Use of benzyl acetates as latent initiators for graft polymerizations using atom transfer radical polymerization (ATRP)

The polymerization of monomers with pendant atom transfer radical polymerization (ATRP) initiator sites leads to branched and hyperbranched polymers. To avoid this, the polymerization of monomers with masked ATRP initiator functionality, or `latent initiators', was investigated. These sites are not capable of initiating ATRP, but can be transformed into active ATRP sites in a later step. This approach allows isolation of the copolymer and rigorous characterization, after which the latent initiator sites can be unmasked and ATRP applied to the activated copolymer yielding the graft. The synthesis of random copolymer of styrene and acetoxymethyl styrene with predetermined molecular weight and narrow polydispersity using this method is described.