INTERPOLYMER COMPLEXATION AND BLEND FORMATION BETWEEN POLY(N-VINYL-2-PYRROLIDONE) AND ALIPHATIC HYDROXYL-CONTAINING POLYMERS

The interpolymer complexation and blend formation between poly(N-vinyl -2-pyrrolidone) (PVP), a tertiary amide polymer, and three aliphatic h ydroxyl-containing polymers, namely, poly(2-hydroxypropyl methacrylate ), poly(hydroxyether of bisphenol-A) and poly(styrene-co-allyl alcohol ), has been studied. PVP forms interpolymer complexes with all the thr ee aliphatic hydroxyl-containing polymers in tetrahydrofuran solutions over the entire feed composition range. The glass transition temperat ures of the complexes are higher than those calculated from the additi vity rule. PVP has a stronger ability in forming interpolymer complexe s with aliphatic hydroxyl-containing polymers than the other three ter tiary amide polymers, namely, poly(N-methyl-N-vinylacetamide), poly(N, N-dimethylacrylamide), and poly(2-ethyl-2-oxazoline). Infrared spectro scopic studies show that the hydrogen bonding interactions between the carbonyl groups in PVP and the hydroxyl groups are stronger than the self-associations of the hydroxyl-containing polymers. Semiempirical A ustin Model 1 (AM1) calculations reveal that the atomic charges of the carbonyl oxygen atoms of all these tertiary amide polymers are about the same, suggesting that steric factor is important in determining th eir complexation behavior.