Mianehrow Hanieh, Lo Re Giada, Carosio Federico, Fina Alberto, Larsson Per Tomas, Chen Pan, Berglund Lars A
Department of Fibre and Polymer Technology, Wallenberg Wood Science Center, KTH Royal Institute of Technology, Teknikringen 56, 100 44 Stockholm, Sweden.
Department of Industrial and Materials Science, Chalmers University of Technology, Rännvägen 2, 412 96 Gothenburg, Sweden.
J Mater Chem A Mater. 2020 Sep 14;8(34):17608-17620. doi: 10.1039/D0TA04406G. Epub 2020 Jul 27.
Nanocomposites from native cellulose with low 2D nanoplatelet content are of interest as sustainable materials combining functional and structural performance. Cellulose nanofibril-graphene oxide (CNF-GO) nanocomposite films are prepared by a physical mixing-drying method, with focus on low GO content, the use of very large GO platelets (2-45μm) and nanostructural characterization using synchrotron x-ray source for WAXS and SAXS. These nanocomposites can be used as transparent coatings, strong films or membranes, as gas barriers or in laminated form. CNF nanofibrils with random in-plane orientation, form a continuous non-porous matrix with GO platelets oriented in-plane. GO reinforcement mechanisms in CNF are investigated, and relationships between nanostructure and suspension rheology, mechanical properties, optical transmittance and oxygen barrier properties are investigated as a function of GO content. A much higher modulus reinforcement efficency is observed than in previous polymer-GO studies. The absolute values for modulus and ultimate strength are as high as 17 GPa and 250 MPa at a GO content as small as 0.07 vol%. The remarkable reinforcement efficiency is due to improved organization of the CNF matrix; and this GO-induced mechanism is of general interest for nanostructural tailoring of CNF-2D nanoplatelet composites.
具有低二维纳米片含量的天然纤维素基纳米复合材料作为兼具功能和结构性能的可持续材料备受关注。纤维素纳米原纤-氧化石墨烯（CNF-GO）纳米复合薄膜通过物理混合干燥法制备，重点在于低氧化石墨烯含量、使用非常大的氧化石墨烯片（2-45μm）以及使用同步加速器X射线源进行广角X射线散射（WAXS）和小角X射线散射（SAXS）的纳米结构表征。这些纳米复合材料可用作透明涂层、坚固薄膜或膜、气体阻隔材料或以层压形式使用。具有随机面内取向的CNF纳米原纤形成了一个连续的无孔基质，氧化石墨烯片在面内取向。研究了氧化石墨烯在CNF中的增强机制，并研究了纳米结构与悬浮液流变学、机械性能、光学透过率和氧气阻隔性能之间的关系，作为氧化石墨烯含量的函数。观察到的模量增强效率比以前的聚合物-氧化石墨烯研究要高得多。在氧化石墨烯含量低至0.07体积%时，模量和极限强度的绝对值分别高达17 GPa和250 MPa。这种显著的增强效率归因于CNF基质组织的改善；并且这种氧化石墨烯诱导的机制对于CNF-二维纳米片复合材料的纳米结构定制具有普遍意义。
