Magnetically controlled polymerization kinetics. polymerization of acrylamide using radicals generated in different spin states.

IGNACIO RINTOUL; CHRISTINE WANDREY

Niagara Falls, Ontario, Canada.

Conferencia; Polymer Reaction Engineering 7; 2008

Engineering Conferences International and American Institute of Chemical Engineers

Selected for poster presentation. Magnetic fields (MF) may open the possibility to optimize time, temperature regimes and productivity of radical polymerization processes in a non-contact, homogeneous, highly selective and instantaneous manner without modifying the final product composition, recipe formulations and other conditions related to traditional mass and heat transfer processes. A number of quantum mechanisms have been established and received proper theoretical treatment. However, the correlation between classical reaction kinetics and MF effects is still missing. The effect of MF on the radical solution polymerization of acrylamide (AM) was studied to establish basic criteria to modify the kinetics of polymerization by generation of free radicals in different spin states. Thermal and photochemically initiated polymerizations were investigated at different initiator and monomer concentrations, temperature, viscosity and MF intensity. The extent of MF effects on the kinetics of initiation, propagation and termination steps and its consequences on the overall polymerization rate expression were concluded. The polymerization rate was increased up to 65% when polymerizations were photochemically initiated in viscous media and performed at relatively low MF. MF effects were absent in thermally initiated polymerizations, polymerizations in low viscosity media and polymerizations performed at high MF. The effects can be explained in terms of the radical pair mechanism for intersystem crossing of spin states.