Preparation and characterization of transparent cellulose films using an improved cellulose dissolution process

Effective dissolution of cellulosic macromolecules is the first predominant step to prepare functional bio‐based materials with desirable properties. In this study, we developed an improved dissolution process using a freeze‐drying pretreatment to promote the dissolution of cellulose. Rheological measurements of cellulose solutions and physicochemical characterization of regenerated cellulose films (scanning electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and thermogravimetric analysis) were performed. Cellulose solution prepared from 5% microcrystalline cellulose (w:v) in the solvent exhibits a Newtonian fluid character while cellulose solutions at higher concentrations show a pseudo‐plastic fluid behavior. Results from physicochemical characterization indicate that a freeze‐drying pretreatment step of cellulose leads to a complete dissolution at 5% concentration while only part of cellulose is dissolved at 10% and 15% concentrations. The results obtained indicated that the use of a freeze‐drying pretreatment step under mild conditions lead to a complete dissolution of cellulose at 5% concentration. The cellulose films prepared from 5% concentration exhibited desirable properties such as good optical transparency, crystallinity, and thermal stability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44871.