Miscibility in blends of poly(vinyl acetate) with poly(methyl methacrylate) studied by FTIR and DSC

Miscibility in blends of poly(methyl methacrylate) (PMMA) with poly(vinyl acetate) (PVAc) has been studied by using differential scanning calorimetry and i.r. spectra techniques. PMMA is miscible with PVAc at all compositions. PMMA/PVAc blends show a lower critical solution temperature. The FTIR spectrum of a blend could not be obtained by adding spectra of the two pure components. There are spectral differences between miscible and immiscible blends either prepared by casting from tetrahydrofuran solution or phase separation. It is suggested that conformational changes resulting from hydrogen bond interactions between two similar polymers and solvents in solution are involved in miscible blends.