ORDERED STRUCTURES OF STEREOREGULAR POLY(METHYL METHACRYLATES) IN SOLUTIONS STUDIED BY SPECTROSCOPIC METHODS

Three groups of problems concerning ordered structures in solutions of stereoregular poly(methyl methacrylates) (PMMA) were studied by spectroscopic methods: (i) Self-aggregation of syndiotactic (s) PMMA in solution was followed by means of NMR and IR spectroscopy; it has been established that double helices are formed during the initial stage of aggregation, and activation and equilibrium thermodynamic parameters (DELTA-H, DELTA-S) which characterize the transition coil - double helix in s-PMMA were determined. (ii) NMR spectroscopy has demonstrated that association in solutions of atactic PMMA proceeds via interactions of stereocomplex type (interaction between m-diads and r-tetrads). (iii) It has been found that C-13 CP/MAS NMR spectra of crystalline forms of PMMA (prepared from aggregated solutions by solvent evaporation) conform to the double-helix structure of these systems.