Kinetics of ε-Caprolactone Ring Opening Polymerization: Experimental and Modeling Study

Abstract

Although polycaprolactone (PCL) is an established biodegradable polymer with various applications, comprehensive kinetic modeling of its production is very rare. We present a multi-scale model of ring-opening polymerization (ROP) of epsilon-caprolactone catalyzed by tin(II) octoate as a standard industrial method of PCL production. Five batch polymerization experiments with varying temperature and monomer/initiator ratio were conducted, leading to the production of linear PCL samples of varying molecular weight distributions. The experimental data were subsequently used for the rigorous estimation of kinetic parameters associated with the elementary reaction steps in the assumed kinetic scheme. The results of the model predictions are compared with experimental data with decent agreement, revealing that although the reaction dynamics are significantly slower for ROP of epsilon-caprolactone than for L,L-lactide, the original kinetic scheme previously validated for polylactide production can be successfully used to model the PCL production process.