Pullulan-nanofibrillated cellulose composite films with improved thermal and mechanical properties

Novel bionanocomposite films with improved thermal and mechanical properties, were prepared by casting water-based suspensions of pullulan and nanofibrillated cellulose. The effect of the addition of glycerol, as a plasticizer, on the properties of the materials was also evaluated. The ensuing materials were characterized in terms of morphology, thermal stability, crystalline structure and mechanical properties. All bionanocomposites were very homogeneous, translucent and showed considerable improvements in thermal stability (increments of up to 20 degrees C in the degradation temperature) and mechanical properties (increments of up to 5500% and 8000% in the Young's modulus and tensile strength, respectively, for films plasticized with glycerol) when compared to the unfilled pullulan films. Additionally, these novel bionanocomposite could be labeled as sustainable materials since they were prepared entirely from renewable resources and through a green approach. (C) 2012 Elsevier Ltd. All rights reserved.