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首页> 外文期刊>ACS Sustainable Chemistry & Engineering >Green One-Pot Synthesis of Surface Hydrophobized Cellulose Nanocrystals in Aqueous Medium
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Green One-Pot Synthesis of Surface Hydrophobized Cellulose Nanocrystals in Aqueous Medium

机译：水性介质中绿色一锅法合成表面疏水化纤维素纳米晶体

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The surface hydrophobization of cellulose nanocrystals (CNCs) by fatty acids (FAs), biodiesel, or plant oils was conducted via a green process using an organic solvent less one-pot method. In the process, an aqueous lactic acid syrup served as a reactive solvent to provide a stable and welldispersed water suspension of CNC and participate in esterification reactions, producing an intermediate product of polylactic acid (PLA) oligomer grafted CNCs (CNC-g-PLA). This reactive solvent and intermediate product system allows for an in situ solvent exchange from water to lactic acid without prior drying of the CNC and a subsequent efficient esterification reaction of CNC with carboxylic acids or esters having a long hydrocarbon chain (FAs). Another advantage of the proposed process is the possibility to reuse the reagents in the subsequent reaction in order to reduce the production cost. The grafting efficiency of the CNC-g-PLA-FA samples covalently grafted with PLA and FAs were characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), and 13C nuclear magnetic resonance spectroscopy (ss-NMR). The change of dimensions and degree of crystallinity of the modified CNC was evaluated by dynamic light scattering (DLS) and X-ray diffraction (XRD). Different organic solvents were used here to investigate the relative hydrophobicity of the modified CNCs comparing the transmittance of their suspensions in the ultraviolet and visible (UV-vis) spectrometer, and evaluating their hydrodynamic radius by dynamic light scattering (DLS) techniques. Grafting of renewable materials on the surface of CNCs was developed by polyesterification that is capable of being environmentally friendly and mass-produced without any organic solvents or toxic reagents.
机译：脂肪酸（FAs），生物柴油或植物油对纤维素纳米晶体（CNCs）的表面疏水化反应是通过绿色工艺使用有机溶剂少一锅法进行的。在此过程中，乳酸糖浆水溶液用作反应性溶剂，以提供稳定且分散良好的CNC水悬浮液并参与酯化反应，从而生产出聚乳酸（PLA）低聚物接枝的CNC（CNC-g-PLA）中间产物。该反应性溶剂和中间产物系统允许从水到乳酸的原位交换，而无需先进行CNC干燥，随后CNC与具有长烃链（FAs）的羧酸或酯进行有效的酯化反应。所提出的方法的另一个优点是可以在随后的反应中重复使用试剂以降低生产成本。共聚接枝PLA和FAs的CNC-g-PLA-FA样品的接枝效率通过傅里叶变换红外光谱（FT-IR），元素分析（EA）和13C核磁共振光谱（ss-NMR）进行表征。通过动态光散射（DLS）和X射线衍射（XRD）评估了改性CNC的尺寸和结晶度的变化。在这里，使用了不同的有机溶剂来研究改性CNC的相对疏水性，比较它们在紫外和可见（UV-vis）光谱仪中的悬浮液的透射率，并通过动态光散射（DLS）技术评估其流体动力学半径。 CNCs表面上的可再生材料接枝是通过聚酯化技术开发的，这种聚酯技术可以环保且可大量生产，而无需使用任何有机溶剂或有毒试剂。

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