Conventional and controlled radical polymerization redox-initiated by Cerium(IV) and Acrylamide as an intrinsically reducing inimer: a facile strategy to branched polyacrylamide

Since cerium(IV) ammonium nitrate (CAN) could oxidize amidyl N–H moieties into nitrogen-centered radicals under proper conditions to initiate radical polymerization, CAN-acrylamide (AAm) redox-initiated radical homo/co-polymerization in a conventional or controlled manner was exploited with AAm as an intrinsically reducing inimer. CAN oxidized AAm to initiate conventional radical homopolymerization at 50–60 °C, and viscosity-average molecular weight (MW) of polyacrylamide (PAAm) steadily increased with conversion because of the oxidation of amidyl N–H moieties of in-chain -AAm- units, but MW was in a range from 10 4 to 10 5 . CAN-AAm redox-initiated radical co-polymerization of N,N -dimethylacrylamide (DMAAm) proceeded readily under optimized conditions and formed PAAm-co-PDMAAm with MW in a range from 10 5 to 10 6 , and increasing simultaneously with conversion. CAN-AAm redox-initiated controlled radical homopolymerization was performed with FeCl 3 complexes as the deactivator, and the polymerization proceeded in a mechanism of reverse atom transfer radical polymerization (ATRP) and MW of PAAm increased in proportion to conversion. The PAAm chains contained a C–Cl terminal, which was confirmed by block co-polymerization with DMAAm via standard ATRP with PAAm as the macro-initiator.