As the research interest in degradable polymers has risen, an ever increasing number of manuscripts report the synthesis of copolymers through ring-opening copolymerization techniques. However, the mechanism of copolymerization remains unexplored. In addition, the presence of transesterification reactions at higher conversions complicates the analysis of copolymer composition and monomer sequence distributions. To the best of our knowledge, all studies reporting reactivity ratios of ring-opening copolymerizations applied the terminal model with no analysis of the actual propagation method. We used quantitative 13C nuclear magnetic resonance to experimentally calculate the monomer sequence distribution of poly(caprolactone-co-valerolactone) copolymers. The sequence distributions indicated a statistical polymerization process, consistent with previous analysis of reactivity ratios and copolymer composition. This quantitative technique offers a rapid method to probe the mechanism of copolymerization of lactone monomers.
Proceedings Title: 244th ACS National Meeting, Polymer Chemsitry Division Preprints
Conference Dates: August 19-23, 2012
Conference Location: Philadelphia, PA
Conference Title: American Chemical Society Fall 2012 National Meeting & Exposition
Pub Type: Conferences