not affected by temperature, and the magnitude of Delta E-star in sapwood was the highest, while the magnitude of weight loss, volume shrinkage, EMC, and WA in heartwood was higher than in sapwood. The clamping method affected Delta E-star in heartwood only, while the weight loss, volume shrinkage, EMC, and WA was affect in both types of wood. A significant reduction in the mechanical properties occurred after heat treatment at 200 degrees C and 220 degrees C. The reduction of MOR, MOE, and shear strength in heartwood was greater than in sapwood, while the compressive strength reduction in sapwood was the highest.

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