KINETIC AND EPR STUDIES ON RADICAL POLYMERIZATION - RADICAL POLYMERIZATION OF DI-2[2-(2-METHOXYETHOXY)ETHOXY]ETHYL ITACONATE

摘要

The polymerization of di-2[2-(2-methoxyethoxy)ethoxy]ethyl itaconate (1) with dimethyl 2,2'-azobisisobutyrate (2) was studied, in benzene, kinetically and spectroscopically with the electron paramagnetic resonance (EPR) method. The polymerization rate (R(p)) at 50-degrees-C is given by the equation: R(p) = k[2]0.48 [1]2.4. The overall activation energy of polymerization was calculated to be 34 kJ.mol-1. From an EPR study, the polymerization system was found to involve EPR-observable propagating polymer radicals of 1 under the actual polymerization conditions. Using the polymer radical concentration, the rate constants of propagation (k(p)) and termination (k(t)) were determined. With increasing monomer concentration k(p) (1.5 approximately 4.3 L.mol-1.s-1 at 50-degrees-C) increases and k(t)(1.0.10(4) approximately 4.2.10(4) L.mol-1.s-1 at 50-degrees-C) decreases, which seems responsible for the high dependence of R(p) on the monomer concentration. The activation energies of propagation and termination were calculated to be 11 kJ.mol-1 and 84 kJ.mol-1, respectively. For the copolymerization of 1(M1) and styrene (M2) at 50-degrees-C in benzene the following copolymerization parameters were found: r1 = 0.2, r2 = 0.53, Q1 = 0.57, and e1 = + 0.7. [References: 26]