Miscibility, crystallinity and morphological behavior of binary blends of poly(ethylene oxide) and poly(methyl vinyl ether–maleic acid)

DSC and optical microscopy were used to determine the miscibility and crystallinity of blends of poly(ethylene oxide) (PEO) with poly(methyl vinyl ether–co–maleic acid) (PMVE–MAc). Single Tg was observed for all blends, indicating miscibility. The dependence of Tg on the weight per cent of PEO presents a negative deviation from linearity at high PEO content, associated to a greater blend free volume, mobility and flexibility than in pure PEO. A progressive decrease in the degree of crystallinity and in the size of the PEO spherullites as the PMVE–MAc is added is observed. FTIR provided evidence of specific interaction between the polymers.