Joram Mendoza David, Mouterde Louis M M, Browne Christine, Singh Raghuwanshi Vikram, Simon George P, Garnier Gil, Allais Florent
Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia.
URD Agro-Biotechnologies Industrielles (ABI), CEBB, AgroParisTech, 51110, Pomacle, France.
ChemSusChem. 2020 Dec 17;13(24):6552-6561. doi: 10.1002/cssc.202002017. Epub 2020 Oct 5.
New nature-inspired and plant-derived p-hydroxycinnamate esters and p-hydroxycinnamate diesters provide excellent protection against UV radiation when incorporated into a matrix. Herein, an efficient and sustainable pathway is reported to graft these phenolic compounds onto cellulose nanocrystals (CNCs) via click-type copper-catalyzed azide/alkyne cycloaddition (CuAAC) reaction. The successful grafting of the phenolic esters on CNC surface was evidenced by a range of chemical analyses, and the degrees of substitution (DS) of the CNC were found to depend on the structure of the phenolic ester grafted. Moreover, aqueous suspensions of the phenolic ester-grafted CNCs not only strongly absorb in both the UVA and UVB regions, but they also exhibit average to very high photostability. Their wide spectrum UV-absorbing properties and their stability upon exposure to UV are highly influenced by the structure of the phenolic ester, particularly by the extra ester group in p-hydroxycinnamate diesters. These findings demonstrate that cellulose nanocrystals decorated with such plant-derived and nature-inspired phenolic esters are promising sustainable nanomaterials for anti-UV applications.
新型受自然启发和源自植物的对羟基肉桂酸酯及对羟基肉桂酸二酯在掺入基质时能提供出色的抗紫外线辐射保护。在此，报道了一种高效且可持续的途径，通过点击型铜催化叠氮化物/炔烃环加成（CuAAC）反应将这些酚类化合物接枝到纤维素纳米晶体（CNC）上。通过一系列化学分析证明了酚酯在CNC表面的成功接枝，并且发现CNC的取代度（DS）取决于接枝的酚酯结构。此外，酚酯接枝的CNC的水悬浮液不仅在UVA和UVB区域都有强烈吸收，而且还表现出中等至非常高的光稳定性。它们的广谱紫外线吸收特性以及暴露于紫外线时的稳定性受到酚酯结构的高度影响，特别是对羟基肉桂酸二酯中的额外酯基。这些发现表明，用此类源自植物和受自然启发的酚酯修饰的纤维素纳米晶体是用于抗紫外线应用的有前景的可持续纳米材料。
