熱處理對柳杉及山毛櫸平切單板之物理機械性質影響

Effects of Heat Treatment on Physicomechanical Properties of Japanese Cedar and Beech Sliced Veneers

錢易琦(Yi-Chi Chien) ； 楊登鈞(Teng-Chun Yang) ； 洪克昌(Ke-Chang Hung) ； 吳志鴻(Jyh-Horng Wu)

《林產工業》 32卷4期 (2013/12) Pp. 213-225

https://doi.org/10.6561/FPI.2013.32(4).3

摘要

本研究係利用不同溫度（120-260℃）及氣體環境（空氣及氮氣）對柳杉（Cryptomeria japonica）及山毛櫸（Fagussylvatica）平切單板進行熱處理，同時，利用萬能強度試驗機、X－ray繞射儀及色差計等儀器，探討熱處理對平切單板理學機械性質及結晶度之影響。試驗結果顯示，不論在空氣或氮氣環境下進行熱處理，木材之質量損失率及體積收縮率隨著熱處理溫度之提高而增加。另外，經由浸水試驗結果亦得知，當熱處理溫度為260℃時，木材具有較高之疏水性及尺寸安定性。至於機械性質方面，於空氣環境下，當熱處理溫度超過200℃時，試材之抗彎強度保留率則有顯著性的下降；而於氮氣環境下，當熱處理溫度達260℃時，試材之抗彎性質最差。而在木材表面性質方面，於空氣環境或氮氣環境下，熱處理木材之表面顏色分別自180℃與200℃開始呈現深色化，此外，試材表面會隨熱處理溫度增加而呈現較平滑之外表。另一方面，試材經過熱處理後，會因其非結晶區之多醣類成分的降解，而增加試材結晶度，但當熱處理溫度達260℃時，因纖維素結晶區開始降解，會進而降低試材結晶度。

關鍵字

熱處理 ； 柳杉 ； 山毛櫸 ； 平切單板 ； 物理機械性質

並列摘要

In this study, Cryptomeria japonica (Japanese cedar) and Fagus sylvatica (Beech) sliced veneers were heated at different temperatures (120-260℃) under air or nitrogen atmosphere. Effects of heat treatment on physicomechanical properties of sliced veneers were evaluated by universal testing machine, X- ray diffractometer, and color difference meter, etc. These results showed that the mass loss and volume shrinkage percentage of the heat treated sliced veneers increased with increasing heat treatment temperature regardless of gas atmosphere. According to the results of soaking test, sliced veneers exhibited better dimensional stability and hydrophobic properties after heat treatment. When the heat treatment temperature exceeded 200℃ under air atmosphere, the modulus of ruptures (MOR) of sliced veneers decreased significantly. In contrast, the veneers exhibited the lowest flexural properties at 260℃ under nitrogen atmosphere. The color of sliced veneers darkened after 180℃ and 200℃ treatment under air and nitrogen atmosphere, respectively. Additionally, the surface of heated sliced veneers showed smooth significantly with increasing heat treatment temperature. On the other hand, the crystallinity of heat treated sliced veneers increased with an increase of heat treatment temperature due to the degradation of the polysaccharides in the amorphous region. However, when heat treatment temperature reached 260℃, a significant decrease of crystallinity of sliced veneers was observed because the cellulose degraded in the crystalline region.

並列關鍵字

Heat treatment ； Japanese cedar ； Beech ； Sliced veneers ； Physicomechanical properties