Cellulose grafting by photoinduced controlled radical polymerisation†
The photoinduced controlled radical polymerisation (CRP) technique has been utilised to graft methyl acrylate (MA) and di(ethylene glycol) ethyl ether acrylate (DEGA) from filter paper. Grafting of MA was performed from α-bromoisobutyryl bromide functionalised papers. The amount of polymer grafted on the surface could be regulated by modifying the target DP of the reaction. SEC of cleaved linear polymer grafts showed that the grafting from filter papers proceeded with different kinetics compared to polymerisation from a free initiator added to the reaction mixture, resulting in higher dispersity. Furthermore, filter papers were polymerised with α-chloro-ε-caprolactone by surface-initiated ring opening polymerisation, yielding linear grafts containing initiating functions through-out the main chain. This functionality was subsequently utilised for the photoinduced CRP grafting of DEGA, yielding a graft-on-graft structure, which resulted in a thermoresponsive cellulose surface.