Cellulose Nanocrystal-in-Solvent Processing for Efficient One-Pot Upcycling of Commercial Polymeric PFAS

Area of Science:

• Materials Science
• Green Chemistry
• Nanotechnology

Background:

• Upcoming regulations target per- and polyfluoroalkyl substances (PFAS), including essential fluoropolymers like PTFE and PVDF, due to environmental and toxicological concerns.
• Fluoropolymers are critical for clean energy technologies, and their regulation poses a significant challenge to technological advancement.
• A sustainable solution is needed to reconcile environmental regulations with the demand for fluoropolymers in emerging industries.

Purpose of the Study:

• To develop a facile one-pot recycling-upcycling strategy for fluoropolymers using cellulose nanocrystals (CNCs).
• To create fluoro-functionalized composites from recycled fluoropolymers and CNCs for sustainable applications.
• To demonstrate the utility of these novel composites in green-energy-harvesting devices.

Main Methods:

• A closed-loop CNC-in-solvent (CiS) processing system was employed, utilizing low-polarity solvents like toluene (CiS-T).
• The system involved stirring fluoropolymers (PTFE, PVDF) with CNCs to facilitate H-F bond formation and create hybrid materials.
• Solvent recovery and reuse were integrated into the process to enhance sustainability.

Main Results:

• The CiS-T process was identified as a two-step mechanism involving CNC-solvent interactions and H-F bond formation.
• Recycled PTFE- and PVDF-CNC hybrids were successfully produced as byproducts.
• These hybrid materials demonstrated practical application as performance-enhancing agents in triboelectric nanogenerators.

Conclusions:

• The developed CNC-in-solvent (CiS) system offers a sustainable pathway for fluoropolymer recycling and upcycling.
• This approach aligns with global sustainability goals by addressing regulatory challenges and supporting clean energy transitions.
• The findings provide insights into efficient, solvent-mediated CNC functionalization for future industrial applications.