? ?-Pentadecalactone (PDL) is a renewable monomer that can produce materials with properties similar to low-density poly(ethylene) as a consequence of a highly hydrophobic, long carbon chain backbone. Most ring-opening polymerizations rely on the positive enthalpy of ring-breaking to drive polymerization, however macrolactones such as PDL do not exhibit high ring-strains and are entropically-driven polymerizations. Catalysts that have been demonstrated to polymerize PDL require rigorously dry and often inert atmospheres in order to avoid initiation from water and ester hydolysis, that lead to large dispersities and low end-group fidelity. Herein, a relatively inexpensive magnesium-based catalyst is demonstrated for the 'immortal' ring-opening polymerization (ROP) of PDL. Successful polymerizations were shown under low catalyst loadings (0.5 mol% with regards to monomer). Furthermore, when reagents were not dried prior to use and ROP conducted under non-inert atmosphere, catalyst deactivation was not observed and polymerization still occurred. Materials produced through this 'benchtop' method displayed no side reactions as a consequence of the presence of water and displayed comparable dispersities and molecular weights to polymers produced in dry, inert conditions. Other solvents and bulk conditions were also shown to be effective in the production of poly(?-pentadecalactone). In addition to PDL, a range of other lactones were shown to polymerize 'immortally' through use of this catalyst.

"Immortal" ring-opening polymerization of ?-pentadecalactone in a non-inert environment

248th National Meeting (2014)

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