Effects of poly(2-vinylpyridine) as a template for the radical polymerization of methacrylic acid—II: Influence of initiator concentration

The polymerization of methacrylic acid along an atactic poly(2-vinylpyridine) template was studied by varying the initiator concentration, I]₀. The concentrations of monomer and template were 0.4 M, the temperature 30°. Reaction rates were determined calorimetrically. The experimental results could be well described by a template polymerization model based on a modified mechanism omitting the requirement of a critical chain length of the oligomer radical prior to its association with the template. This view is in line with the existence of preferential adsorption of monomer by the template. In addition, the different ways of termination were also considered. By applying this kinetic model, the various radical concentrations and rate coefficients could be estimated. The termination rate coefficients for template associated polymer radicals appeared to be about 1000 times smaller than termination rate coefficient for non-associated radicals. Moreover, it was found that the initial polymerization rate has 0.26 order with respect to initiator, signifying a predominance of termination between template associated radicals over that between template associated and non-associated radicals (cross termination).