POLY(4-VINYLPYRIDINE) POLY(VINYL ACETATE-CO-VINYL ALCOHOL) BLENDS - EFFECT OF SEQUENCE DISTRIBUTION ON MISCIBILITY

The miscibility of blends of poly(4-vinylpyridine) (P4VP) with blocky copolymers of vinyl alcohol/vinyl acetate (ACA) of different compositi ons has been investigated and compared to that of the blends with rand om ACA copolymers. The miscibility window found in both cases is narro wer for the blocky ACA blends, indicating the influence of the comonom er sequence distribution. Fourier transform infra-red spectroscopy sho ws a lower level of pyridine-hydroxy hydrogen-bonding interactions in the case of blends with blocky ACA copolymers. Cloud point curves have been obtained from optical microscopy measurements for several P4VP/A CA blends. Finally, the binary interaction model including the influen ce of the copolymer sequence distribution has been applied using Balaz s and Cantow-Schulz approximations.