Effect of glycerol plasticizer on the structure and characteristics of bacterial cellulose-based biocomposite films

Biocomposite film was successfully produced by combining bacterial cellulose (BC) and sodium alginate (ratio of 80:20) with the addition of glycerol as conventional plasticizer at varied concentration (2, 4, 6% w/w, based on total sample weight) through solution casting method. The influence of glycerol content on structure (by FTIR), mechanical properties, optical properties (by colorimeter and spectrophotometer) and water vapor permeability (WVP, gravimetric method) of BC biocomposite film was investigated. The addition of glycerol disrupts the inter- and intramolecular hydrogen bonds in the cellulose chains, replaced by weaker BC-alginate-glycerol bonds. This resulted a decrease in film density, causing lower tensile strength, lightness, opacity and WVP of BC biocomposite film. An increase in glycerol concentration led to an increase in elongation percentage due to the effect of glycerol plasticization. Film with 4% glycerol exhibited the lowest WVP (5.08x10-13 g/m.s.Pa), highest lightness (L = 73.49), lowest opacity (3.24 Abs/mm) with tensile strength of 19.57 MPa and elongation 8.38%. The addition of glycerol significantly affects the BC biocomposite film properties. The resulting biofilm shows performance equivalent to commercial bioplastic TeloRoll.