Bulk Ring-Opening Transesterification Polymerization of the Renewable δ-Decalactone Using an Organocatalyst.

The bulk ring-opening polymerization of renewable δ-decalactone using 1,5,7-triazabicyclo[4.4.0]dec-5-ene was carried out at temperatures between 7 and 110 °C. The equilibrium monomer concentration for reactions within this temperature range was used to determine the polymerization thermodynamic parameters (ΔHp = -17.1 ± 0.6 kJ mol-1, ΔSp = -54 ± 2 J mol-1 K-1) for δ-decalactone. The polymerization kinetics were established and high molar mass poly(δ-decalactone) was prepared with a glass transition temperature of -51 °C. Poly(δ-decalactone) samples with controlled molar mass and narrow molar mass distributions were realized by controlling the monomer conversion and initiator concentration. A high molar mass poly(lactide)-poly(δ-decalactone)-poly(lactide) triblock copolymer with a low polydispersity index was prepared by simple sequential addition of monomers. The product triblock exhibited two distinct glass transitions temperatures consistent with microphase segregation.