Resumen de Controlled/Living Radical Polymerization in the Undergraduate Laboratories. 2. Using ATRP in Limited Amounts of Air to Prepare Block and Statistical Copolymers of n-Butyl Acrylate and Styrene

Krzysztof Matyjaszewski, Kathryn L. Beers, Zachary Metzner

• Developments in controlled radical polymerization have facilitated the use of living polymer chemistry in the undergraduate laboratories. In the first paper of this series, a procedure for the use of atom transfer radical polymerization (ATRP) to prepare block and statistical copolymers was described and the use of kinetic analysis to differentiate between living and conventional processes was demonstrated. In this paper, the experiment is extended to polymerizations run in limited amounts of air so that the use of inert gases is unnecessary. The Cu(I) catalyst can be lost owing to oxidation or termination reactions; however, a scavenger, Cu(0), is added to react with oxidized catalyst to regenerate the Cu(I) complex. A difunctional macroinitiator of poly(n-butyl acrylate) is prepared and chain-extended with polystyrene. A statistical copolymer using the same monomer pair is also prepared. These copolymers are isolated and characterized along with the homopolymeric macroinitiator using 1H NMR and SEC. Kinetic analysis is also carried out using GC and SEC. The significant difference in these two approaches, in addition to slight variations in the reaction conditions, is apparent in the chain extension to yield the ABA triblock copolymer.