Study of Poly(methyl methacrylate) Stereocomplexes by Size Exclusion Chromatography and Dynamic Light Scattering

Poly(methyl methacrylate) stereocomplexes prepared in dilute tetrahydrofuran solutions were studied by size exclusion chromatography coupled with refractive index and light scattering detectors in combination with dynamic light scattering. In addition to the molecular/particle weight of the separated fraction and distribution of radius of the “viscosity” hydrodynamic sphere, the distribution of hydrodynamic radii was obtained as well. By mixing of iso- and syndiotactic polymers, a considerable increase in polymer particle mass was observed, while particle size varied much less. Consequently, an appreciable increase in the segment density of the particles was proved to be the result of stereocomplexation. This phenomenon was quantified by variation of the hydrodynamic shrinking factor (ratio of the “viscosity” radius of the complex particle and free poly(methyl methacrylate) molecule) during the separation. The results obtained support the picture of the stereocomplex particle as a structure with associated segments of different stereoregularity which should form branched, multifunctional points.