Comparative study of paper and nanopaper properties prepared from bacterial cellulose nanofibers and fibers/ground cellulose nanofibers of canola straw

Abstract: Nanopaper was prepared using ground cellulose nanofibers (GC) from canola straw and bacterial cellulose nanofibers (BC). The characteristics of GC and BC nanopapers were investigated and compared. Micropaper was also prepared from as-bleached cellulose microfibers of canola straw, used as a control sample to evaluate the effect of grinding on the properties of cellulose nanofibers and nanopaper. The average diameters for the microfiber, GC and BC were 26μm, 32nm and 45nm, respectively. Micropaper had crystallinity and crystallite size of 69% and 5.5nm, respectively. As the result of grinding, the crystallinity and crystallite size of GC nanopaper dropped to 62% and 5.1nm, respectively. BC nanopaper showed the highest values, with 80% and 6.2nm, respectively. GC nanopaper had a lower onset temperature (270°C) and thermal stability than that of both micropaper (275°C) and BC nanopaper (320°C). Micropaper was permeable to air while GC and BC nanopapers showed very high barrier property. Grinding had a drastic positive effect on mechanical properties: the tensile strength and Young''s modulus of GC nanopaper increased 11 times on average over those of micropaper, reaching 114MPa and 13.6GPa, respectively. BC nanopaper had the highest tensile strength and Young''s modulus, with 185MPa and 17.3GPa, respectively. GC and BC nanopapers are regarded as highly tough, fully bio-based, fully biodegradable and multi-performance materials. [Copyright &y& Elsevier]