Research Center of Nano Science and Technology, Shanghai University, Shanghai 200444, PR China.
Research Center of Nano Science and Technology, Shanghai University, Shanghai 200444, PR China.
Carbohydr Polym. 2017 Apr 1;161:253-260. doi: 10.1016/j.carbpol.2017.01.030. Epub 2017 Jan 9.
High-efficient transparent UV-blocking nanocellulose (NC) films were successfully assembled by pressured-extrusion of the composites of carbon dots (CDs), 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radical mediated oxidized nanocellulose (ONC) and ZnO nanostructures. ONC nanofibrils were firstly extracted from bamboo fibers and subsequently prepared by applying TEMPO oxidation. The as-obtained CDs-ONC-ZnO films exhibited high visible light transparency, excellent thermal stability and enhanced UV-blocking properties. Compared to the previously designed NC-ZnO films, CDs-ONC-ZnO films presented significant increase of UV-blocking ratio (UVR) with the same amounts of ZnO. Moreover, the UVR of CDs-ONC-s-ZnO film with 4wt% sheet-like ZnO (s-ZnO) at 300nm and 225nm is 92.74% and 98.99%, better than the same condition of CDs-ONC-b-ZnO film added with belt-like ZnO (b-ZnO) and CDs-ONC-p-ZnO film added with commercial particulate ZnO (p-ZnO). An interesting discovery is that when adding 4wt% p-ZnO, the UVR of CDs-ONC-p-ZnO film is very close to the value of NC-s-ZnO film with the same amount of s-ZnO.
高效透明的紫外阻隔纳米纤维素（NC）薄膜通过将碳点（CDs）、2,2,6,6-四甲基-1-哌啶氧基（TEMPO）自由基介导氧化纳米纤维素（ONC）和 ZnO 纳米结构的复合材料进行加压挤出而成功组装。首先从竹纤维中提取 ONC 纳米原纤维，然后通过 TEMPO 氧化进行制备。所得到的 CDs-ONC-ZnO 薄膜表现出高可见光透明度、优异的热稳定性和增强的紫外阻隔性能。与之前设计的 NC-ZnO 薄膜相比，CDs-ONC-ZnO 薄膜在相同量的 ZnO 下表现出显著提高的紫外阻隔率（UVR）。此外，在 300nm 和 225nm 处，添加 4wt%片状 ZnO（s-ZnO）的 CDs-ONC-s-ZnO 薄膜的 UVR 为 92.74%和 98.99%，优于添加带状 ZnO（b-ZnO）的相同条件下的 CDs-ONC-b-ZnO 薄膜和添加商业颗粒状 ZnO（p-ZnO）的 CDs-ONC-p-ZnO 薄膜。一个有趣的发现是，当添加 4wt%的 p-ZnO 时，CDs-ONC-p-ZnO 薄膜的 UVR 非常接近添加相同量 s-ZnO 的 NC-s-ZnO 薄膜的值。
