Abstract
Stereoregular PMMAs have been adsorbed from solution on γ-alumina and studied by diffuse reflectance infrared (DRIFT) and solid state 13C NMR. Infrared has shown the fraction of surface bonded carbonyl (( ( c= O) ab ) is higher for the adsorbed isotactic PMMA than for the syndiotactic form. The shift of the infrared ν a may indicate that the methoxy functional group also interacts with the surface. From NMR spectroscopy, the changes in methylene carbon chemical shift, due to a lowering in the γ-gauche effect, are more pronounced for isotactic PMMA than for the syndiotactic form. The results agree with the assumption of a flattened conformation of adsorbed isotactic chains while atactic and syndiotatic chains are adsorbed more loosely.
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