Midhun Dominic C D, Raj Vandita, Neenu K V, Begum P M Sabura, Formela Krzysztof, Saeb Mohammad Reza, Prabhu Deepak D, Poornima Vijayan P, Ajithkumar T G, Parameswaranpillai Jyotishkumar
Department of Chemistry, Sacred Heart College (Autonomous), Kochi, Pin-682013, Kerala, India.
Department of Chemistry, Sacred Heart College (Autonomous), Kochi, Pin-682013, Kerala, India; Department of Chemistry, PSGR Krishnammal College for Women, Peelamedu, Coimbatore Pin-641004, Tamil Nadu, India.
Int J Biol Macromol. 2022 May 1;206:92-104. doi: 10.1016/j.ijbiomac.2022.02.078. Epub 2022 Feb 22.
This study aims to extract cellulose nanofibers (CNFs) from a sustainable source, i.e. millet husk, which is an agro-waste worthy of consideration. Pre-treatments such as mercerisation, steam explosion, and peroxide bleaching (chlorine-free) were applied for the removal of non-cellulosic components. The bleached millet husk pulp was subjected to acid hydrolysis (5% oxalic acid) followed by homogenization to extract CNFs. The extracted CNFs were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Dynamic Light Scattering (DLS), Energy Dispersive X-ray Spectroscopy (EDX), Thermogravimetry (TG and DTG), Differential scanning calorimetry (DSC), and Solid state C nuclear magnetic resonance spectroscopy (solid state C NMR). The isolated CNFs show a typical cellulose type-I structure with a diameter of 10-12 nm and a crystallinity index of 58.5%. The appearance of the specific peak at 89.31 ppm in the solid state C NMR spectra validates the existence of the type-I cellulose phase in the prepared CNFs. The prepared CNFs had a maximum degradation temperature (T) of 341 °C, that was 31 °C greater than raw millet husk (RMH). The outcome of the study implies that the nanofibers are prominent alternatives for synthetic fibers for assorted potential applications, especially in manufacturing green composites.
本研究旨在从可持续来源即谷壳中提取纤维素纳米纤维（CNFs），谷壳是一种值得关注的农业废弃物。采用诸如丝光处理、蒸汽爆破和过氧化物漂白（无氯）等预处理方法来去除非纤维素成分。对漂白后的谷壳浆进行酸水解（5%草酸），然后进行均质化处理以提取CNFs。使用傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、动态光散射（DLS）、能量色散X射线光谱（EDX）、热重分析（TG和DTG）、差示扫描量热法（DSC）以及固态碳核磁共振光谱（固态C NMR）对提取的CNFs进行表征。分离出的CNFs呈现典型的I型纤维素结构，直径为10 - 12纳米，结晶度指数为58.5%。固态C NMR光谱中89.31 ppm处特定峰的出现证实了制备的CNFs中存在I型纤维素相。制备的CNFs的最大降解温度（T）为341℃，比生谷壳（RMH）高31℃。该研究结果表明，这些纳米纤维是合成纤维在各种潜在应用中的突出替代品，尤其是在制造绿色复合材料方面。
