RAFT-mediated polymerization and grafting of sodium 4-styrenesulfonate from cellulose initiated via gamma-radiation

Ambient temperature (20 degrees C) reversible addition fragmentation chain transfer (RAFT) polymerization of sodium 4-styrenesulftonate (SS) conducted directly in aqueous media under gamma-irradiation at different dose rates (0.09, 0.03 and 0.02 kGy h(-1)) proceeds in a controlled fashion (typically, M-w/M-n < 1.25) to near quantitative conversions via 4-cyanopentanoic acid dithiobenzoate (CPADB) mediation. By applying CPADB modified cellulose as a macro chain transfer agent, a graft copolymer with SS was prepared in aqueous media under gamma-irradiation. RAFT mediated graft polymerizations provided copolymers with higher graft frequencies compared to those obtained by conventional methods. Thermally initiated grafting of SS from a CPADB-functionalized cellulose surface at 70 degrees C was also studied which resulted in a reduced graft frequency in comparison to gamma-initiated ones.