Effect of Relative Humidity on Mechanical Properties of Blended Chitosan-Methylcellulose Film

The effects of relative humidity (RH) on the mechanical properties of polymer films obtained by blending of chitosan-methylcellulose were investigated. The film samples were conditioned at various % RH for at least 48 h and then the mechanical properties were analyzed. The blended film achieved an optimum tensile strength (20.86 mPa) at 45.9% RH and elongation at break (52.4%) at 76.2% RH. Thermal properties and morphologies of the blended films were also studied. Melting points of the chitosan and methylcellulose films as examined by differential scanning calorimetry (DSC) were 115 degrees C and 118 degrees C, respectively. After blending of chitosan and methylcellulose the melting point of the blended film was lower than that of the individual film and the blended film had only one peak at 110 degrees C. This phenomenon shows that the blended chitosan-methylcellulose film forms a homogeneous mixture. Scanning electron microscopy (SEM) was used to characterize the morphology of the films. SEM images confirmed the homogeneous nature of the blended films.