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Preparation of cellulose nanospheres via combining ZnCl2·3H2O pretreatment and p-toluenesulfonic hydrolysis as a two-step method
International Journal of Biological Macromolecules ( IF 7.7 ) Pub Date : 2021-03-30 , DOI: 10.1016/j.ijbiomac.2021.03.168
Qi Liu 1 , Ning Chen 1 , Xiangyun Yin 1 , Lixia Long 1 , Xin Hou 1 , Jin Zhao 1 , Xubo Yuan 1
Affiliation  

Spherical nanocelluloses, also known as cellulose nanospheres (CNS), have controllable morphology and have shown advantages as green template material, emulsion stabilizer. Herein, CNS were prepared via a new two-step method, first pretreatment of microcrystalline cellulose (MCC) using ZnCl2·3H2O and then acid hydrolysis of regenerated cellulose (RC) via p-toluenesulfonic acid (p-TsOH). The shape, size, crystallinity of MCC were changed, and nubbly RC with smallest size (942 nm) was obtained after 2 h pretreatment by ZnCl2·3H2O. CNS with high 61.3% yield were produced after acid hydrolysis (67 wt% p-TsOH) of RC at 80 °C, 6 h. The analysis of Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) showed that CNS had an average diameter of 347 nm. CNS were present in precipitate after high-speed centrifugation, due to the high Zeta potential of −12 mV and large size. The structure of CNS was tested by Fourier Transfer Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Nuclear Magnetic Resonance (NMR), CNS had high crystallinity (cellulose II) of 61%. Thermal Gravimetric Analysis (TGA) indicated that CNS had high thermal stability (Tonset 303.3 °C, Tmax 332 °C). CNS showed poor re-dispersibility in water/ethanol/THF, 1 wt% CNS could be dissolved in ZnCl2·3H2O. 7.37% rod-like CNC were obtained after 6 h hydrolysis. FTIR proved that p-TsOH was recovered by re-crystallization. This study provided a novel, sustainable two-step method for the preparation of spherical CNS.



中文翻译:

ZnCl 2 ·3H 2 O预处理与对甲苯磺酸水解两步法联合制备纤维素纳米球

球形纳米纤维素,也称为纤维素纳米球(CNS),具有可控的形态,并显示出作为绿色模板材料,乳液稳定剂的优势。本文中,CNS通过新的两步法制备,首先使用ZnCl 2 ·3H 2 O预处理微晶纤维素(MCC),然后通过对甲苯磺酸(p-TsOH)对再生纤维素(RC)进行酸水解。改变了MCC的形状,大小和结晶度,并在ZnCl 2 ·3H 2预处理2 h后获得了最小尺寸(942 nm)的块状RC。O. RC在80°C,6 h酸水解(67 wt%p-TsOH)后,生成具有61.3%高收率的CNS。动态光散射(DLS),透射电子显微镜(TEM)的分析表明,CNS的平均直径为347 nm。由于-12 mV的高Zeta电位和大尺寸,高速离心后沉淀物中存在CNS。CNS的结构通过傅立叶转移红外光谱(FTIR),X射线衍射(XRD),核磁共振(NMR)进行了测试,CNS具有61%的高结晶度(纤维素II)。热重分析(TGA)表明,CNS具有很高的热稳定性(起始温度为303.3°C,最高温度为332°C)。CNS在水/乙醇/ THF中的再分散性较差,可将1 wt%CNS溶于ZnCl 2 ·3H水解6小时后,获得2 O. 7.37%的棒状CNC。FTIR证明通过重结晶回收了对-TsOH。这项研究提供了一种新颖,可持续的两步法制备球形CNS。

更新日期:2021-04-06
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