Comparative properties of cellulose nano-crystals from native and mercerized cotton fibers
Comparative properties of cellulose nano-crystals from native and mercerized cotton fibers
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原棉纤维和丝光棉纤维纳米纤维素晶体的性能比较
DOI：
10.1007/s10570-012-9714-4
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发表时间：
2012-08-01
期刊：
影响因子：
5.7
通讯作者：
Wu, Qinglin
中科院分区：
文献类型：
--
作者：
Yue, Yiying;Zhou, Chengjun;Wu, Qinglin
采用硫酸水解法和高压均质法制备了稳定的纤维素纳米晶体（CNCs）水悬浮液。傅里叶变换红外光谱和广角X射线衍射数据表明，纤维已从纤维素I（天然）转化为纤维素II（丝光）的晶体结构，这些多晶型物保留在纳米晶体中，得到CNC-I和CNC-II。透射电子显微镜显示棒状晶体形态的两种类型的晶体在给定的加工条件下与CNC-II具有相似的宽度，但长度减少。CNC-II的冷冻干燥团聚体具有比CNC-I高得多的堆积密度。热重分析表明，CNC-II具有较好的热稳定性。在所有温度下的CNC-II悬浮液的储能模量基本上大于在相同浓度水平的CNC-I悬浮液。CNC-II悬浮液和凝胶对温度升高的反应更稳定。测试CNC和聚（环氧乙烷）的膜。与纯PEO相比，CNC-I/PEO和CNC-II/PEO复合材料的拉伸强度和断裂伸长率均有所增加。然而，与CNC-II的复合材料具有更高的强度和伸长率比与CNC-I的复合材料。
Stable aqueous suspensions of cellulose nano-crystals (CNCs) were fabricated from both native and mercerized cotton fibers by sulfuric acid hydrolysis, followed by high-pressure homogenization. Fourier transform infrared spectrometry and wide-angle X-ray diffraction data showed that the fibers had been transformed from cellulose I (native) to cellulose II (mercerized) crystal structure, and these polymorphs were retained in the nanocrystals, giving CNC-I and CNC-II. Transmission electron microscopy showed rod-like crystal morphology for both types of crystals under the given processing conditions with CNC-II having similar width but reduced length. Freeze-dried agglomerates of CNC-II had a much higher bulk density than that of CNC-I. Thermo-gravimetric analysis showed that CNC-II had better thermal stability. The storage moduli of CNC-II suspensions at all temperatures were substantially larger than those of CNC-I suspensions at the same concentration level. CNC-II suspensions and gels were more stable in response to temperature increases. Films of CNC and Poly(ethylene oxide) were tested. Both CNC-I/PEO and CNC-II/PEO composites showed increased tensile strength and elongation at break compared to pure PEO. However, composites with CNC-II had higher strength and elongation than composites with CNC-I.