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

The bulk ring-opening polymerization of renewable delta-decalactone using 1,5,7-triazabicyclo[4.4.0]dec-5-ene was carried out at temperatures between 7 and 110 degrees C. The equilibrium monomer concentration for reactions within this temperature range was used to determine the polymerization thermodynamic parameters (Delta H-p = -17.1 +/- 0.6 kJ mol(-1), Delta S-p = -54 +/- 2 J mol(-1) K-1) for delta-decalactone. The polymerization kinetics were established and high molar mass poly(delta-decalactone) was prepared with a glass transition temperature of -51 degrees C. Poly(delta-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(delta-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.