A comparison of the absolute reactivity of vinyl monomers. II

Abstract

The kinetics of polymerization of acrylamide (AM), acrylic acid (AA) and acrylonitrile (AN) initiated by the redox system, Mu³⁺ - isobutyric acid (IBA), was studied in the temperature range 30 - 50°C. Acrylamide and acrylic acid polymerization kinetics followed the same mechanism, viz., initiation by primary radical and termination by both Mn⁸⁺ ion and Mn³⁺ - isobutyric acid (intermediate) complex. But in acrylonitrile polymerization, termination by Mn³⁺ ion alone was observed. Also the complex termination step was found to be absent in acrylic acid polymcrization when the [Mn^3t] was kept very low. The rate coefficients k_p / k_u and k_J / k_o were related to the polymer radical reactivity and monomer reactivity respectively. It was found that while k_p / k_o follows the order AN > AA, the k_l / k_o follows the reverse order.