Nanocomposites prepared by in situ enzymatic polymerization of phenol with TEMPO-oxidized nanocellulose

The objective of this study was to prepare nanocomposites based on polyphenols and nanocellulose fibers using relatively benign processing. To accomplish this, phenol was polymerized using horseradish peroxidase in the presence of TEMPO-oxidized nanocellulose. The polyphenol-nanocellulose composite was insoluble in organic solvents but the individual components were soluble. SEM imaging of fracture surfaces of polyphenol, nanocellulose, and composite indicated brittle failure in polyphenol and nanocellulose but ductile failure in the composite pointing to a potential synergistic effect from the addition of the components. Polyphenol existed as spherical or near-spherical clusters that were ca. 10 mu m in the absence of nanocellulose and ca. 0.1 mu m in the presence of nanocellulose. The observed change in structure corresponded to changes in the thermal stability because the composite was more thermally stable than the components. FT-IR analysis of polyphenol-nanocellulose composites showed physical and chemical interactions between the fiber and matrix. This study is a significant improvement in forming nanocomposites without the intensive processing usually required for dispersion.