Manufactures and Properties of Cryptomeria japonica and Acacia confusa Heat-treated Woods

本研究係將含水率為12%之柳杉（Cryptomeria japonica）與相思樹（Acacia confusa），以炭化爐並在N2環境下進行熱處理，探討最終處理溫度（130、160、190、220、250及280℃）、持溫時間（1、2及3 hr）、木材厚度（30、50及70 mm）與升溫速率（10、20及30℃/hr）等熱處理變因，尋求最佳熱處理條件，試驗性質包括質量損失、密度、平衡含水率、色差值、粗糙度、尺寸安定性、硬度、抗彎強度，並進行傅立葉紅外線光譜（FT-IR）分析、元素分析（EA）及熱重量分析（TGA）等。並分析不同溫度熱處理柳杉與相思樹木醋液之基本性質與有機成分。此外，並以尿素膠與聚醋酸乙烯乳膠進行膠合，及以二液型聚胺基甲酸酯塗料與硝化纖維素拉卡進行塗裝，並以實際土壤埋木試驗評估熱處理材之膠合、塗裝與耐腐性。 試驗結果顯示，柳杉與相思樹材在厚度50 mm，以升溫速率10℃/hr升至190℃，分別持溫2與3 hr熱處理後，可獲得較佳尺寸安定性質，且具有較佳硬度與靜曲抗彎強度。依本研究所設定實驗條件下，經顏色變化及FT-IR分析結果，柳杉材之熱處理程度約達厚度25 mm左右，而相思樹材約達厚度20 mm左右。 不同溫度熱處理柳杉與相思樹木醋液之收率、色值與比重會隨處理溫度之升高而增加，比重介於0.983－1.030，pH介於2.55－3.43之間，有機酸含量在0.06－9.11%間；經由GC-MS分析結果木醋液有機成分會隨溫度升高而增加，柳杉木醋液以130、160與190℃熱處理其有機成分以isoledene等抽出物成分為主，而以220℃熱處理者酸性物質會大量生成且以acetic acid為主，而酚性物質則在280℃熱處理過程中大量生成，且以2-methoxy-phenol與2-methoxy-4-methyl-phenol較多。相思樹木醋液以130℃熱處理者之有機成分以脂肪酸類為最多，其他溫度處理者之酸性物質均以acetic acid含量為最多，以160℃熱處理木醋液中性物質以andrographolide等抽出成分為主，190℃以上處理者則以3-furaldehyde含量為較多；以220℃以上處理者開始產生酚性物質，且含量會隨處理溫度之升高而增加，並以2,6-dimethoxy-phenol與mequinol最多。 又柳杉與相思樹熱處理材以UF與PVAc為膠合劑之常態剪力強度較未處理材者為低。又柳杉與相思樹熱處理材之PU與NC拉卡塗膜附著性與耐衝擊強度與未處理材者無顯著差異，且冷熱循環之耐久性優良，並較未處理材者有較高光澤度保留率及耐光性，又經土壤埋木耐腐朽試驗，熱處理材之耐腐朽性較未處理材者為佳。In this study, the heat treatments of Cryptomeria japonica and Acacia confusa woods with moisture content of 12% were performed using steel kiln under N2 atmosphere. The parameters of heat-treated conditions such as temperatures (130, 160, 190, 220, 250 and 280℃), holding time (1, 2 and 3 hr), thicknesses (30, 50 and 70 mm) and heating rates (10, 20 and 30℃/hr) were examined for the best performances of heat-treated woods. The characteristics of heat-treated woods such as mass loss, moisture content, density, color change, roughness, dimensional stability, surface hardness, static bending strength, elemental analysis, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR) analysis were also assessed. Furthermore, the fundamental properties and organic compounds of wood vinegars with different heat-treated temperatures were also investigated. In addition, the normal shear strength of heated C. japonica and A. confusa woods with UF and PVAc adhesives, the performances of finishing properties of woods with PU and NC coatings, and the decay-resistance of woods by soil block test were also conducted. The results indicated that the best heat-treated conditions for the superior of dimensional stability, hardness and static bending strength of woods included heating rates of 10℃/hr, temperature of 190℃, wood thickness of 50 mm, and holding time of 2 hr for C. japonica and 3 hr for A. confusa were obtained. Moreover, under the conditions using in this experiment, the suitable thickness of heat treatment were 25 mm for C. japonica and 20 mm for A. confusa by color and FT-IR analyses. The yield, gardner color and specific gravitie of wood vinegars obtained from C. japonica and A. confusa decreased with increasing heat-treated temperatures, and the specific gravities of 0.983-1.030, pH of 2.55-3.43 and organic acid contents of 0.06-9.11% of wood vinegars will also obtained. The kinds of organic acids increased with increasing the heated temperature by GC-MS analysis. For C. japonica wood vinegar, the main compound was isoledene for 130, 160 and 190℃ heat treatment; the acetic acid was the main one of acidic components for 220℃ heat treatment, and 2-methoxy-phenol and 2-methoxy-4-methyl-phenol were the major compounds of phenol components for 280℃ treatment. For A. confusa wood vinegar, the fatty acids were the main one for 130℃ treatment, while the acetic acid was the major one of acidic components for heat-treated temperatures; the andrographolide and 3-furaldehyde were the main compounds of neutral components for 160℃ and over 190℃ treatments, respectively; the 2,6-dimethoxy-phenol and mequinol were the major compounds of phenol components for over 220℃ treatments and it also increased with increasing heated temperature. The normal shear strength of heat-treated C. japonica and A. confusa woods with UF and PVAc adhesives was low than that of untreated wood. Furthermore, the adhesion and impact resistance of heat-treated C. japonica and A. confusa woods finishing with PU and NC coatings showed no significant differences with untreated woods, the finished heat-treated wood also showed superior durability and had better gloss retention and lightfastness than those of untreated wood. The heat-treated woods also had a better decay-resistance than untreated wood by soil block test.摘要………………………………………………………………………i Summary…………………………………………………………………iii 目次………………………………………………………………………v 表目次…………………………………………………………………vii 圖目次…………………………………………………………………xv 第一章 前言……………………………………………………………1 第二章 文獻回顧………………………………………………………3 一、全球木質材料發展趨勢…………………………………………3 二、木材改質之發展…………………………………………………4 三、熱處理材之背景與機制…………………………………………5 四、木材熱解機制與木醋液…………………………………………11 五、熱處理材之應用…………………………………………………14 第三章 柳杉與相思樹材之熱處理……………………………………17 一、實驗材料…………………………………………………………17 二、實驗方法…………………………………………………………17 （一）木材組成分分析……………………………………………17 （二）木材熱處理…………………………………………………20 （三）熱處理材性質之分析………………………………………22 三、結果與討論………………………………………………………28 （一）不同溫度熱處理柳杉與相思樹……………………………28 （二）不同持溫時間熱處理柳杉與相思樹材……………………55 （三）不同厚度柳杉與相思熱處理材……………………………71 （四）不同升溫速率熱處理柳杉與相思熱處理材………………90 第四章 不同溫度熱處理柳杉與相思樹材木醋液之基本性質及有機成分………………………………………………………………………104 一、實驗材料………………………………………………………104 二、實驗方法………………………………………………………104 三、結果與討論……………………………………………………106 第五章 熱處理材膠合、塗裝與耐腐朽性…………………………120 一、實驗材料………………………………………………………120 二、實驗方法………………………………………………………121 三、結果與討論……………………………………………………125 （一）熱處理材之膠合強度……………………………………125 （二）熱處理材之塗裝性能……………………………………127 （三）熱處理材之耐腐朽性……………………………………133 第六章結論……………………………………………………………136 參考文獻………………………………………………………………13

不同溫度熱處理柳杉與相思樹木材之特性

In this study, a non-toxic heat-treated technology was applied for improving the dimensional stability of wood. A 20-30 years old Cryptomeria japonica and Acacia confusa wood with thickness of 5 cm and moisture content of 12% were used. The heat treatment was conducted using an activated furnace under N2 atmosphere and the samples were subjected to heat treatment at 130, 160, 190, 220, 250, and 280℃, respectively at a heating rate of 20℃/hr and holding time of 2 hr. The characteristics of heat-treated wood such as mass loss, moisture content, density, shrinkage ratio, color change, roughness, dimensional stability contact angle, surface hardness, static bending strength as well as Fourier transform infrared spectroscopy (FT-IR) analysis were examined. The results showed that the mass loss and color difference (△E*) of heated-treated wood increased with increasing heated temperatures, while the moisture content and density had the reverse results. Furthermore, after heated treatment the smoother surface of wood was obtained. The anti-swelling efficiency (ASE) and moisture excluding efficiency (MEE) could be improved significantly at higher heat-treated temperatures. The surface hardness of below 220℃ heat-treated C. japonica wood was higher than that of un-treated wood. The surface hardness of below 190℃ heat-treated A. confusa wood was higher than that of un-treated wood, while the hardness decreased significantly for the one over 190℃ treatment. The modulus of rupture (MOR) of wood with over 190℃ treatment decreased with increasing heated temperatures. However, C. japonica and A. confusa with 160 and 190℃ treatment had the highest modulus of elasticity (MOE). According to FT-IR, the contents of hemicellulose and cellulose of treated wood were lower than those of untreated wood, and which decreased with increasing heated temperatures. But the relative content of lignin increased with increasing heated temperatures.本研究係以無毒之熱處理技術，擬改善木材尺寸安定性。材料為20-30年生，厚度5 cm之柳杉（Cryptomeria japonica）與相思樹（Acacia confusa），含水率12%；利用炭化爐，通入N2，在升溫速率20℃/ hr下，分別加熱至130、160、190、220、250及280℃，並持溫2 hr進行熱處理，探討不同溫度熱處理材之質量損失、密度、平衡含水率、尺寸減低率、色差值、粗糙度、尺寸安定性、接觸角、硬度、抗彎強度及傅立葉紅外線光譜（FT-IR）分析。試驗結果顯示，柳杉與相思樹木材經不同溫度熱處理後，質量損失隨處理溫度提高而增加，而密度與平衡含水率明顯降低；色差值（△E*）隨熱處理溫度之提升而增加，表面粗糙度經熱處理後則較為平滑；抗膨脹效能（Anti-swelling effi ciency,ASE）與抗吸濕效能（Moisture excluding efficiency, MEE）隨熱處理溫度提高有明顯之改善效果。柳杉與相思樹材經熱處理後，木材表面具較佳疏水性，且會隨熱處理溫度升高而增加。在熱處理材之表面硬度方面，柳杉木材以220℃以下處理之硬度值較未處理材高，且會隨溫度升高而增加，而相思樹木材以190℃以下處理之硬度值較未處理材為高，但以190℃以上熱處理硬度則明顯降低。兩種木材之抗彎強度（Modulus of rupture, MOR）均隨隨熱處理溫度增加而降低，但柳杉與相思樹之抗彎彈性模數 （Modulus of elasticity, MOE）分別以溫度160與190℃熱處理者最佳。在傅立葉紅外線光譜（Fourier transform infrared spectroscopy, FT-IR）分析顯示，經熱處理後木材半纖維素及纖維素含量明顯減少，且隨處理溫度增加而降低更多，但木質素相對含量則隨處理溫度增加而提高