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Effect of blend ratio on thermal and optical properties of poly (methyl methacrylate)/poly (vinyl acetate) films

F.H.Abd-El Kader, W.H.Osman, R.S.Hafez

Films of poly (methyl methacrylate) / Poly (vinyl acetate) (PMMA/PVAc) with different concentrations were prepared by using cast technique. The samples were investigated by differential thermal analysis (DTA), thermogravimetric analysis (TGA) and UV/visible spectra. A single glass transition temperature for each blend was observed in DTAthermograms, which reflects the existence ofmiscibility of such system. Thermogravimetric characterization and the calculated values of activation energies revealed that the blend sample of 75 wt% PVAc content has a more thermal stability than the other blends. The variation of band tail energywith the composition of the blend indicated that themodel based on electronic transitions between localized states is preferable. The refractive index dispersion curves were simulated by both Cauchy and single effective oscillator models. The calculated color parameters such as L*, U*, V*, and C* for 25 wt% PVAc blend sample were found to be dependent on addition of malachite green and ã-irradiation.