Bioresource Processing Research Institute of Australia (BioPRIA), Department of Chemical and Biological Engineering, Monash University, VIC 3800, Australia.
Department of Chemical Engineering, Muhammad Nawaz Sharif University of Engineering and Technology, BCG Chowk, Multan, Pakistan.
Sci Total Environ. 2022 Aug 25;836:155654. doi: 10.1016/j.scitotenv.2022.155654. Epub 2022 May 1.
Plastic packaging is causing a serious environmental concern owing to its difficulty in degrading and micro-particulates' emissions. Developing biodegradable films has gained research attention to overcome ecological and health issues associated with plastic based packaging. One alternative substitute for petroleum-based plastic is nanocellulose based films, having distinguishing characteristics such as biodegradability, renewability, and non-toxicity. Nanocellulose is classified into three major types, i.e., cellulose nanofibril, cellulose nanocrystals, and bacterial nanocellulose. However, the scope of this review is limited to cellulose nanofibril (CNF) because this is the only one of major types that could be turned into film at a competitive cost with petroleum derived polymers. This paper provides a concise insight on the current trends and production methods of CNF. Additionally, the methods for transforming CNF into films are also discussed in this review. However, the focus of this review is the CNF films produced via spray deposition, their properties and applications, and fundamental challenges associated with their commercialization. Spray deposition or spray coating is an ideal candidate as a large-scale production technique of CNF films due to its remarkable features such as rapidity, flexibility, and continuity. Spray deposited CNF films exhibit excellent mechanical properties and oxygen barrier performance, while, possessing limited moisture barrier performance. The possible pathways to improve the moisture barrier performance and optical properties of these films are also discussed in this review. The existing publications on spray deposited CNF films are also highlighted from the literature. Finally, the current status of industrial production of these films and opportunities for academics and industries are also presented, indicating that fibre production capacity needs to be enhanced.
由于其难以降解和微颗粒排放，塑料包装对环境造成了严重的关注。开发可生物降解薄膜引起了研究关注，以克服与塑料包装相关的生态和健康问题。替代石油基塑料的一种选择是基于纳米纤维素的薄膜，具有生物降解性、可再生性和非毒性等特点。纳米纤维素分为三种主要类型，即纤维素纳米纤维、纤维素纳米晶体和细菌纳米纤维素。然而，本综述的范围仅限于纤维素纳米纤维（CNF），因为这是唯一一种可以以具有竞争力的成本转化为薄膜的主要类型，可以与石油衍生聚合物相媲美。本文简要介绍了 CNF 的当前趋势和生产方法。此外，还讨论了将 CNF 转化为薄膜的方法。然而，本综述的重点是通过喷雾沉积生产的 CNF 薄膜、它们的性质和应用，以及与它们商业化相关的基本挑战。喷雾沉积或喷雾涂层是 CNF 薄膜大规模生产技术的理想选择，因为它具有快速、灵活和连续等显著特点。喷雾沉积的 CNF 薄膜具有优异的机械性能和氧气阻隔性能，同时具有有限的防潮性能。本文还讨论了提高这些薄膜防潮性能和光学性能的可能途径。还从文献中突出了关于喷雾沉积 CNF 薄膜的现有出版物。最后，还介绍了这些薄膜的工业生产现状以及学术界和工业界的机会，表明需要提高纤维生产能力。
