木材之化學改質及其膠合性之研究（III）－乙醯化處理對木材尺寸安定性及力學性質之影響

Chemically Modified Wood and Its Gluing Properties (III)-Effects of Acetylation on Dimensional Stability and Mechanical Properties

劉正字(Cheng-Tzu Liu) ； 李文昭(Wen-Jau Lee) ； 夏以淳(I-Chun Hsia)

《林產工業》 19卷2期 (2000/06) Pp. 229-239

https://doi.org/10.6561/FPI.2000.19(2).8

摘要

本研究乃利用醋酸酐對紅柳桉、紅櫟木及杉木等三種木材行乙醯化化學改質，探討不同乙醯化處理條件對木材尺寸安定性之改良效果及其對木材力學性質之影響。由其結果得知，木材在乙醯化處理過程中之注入率主要受樹種所影響，比重較低者有較高之注入率。而注入處理之壓力及時間與其注入率並無明顯關係存在，三種試材經乙醯化化學改質後之重量增加百分率（WPG）約在17.9%至22.7%之間，紅櫟木之WPG值有隨處理時間延長或處理壓力增加而略為提升之趨勢。乙醯化試材之平衡含水率均較未處理材降低，浸水時之吸水率及體積膨脹率亦降低，紅柳枝、紅櫟木、杉木浸水5天後之抗體積膨脹效能分別為74.4~82.0%、73.7~80.1%、60.4~69.0%。吸濕時之吸濕膨脹率亦明顯降低，三種試材間則以紅櫟木之抗吸濕膨脹效能高於其它兩者。乙醯化處理試材之硬度均較未處理材為高，靜曲彈性係數則下降，靜曲破壞強度除紅柳桉有提高之現象外，紅櫟木及杉木均明顯降低。

關鍵字

化學改質 ； 乙醯化 ； 尺寸安定性 ； 膠合性

並列摘要

This study investigated the effects of acetylation of red lauan (＂Shorea spp.＂), red oak (＂Quercus rubra＂) and China fir (＂Cunninghamia lanceolala＂) with various treatment conditions on the dimensional stability and mechanical properties of wood. The results were summarized as follows: The loading rate of acetic anhydride was decided mainly by wood species, wood with lower specific gravity had the higher chemical loading rate. But there was no clear relationship between the chemical loading rate and impregnation pressure or time. Weight percent gain (WPG) of all these three wood specimens after chemical modification of acetylation ranged from 17.9% to 22.7%. WPG of red oak increased with increasing the impregnation time or pressure. Equilibrium moisture contents of the acetylated woods were lower than those of untreated woods. Acetylated woods had lower water absorption and volumetric swelling when soaked in water, the value of anti-swelling efficiency of volume (ASE) of red lauan, red oak and China fir after five days soaking in water were 74.7%-82.0%, 73.7%-80.1% and 60.4%-69.0%, respectively. Hygroscopic swelling of volume of acetylated wood was reduced too, and red oak had the highest ASE. The hardness of wood after acetylation increased, but the modulus of elasticity decreased, the bending strength of red oak and China fir reduced significantly, while red lauan increased slightly.

並列關鍵字

Chemical modification ； Acetylation ； Dimensional stability ； Gluing property