Synthesis and Ring Opening Polymerization of a New Functional Lactone, α-Iodo-ε-caprolactone: A Novel Route to Functionalized Aliphatic Polyesters

A new functional lactone, alpha-iodo-epsilon-caprolactone (alpha I epsilon CL), was synthesized from epsilon-caprolactone by anionic activation using a non-nucleophilic strong base (lithium diisopropylamide) followed by an electrophilic substitution with iodine chloride. Ring-opening (co)polymerizations of the resulting monomer with epsilon-caprolactone were carried out using tin 2-ethylhexanoate as a catalyst in toluene at 100 degrees C. Homopolymerization of alpha I epsilon CL was achieved, and poly(alpha I epsilon CL) was fully characterized by SEC, H-1 NMR and elemental analysis. Random copolymerizations of alpha I epsilon CL with epsilon CL were controlled with experimental molecular weights close to the theoretical values, narrow molecular weight distributions and a good agreement between experimental and theoretical molar compositions of alpha I epsilon CL.