γ-Irradiation effects on the thermal and optical properties of undoped and eosin doped 70/30 (wt/wt%) PVA/glycogen films

Differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), UV/visible spectra and colour detection of pristine and gamma-irradiated undoped and eosin-doped 70/30 (wt/wt%) PVA/glycogen has been measured. The kinetic parameters such as the activation energy, entropy, enthalpy and free energy for all investigated samples were determined using Coats-Redfern relation. The shift of T-g position towards lower temperatures with increasing gamma-doses reflect that the degradation process is the predominant one. The values of absorbance and optical parameters in UV/visible range for gamma-irradiated blend sample doped with eosin showed no significant variation with increasing gamma-doses. This reflects that the addition of eosin to 70/30 (wt/wt%) PVA/glycogen makes it more resistant to gamma-radiolysis. The calculated colour parameters such as L-*, U-*, V-*, C-*, hue and Y-e were found to be dependent on addition of eosin and gamma-irradiation. (c) 2007 Elsevier B.V. All rights reserved.