Preparation and characterization of nanopaper from regenerated cellulose

Abstract

Cellulose nanopapers (RCNP) were prepared from regenerated cellulose (RC) via the solvent casting method. RC was prepared by dissolution of bleached eucalyptus cellulose pulp (BEP) with 85% H3PO4 at -20oC. Water was applied as anti-solvent in the regenerated process. Effects of storage time after dissolution on fiber solubility were investigated at 0, 20, 40, 60 min, 1, and 2 days. ATR FT-IR spectra and crystalline index proved that regenerated cellulose was obtained. The crystalline index of the fiber became stable at 60 min, indicating the fibers were completely dissolved at 60 min. The results from thermogravimetric analysis showed that after the main degradation process, the remained char residue at 600 °C was close to 13.6% or 24.9% for original BEP or RCNP-0 min, respectively. The formation of phosphate groups on fiber surface caused increasing in remained char residue, indicating the RCNP had flame resistance property. Mechanical properties of RCNP were constant at 60 min of storage time, corresponding to the complete dissolution of fiber. Lastly, RCNP-60 min was embedded with zinc oxide nanoparticles. The UV-vis transmittance spectra of ZnO/cellulose nanopaper were investigated under a wavelength range of 300-400 nm. It was found that the 3 %wt. ZnO/cellulose nanopaper had a UV transmission value equal to 0.46%, indicating the potential usage of the cellulose nanopaper filled ZnO nanoparticles for UV-blocking films.