Blending, grafting, and cross-linking processes between poly(ethylene oxide) and a (4-benzoylphenoxy)∼0.5(methoxyethoxyethoxy)∼0.5phosphazene copolymer

We report our results on the miscibility and irradiation of the blends of poly(ethylene oxide) (PEO) and a phosphazene copolymer almost equimolecularly substituted with 4-benzoylphenoxy and methoxyethoxyethoxy moieties (BzMEEP). Differential scanning calorimetry (DSC) studies of the blends showed glass transitions temperatures (T-g) that increased regularly with the percentage of BzMEEP in the blend from about -50 degrees C up to -30 degrees C. Irradiation of these blends, under selected experimental conditions, leads to the absorption of the light by the benzophenone chromophore only in the copolymer, causing grafting of PEO onto the copolymer to occur concurrently with cross-linking reactions. Almost completely insoluble gellike materials were obtained. The percent of gel formed and degree of swelling of the cross-linked blends in chloroform were dependent on the amount of benzophenone, irradiation time, and molar mass of PEG.