Iron-Mediated AGET ATRP of Styrene in the Presence of Catalytic Amounts of Base

The first example of atom tramsfer radical polymerization using activators generated by electron transfer (AGET ATRP) of styrene in bulk and solution was investigated in the presence of catalytic amounts of NaOH or Fe(OH)3, using FeCl3·6H2O as the catalyst, (1-bromoethyl)benzene (PEBr) as the initiator, vitamin C (VC) as the reducing agent, and a cheap and commercially available tetrabutylammonium bromide (TBABr) or tetra-n-butylphosphonium bromide (TBPBr) as the ligand. It was found that both the polymerization rate and controllability over molecular weights and molecular weight distributions (∼1.2) of the resultant polymers could be enhanced in the presence of the catalytic amounts of base as compared with those without base. For example, the polymerization rate of bulk AGET ATRP with a molar ratio of [St]0/[PEBr]0/[FeCl3·6H2O]0/[TBABr]0/[VC]0/[NaOH]0 = 250/1/1/2/2/1.5 using NaOH as the additive was much faster than that without NaOH. The former was 3.5 times the latter. Furthermore, the polymerization of styrene could be successfully carried out even in the conditions when the amount of iron salts, FeCl3·6H2O as the catalyst, reduced to ppm level.