| Summary: | 碩士 === 國立宜蘭大學 === 森林暨自然資源學系碩士班 === 104 === Densification of Taiwania and China fir by compression along its transversal directions was carried out to enhance physical and mechanical properties. Relative humidity (RH) conditionings, pre-treatments and compression set ratios (CSR) were applied. Densities of Taiwania and China fir increased about 9% to 55% and 8% to 58%, respectively by CSR 16%, 28% and 40%. Achievement of surface densification can be observed by comparing density profile before and after treatments. Surface densified showed increasing density in beneath few millimeters from the surface and broader high density peak by higher CSR. Densification reduced moisture content of Taiwania from 12.54% to 8.82% and China fir from 11.71% to 8.67% on the average. Improvement of density induced increasing of the others properties like static hardness, modulus of elasticity (MOE) and modulus of rupture (MOR). MOE and MOR of Taiwania and China fir are increased about 39%, 43% and 31%, 30%, respectively. Static hardness increasing of Taiwania and China fir are about 38% and 43%, respectively. Physically, the color of the wood’s surface was found darker and smoother after surface densification. Physical and mechanical properties are improved except thickness swelling, which were greater after densification, spring-back also occurred after press opened and samples conditioned at RH 65%. Yield percentage of Taiwania densification is about 74% and China fir is 83%, accordingly, China fir showed higher opportunity for densification.
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