Park Jinsu, Kim Youngeun, Kwak Seung-Yeop
Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
ACS Appl Mater Interfaces. 2024 Oct 23;16(42):57915-57926. doi: 10.1021/acsami.4c13523. Epub 2024 Oct 10.
Upcoming regulations aim to ban per- and polyfluoroalkyl substances (PFAS), including commercial polymeric PFAS, or fluoropolymers, such as poly(tetrafluoroethylene) (PTFE) and poly(vinylidene fluoride) (PVDF), due to their environmental and toxicological impacts. However, fluoropolymers also provide crucial properties for clean energy transitions, and their regulation may hinder further technological advancements. Therefore, a facile one-pot recycling-upcycling strategy for fluoropolymers using inexpensive biomass, such as cellulose nanocrystals (CNCs), as absorbents and cocomponents for fluoro-functionalized composites could align with global sustainability goals and technological demands. Herein, we present a closed-loop CNC-in-solvent (CiS) processing system, which involves stirring fluoropolymers and CNCs in only low-polarity solvents like toluene (CiS-T). Our study reveals that CiS-T is a two-step process where the CNC-solvent interaction exposes CNCs' reducing end aldehyde protons due to solvent polarity and promotes H-F bond formation. The solvent used was recollected and reused. Additionally, we demonstrate the practical application of PTFE- and PVDF-CNC hybrids, byproducts of the CiS-T process, as performance-enhancing agents in green-energy-harvesting devices such as triboelectric nanogenerators. Our findings not only offer a sustainable method to overcome challenges from regulations against commercial fluoropolymers but also offer insights into developing an efficient, solvent-mediated CNC functionalization process that addresses forthcoming challenges in key industries.
即将出台的法规旨在禁止全氟和多氟烷基物质（PFAS），包括商业聚合物PFAS或含氟聚合物，如聚四氟乙烯（PTFE）和聚偏二氟乙烯（PVDF），因为它们对环境和毒理学有影响。然而，含氟聚合物也为清洁能源转型提供了关键特性，对其进行监管可能会阻碍进一步的技术进步。因此，一种使用廉价生物质（如纤维素纳米晶体（CNC））作为氟功能化复合材料的吸收剂和共组分的简便一锅法回收-升级循环策略，可能符合全球可持续发展目标和技术需求。在此，我们展示了一种闭环的溶剂中纤维素纳米晶体（CiS）加工系统，该系统包括仅在甲苯等低极性溶剂中搅拌含氟聚合物和CNC（CiS-T）。我们的研究表明，CiS-T是一个两步过程，其中CNC与溶剂的相互作用由于溶剂极性而暴露出CNC的还原端醛质子，并促进H-F键的形成。所使用的溶剂被回收并再利用。此外，我们展示了CiS-T过程的副产物PTFE-和PVDF-CNC杂化物作为绿色能源收集设备（如摩擦纳米发电机）中的性能增强剂的实际应用。我们的研究结果不仅提供了一种可持续的方法来克服针对商业含氟聚合物的法规带来的挑战，还为开发一种高效的、溶剂介导的CNC功能化过程提供了见解，该过程可应对关键行业即将面临的挑战。
