Association of stereoregular poly(methyl methacrylates) in dilute solution. Proton NMR study

By measurement of integrated intensities of high-resolution proton nuclear magnetic resonance (NMR) bands, associated structures of isotactic (i) and syndiotactic (s) poly(methyl methacrylate) (PMMA) in dilute toluene-d₈ and dimethylformamide-d₇ solutions were detected and characterized. In 1% (w/v) solutions of highly stereoregular s-PMMA in toluene-d₈ at 27°C, 76% of the monomer units are present in the form of compact aggregates. Consequences of this finding for the polymerization of methyl methacrylate in toluene in the presence of s-PMMA are discussed.