Kinetic and thermodynamic considerations in the synthesis of a new three-arm poly([epsilon]-caprolactone)

A new high-molecular-weight three-arm poly([epsilon]-caprolactone) (PCL) polymer was synthesized in bulk (in the absence of any solvent) by using aluminum tri-sec butoxide as a tri-functional initiator. The ring-opening polymerization of [epsilon]-caprolactone occurs via a coordination-insertion mechanism that links three growing polyester chains to the Al central atom via metal alkoxide bonds. The global kinetics of the bulk polymerization was determined, and a kinetic model based on monomer-polymer equilibrium was developed to predict the fractional extent of monomer conversion. Monomer conversions in excess of 95% to form high-molecular-weight PCL were achieved. Polym. Eng. Sci. 44:1491-1497, 2004. [c] 2004 Society of Plastics Engineers.
INTRODUCTION In recent years there has been mounting interest in the use of 'environmentally friendly' polymer materials that are biodegradable, recyclable, or derived from annually renewable resources. The rationale for [...]