TRIPLE-RESONANCE F-19, H-1, C-13 CPMAS NMR-STUDY OF THE INFLUENCE OF PMMA TACTICITY ON THE MISCIBILITY IN PMMA PVF2 BLENDS

Molecular miscibility in blends of poly(methyl methacrylate) (PMMA) with Poly(vinylidene fluoride) (PVF2) with isotactic, syndiotactic, and atactic PMMA was investigated by triple-resonance H-1, F-19, C-13 solid-state CPMAS NMR. From the fluorine to carbon cross polarization experiments the average distance between fluorines and OCH3 carbons in intimately mixed PVF2 and PMMA was estimated. Experimental evidence for a specific interaction between PVF2 and PMMA segments is presented. The proton to fluorine cross depolarization experiments Yield information on size and composition of the mixed PMMA/PVF2 phase. The fraction of nonmixed PMMA was determined for these blends, and it was found that this fraction was smaller for isotactic than for atactic and syndiotactic PMMA. Large differences in the amounts of isolated PMMA are observed between melt-mixed and coprecipitated blends.