Cainglet Hans Estrella, Black Jay R, Udugoda Hashini, Nasiri Naghmeh, Diaz-Arenas Gloria Lizeth, Garnier Gil, Batchelor Warren, Tanner Joanne
Bioresource Processing Research Institute of Australia, Department of Chemical and Biological Engineering, Monash University, Clayton, VIC 3800, Australia.
School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Victoria 3010, Australia; Trace Analysis for Chemical, Earth and Environmental Sciences (TrACEES) Platform, The University of Melbourne, Victoria 3010, Australia.
J Colloid Interface Sci. 2025 Jan 15;678(Pt C):547-555. doi: 10.1016/j.jcis.2024.09.060. Epub 2024 Sep 14.
Despite significant research into cellulose nanofibril (CNF) films as substitutes to synthetic plastic materials, commercial applications remain very limited. One major hindrance is the poor water vapor barrier properties of CNF films compared to polyolefins, a critical property for product protection, such as food safety and preservation. To date, it is unknown whether full moisture barrier properties can be achieved with materials made by the assembly of nanofibers and fibrils. A comprehensive understanding of the effect of film structure on water vapor transport properties is required. Here, over 200 films were produced with a wide range of grammages from 30 g/m to 580 g/m by casting and spray deposition. Their structures were quantified by µCT and SEM and related to their water vapor transmission rates (WVTRs). Porosity and pore connectivity decreased with increasing film grammage, which correlates with the exponential decrease in WVTR. However, the WVTR plateaued at 30 g/mday, indicating that the known open space and adsorption diffusion mechanisms cannot be fully eliminated by producing high grammage films. Pure cellulose nanofibril films therefore cannot replace polyolefins in packaging applications, requiring modifications such as coating and nanofillers.
尽管对纤维素纳米原纤（CNF）薄膜作为合成塑料材料的替代品进行了大量研究，但其商业应用仍然非常有限。一个主要障碍是与聚烯烃相比，CNF薄膜的水汽阻隔性能较差，而这是产品保护（如食品安全和保鲜）的关键性能。迄今为止，尚不清楚由纳米纤维和原纤组装而成的材料是否能够实现完全的防潮性能。需要全面了解薄膜结构对水汽传输性能的影响。在此，通过流延和喷雾沉积制备了200多种克重范围从30 g/m²到580 g/m²的薄膜。通过µCT和SEM对其结构进行了量化，并将其与水汽透过率（WVTR）相关联。孔隙率和孔隙连通性随薄膜克重增加而降低，这与WVTR的指数下降相关。然而，WVTR在30 g/m²·天处趋于平稳，这表明通过制备高克重薄膜并不能完全消除已知的开放空间和吸附扩散机制。因此，纯纤维素纳米原纤薄膜在包装应用中无法替代聚烯烃，需要进行诸如涂层和添加纳米填料等改性处理。
