Department of Chemistry, University of Calicut, Kerala, 673635, India.
Department of Chemistry, University of Calicut, Kerala, 673635, India.
Carbohydr Polym. 2018 Jan 15;180:13-20. doi: 10.1016/j.carbpol.2017.09.088. Epub 2017 Sep 28.
Sago (Cycas circinalis) seed shells are agricultural waste materials discarded after taking the pith. In the present study Cellulose nanocrystals (CNCs) are isolated from the sago seed shells by acid hydrolysis. The hydrolysis was performed with 64% (w/w) sulphuric acid. The resulting CNCs were characterized by FTIR, XRD, SEM, TEM, AFM, DLS, Zeta (ζ) potential and TGA. FTIR spectrum of CNCs shows similar frequencies as that of α-cellulose, but with reduced intensity. XRD diffraction pattern shows co-existence of cellulose I and cellulose II with crystallinity index of 72% for cellulose II, 69% for cellulose I and crystallite size dimension of 9.4nm for cellulose I. SEM analysis clearly reveals the considerable size reduction during acid hydrolysis. TEM analysis shows that the isolated CNCs contain networked structures and almost spherical shaped particles having 10-15nm in size. Morphological examination through AFM also shows that isolated CNCs are in nano dimensions, having the size ∼50nm. DLS analysis gives an average size of 50nm and zeta (ζ) potential measured has a value of -37.8mV. DLS and AFM analyses support each other. TGA reveals lower thermal stability for CNCs.
西米（鱼尾葵）种子壳是在提取髓心后丢弃的农业废料。在本研究中，通过酸水解从西米种子壳中分离出纤维素纳米晶体（CNC）。水解使用 64%（w/w）硫酸进行。所得 CNC 通过 FTIR、XRD、SEM、TEM、AFM、DLS、Zeta（ζ）电位和 TGA 进行表征。CNC 的 FTIR 光谱显示出与α-纤维素相似的频率，但强度降低。XRD 衍射图谱显示纤维素 I 和纤维素 II 共存，纤维素 II 的结晶度指数为 72%，纤维素 I 的结晶度指数为 69%，纤维素 I 的晶粒尺寸为 9.4nm。SEM 分析清楚地表明在酸水解过程中发生了相当大的尺寸减小。TEM 分析表明，分离出的 CNC 含有网状结构和几乎球形的颗粒，尺寸为 10-15nm。通过 AFM 进行的形态检查还表明，分离出的 CNC 处于纳米尺寸，尺寸约为 50nm。DLS 分析给出了 50nm 的平均尺寸，测量的 Zeta（ζ）电位值为-37.8mV。DLS 和 AFM 分析相互支持。TGA 表明 CNC 的热稳定性较低。
