KINETIC AND STRUCTURAL EPR STUDIES OF RADICAL POLYMERIZATION - MONOMER, DIMER, TRIMER AND MIDCHAIN RADICALS FORMED VIA THE INITIATION OF POLYMERIZATION OF ACRYLIC-ACID AND RELATED-COMPOUNDS WITH ELECTROPHILIC RADICALS (CENTER-DOT-OH,SO4 RADICAL-ION AND CL2 RADICAL-ION)

A continuous-flow system has been used in conjunction with EPR spectro scopy to study the initial stages of polymerization of acrylic acid an d methacrylic acid in aqueous solution at pH 2 and 9, brought about wi th inorganic radicals (e.g. .OH) formed from metal-peroxide redox coup les. Structural characteristics of monomer adduct-radicals, as well as corresponding dimers and trimers, are reported, together with evidenc e for rapid intramolecular hydrogen-abstraction of the appropriate tet ramer to give a mid-chain radical. Computer-based simulation of steady -state concentrations leads to estimates of rate constants for initiat ion, propagation and termination reactions under these conditions.