Enzymatically hydrolyzed and TEMPO-oxidized cellulose nanofibers for the production of nanopapers: morphological, optical, thermal and mechanical properties

Abstract

In the present study, CNF prepared by TEMPO-mediated oxidation and enzymatic hydrolysis were used for the production of nanopapers using a papermaking-like route. Nanopapers were characterized in terms of tensile, thermal, optical and morphological properties. Those prepared from enzymatically hydrolyzed CNF were found to be weaker at tensile than those resulting from TEMPO-mediated oxidation, but with similar level of stiffness. Enzymatically obtained CNF presented lower transparency due to their higher diameter and lower fibrillation yield. Moreover, TEMPO-oxidized CNF presented lower onset of the thermal degradation temperature (230 °C) due to the presence of carboxylic groups. Overall, the influence of increasing the amount of enzyme during enzymatic hydrolysis and the amount of sodium hypochlorite during TEMPO-mediated oxidation was assessed as function of the ultimate properties of nanopapers.