Structure-Property Relationships in Hybrid Cellulose Nanofibrils/Nafion-Based Ionic Polymer-Metal Composites

• Published in: Materials Vol. 12; no. 8; p. 1269
• Main Authors: Noonan, Colin, Tajvidi, Mehdi, Tayeb, Ali H, Shahinpoor, Mohsen, Tabatabaie, Seyed Ehsan
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18.04.2019; MDPI
• Subjects: Biodegradability; Biopolymers; Cellulose; cellulose nanofibrils; Chemical reduction; Copolymers; Crosslinking; Electrodes; Formulations; Fuel cells; ionic polymer-metal composites; Mechanical properties; Membranes; Modulus of elasticity; Morphology; Nafion®, physical and mechanical properties; Nanomaterials; Oxidation; Plating; Polymer matrix composites; Polymers; Production costs; Reagents; Redox reactions; Scanning electron microscopy; Stability analysis; Thermal stability; Thermodynamic properties; Thermogravimetric analysis; United States > US; Japan; cellulose nanofibrils; Nafion®, physical and mechanical properties; ionic polymer-metal composites
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma12081269

Herein, we report the production of ionic polymer-metal composites (IPMCs) hybridized with cellulose nanofibrils (CNF) as a partial substitute for Nafion . The aim is not only to reduce the production cost and enhance respective mechanical/thermal properties but also to bestow a considerable degree of biodegradability to such products. Formulations with different CNF/Nafion ratios were produced in a thin-film casting process. Crack-free films were air-dried and plated by platinum (Pt) through an oxidation-reduction reaction. The produced hybrids were analyzed in terms of thermal stability, mechanical and morphological aspects to examine their performance compared to the Nafion-based IPMC prior to plating process. Results indicated that films with higher CNF loadings had improved tensile strengths and elastic moduli but reduced ductility. Thermogravimetric analysis (TGA) showed that the incorporation of CNF to the matrix reduced its thermal stability almost linearly, however, the onset of decomposition point remained above 120 °C, which was far above the temperature the composite membrane is expected to be exposed to. The addition of a cross-linking agent to the formulations helped with maintaining the integrity of the membranes during the plating process, thereby improving surface conductivity. The focus of the current study was on the physical and morphological properties of the films, and the presented data advocate the potential utilization of CNF as a nontoxic and sustainable bio-polymer for blending with perfluorosulfonic acid-based co-polymers, such as Nafion , to be used in electroactive membranes.