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Preparation and Characterization of Nanocrystalline Cellulose by Acid Hydrolysis of Cotton Linter

棉漿酸水解法製備奈米纖維素及性質分析

摘要


本研究目的為棉漿應用硫酸水解法製備奈米纖維素,藉由24因子設計探討硫酸濃度、溫度、水解時間、固液比等因子對於得率的影響。不同硫酸濃度下所製得的奈米纖維素產物利用DLS、TEM、FTIR、13CSNMR、TGA等儀器進行檢測,以探討奈米纖維素的粒徑分布、形態、官能基轉移、碳位置及熱分解等性質。研究結果顯示,硫酸濃度與固液比在高水準時,及溫度與時間在低水準時,對奈米纖維素產量有顯著影響。主效應依序為硫酸濃度>溫度>水解時間>固液比。雷射粒徑分析儀與穿透式電子顯微鏡觀測結果顯示,實驗製得的NCC尺寸分佈集中於20~200 nm之間,長寬比由1:1~1:30不等。傅立葉轉換式紅外線光譜分析指出,在1010~1080與1150~1260 cm^(-1)處吸收峰增強,顯示纖維素長鏈上新增硫酸酯類鍵結。13C固態核磁共振圖譜指出,C4位置由87.4往低磁場區移動,顯示硫酸酯類鍵結於該位置。熱重分析結果顯示,低硫酸組奈米纖維素均在149℃左右產生第一階段重量損失,第二階段熱重損失溫度低硫酸組較中高硫酸組為高,分別是337與205℃;高硫酸組僅於243℃時產生明顯的熱重損失。本研究以酸濃度60%、固液比1:20、反應溫度45℃、水解5 min所得之收率最佳,產率為54.4%。

並列摘要


The purpose of this study was to use acid hydrolysis of cotton linter to generate nanocrystal-line cellulose (NCC). Based on a 2^4 factorial design, the effects of sulfuric acid concentration, temperature, hydrolysis time, and the solid/liquid ratio on the NCC yield were examined. NCC specimens obtained from different sulfuric acid concentrations were subjected to a battery of analyses, including dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), 13C solid-state nuclear magnetic resonance (13CSNMR), and a thermal gravimetric analysis (TGA) to probe the particle size distribution, morphology, functional group shifts, position of the carbon, and thermal degradation properties of the ensuing NCC. The results indicated that the sulfuric acid concentration and solid/liquid ratio at higher levels, and temperature and reaction time at lower levels were significantly conducive to increases in NCC yields. The main effects in diminishing order were the acid concentration, temperature, hydrolysis time, and solid/liquid ratio. Results of DLS and TEM observations suggested that the NCC had a size distribution centered around 20~200 nm, with length-to-width ratios ranging 1:1~1:30. The FTIR analysis indicated that absorption peaks at 1010~1080 and 1150~1260 cm^(-1) were derived from sulfate ester bonds on the cellulosic chains. Solid state 13CNMR spectra indicated that the C4 atoms along the cellulosic chain were shifted from 87.4 ppm to a lower magnetic domain, indicating the sulfonic ester bonding position. The TGA indicated that the lower-sulfuric-acid NCC specimen began step 1 weight loss at ca. 149℃, whereas its starting temperature of step 2 weight loss was generally higher than the mid- and high-acid NCC, at 337 and 205℃, respectively. The high-acid NCC only showed marked weight loss at 243℃. The study found that a sulfuric acid concentration of 60%, a solid/liquid ratio of 1:20, a hydrolysis temperature of 45℃, and a hydrolysis time of 5 min produced the best yield of 54.4%.

被引用紀錄


Yang, T. J. (2015). 再生纖維素薄膜之纖維方向性與其性質探討 [master's thesis, National Taiwan University]. Airiti Library. https://doi.org/10.6342%2fNTU201800036

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