Preliminary observations on the copolymerisation of acceptor monomer: Donor monomer systems under microwave irradiation

The mechanistic rationalisation of specific 'microwave effects' previously reported in a range of chemical reactions suggests that they may be observable in the free-radical copolymerisation of comonomer pairs capable of forming donor-acceptor complexes. Polymerisation under microwave irradiation is carried out for several comonomer pairs with weak donor-acceptor interactions, and no acceleration in rate or change in degree of alternation attributable to changes in propagation are observed. An increase in reaction rate of 150–200% is observed for all systems, with trends in molecular weight suggesting this was due to an increase in radical flux. This is consistent with earlier reports of rate enhancement for free-radical polymerisations using the initiator 2,2'-azobis-isobutyronitrile, and it is proposed that microwave irradiation may reduce the amount of geminate radical recombination.