POLY(VINYLBUTYRAL-CO-VINYL ALCOHOL) TACTICITY AND ALUMINUM-OXIDE SURFACE-ADSORPTION

Solution-state C-13 NMR was used to study the mobility of poly(vinylbutyral-co-vinyl alcohol) (PVB) carbons in acetone-d(6), both in the presence and absence of aluminum oxide (alpha-alumina, Al2O3) powder. Apparent activation energies taken from variable-temperature T-1 spin-lattice relaxation measurements indicate that the dynamics of the aliphatic side chains and vinylbutyral backbone carbons are not affected by the presence of alumina. However, the dynamics of the vinyl alcohol sequences are influenced by alumina, which indicates that the alcohol groups experience an interaction with the alumina powder surfaces. This interaction is accompanied by a spectral line-shape change for the mesa (isotactic) methine carbon triads, which shows that tacticity has an influence on the adsorption process.