STUDY OF RADICAL METHYL-METHACRYLATE METHACRYLIC-ACID COPOLYMERIZATION IN ISOPROPYL-ALCOHOL BY DYNAMIC LASER SCATTERING AND C-13-NMR SPECTROSCOPY

The copolymerization of methyl methacrylate and methacrylic acid in is opropyl alcohol is studied by kinetic, dynamic laser scattering and C- 13-NMR methods. Correlations are established between the dependence of the copolymerization rate, the apparent average molecular weight, the diffusion coefficients and the configurational triad composition on t he monomer feed. These correlations and the fact that both copolymeriz ation constants are smaller than unity (r(MMA) = 0.63 +/- 0.03; r(MA) = 0.25 +/- 0.05) are in good agreement with the assumption that a como nomer complex takes part in the propagation reaction. A new Markov cha in method for the estimation of the configurational triad mole fractio n which accounts for the complex participation in a macromolecule form ation is developed. Qualitative criteria for evidence the participatio n of the comonomer complex in copolymerization are proposed using expe rimental and terminal model calculated mole fractions of the compositi onal triads and diads.