SynopsisWhen methyl methacrylate is polymerized in aqueous medium in the presence of gelatin, graft copolymer macromolecules with gelatine backbones and poly(methy1 methacrylate) (PMMA) grafts are formed. Due to the presence of graft copolymer, polymolecular micelles consisting of about 100 macromolecules are created. These micelles prevent macroscopic precipitation of PMMA. Fractionation in demixing solvents has been used to separate the components of the polymerization mixture, and the light-scattering method has been employed to determine their molecular weights. Each grafted macromolecule carries about one graft. The hypothesis of random grafting from gelatin backbones seems to explain most of the experimental observations.
SynopsisParameters characterizing the interaction of nonidentical polymer molecules in dilute solutions of mixtures of two polymers have been defined on the basis of Stockmayer's theory of light scattering in multicomponent systems. Various procedures for evaluation of the interaction parameters from experimental data have been compared. Specific features of the investigation of such interactions are demonstrated with the scattering behavior of the system polystyrene-poly-(methyl methacrylate)-dioxane.
The intensity of light scattered from dilute solutions of mixtures of two nonidentical polymers in a single solvent was measured. The parameter A24 characterising the thermo‐dynamic interaction of two nonidentical polymer molecules in solution was calculated for several systems polymer 2 ‐ polymer 4 ‐ solvent. For chemically strongly different polymers, A24 is independent of molecular weights of the polymers and probably also of solvent. A24 is related to the compatibility of both polymers and decreases contrary to expectation with increasing chemical difference between polymers 2 and 4.
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