DSC and FTIR studies on Gellan and Polyvinyl alcohol (PVA) blend films

Homopolymer films of Gellan and polyvinyl alcohol (PVA) and blended films were prepared by a solution casting method from a polymer solution in water of Gellan and PVA using glycerol as plasticizer. The films were studied for thermal characteristics by differential scanning calorimetry, for intermolecular interactions by Fourier transform infrared spectroscopy and for the mechanical properties of tear strength, tensile strength (TS) and percentage elongation (%E). A single melt isotherm for the blends and the shift of onset, melt temperatures of the blends and a change in glass transition were observed. A shift in the major signals of IR for OH absorption, and with varied intensities in the FTIR spectra indicated cross-linked interaction by the polymers. The blended films had TSs of 3.5–5.6 MPa and tear strengths of 15–30 g. The range of properties, both intermediate from the component polymers and extending beyond either individual components suggests molecular interaction and cross-linking within the blends.