Crystallization and melting behavior of (ε-caprolactone)-based homopolymer and triblock copolymer

Abstract

The goal of this work is to examine the applicability of the Lauritzen-Hoflinan (LH) surface nucleation theory to the crystallization kinetics of poly(ε-caprolactone), PCL. This theory has successfully predicted a number of experimental observations such as the temperature dependence of spherulitic growth rates and the inverse relation between undercooling and the lamellar thickness. Claims have appeared in the literature that analysis of growth rate data using the LH theory does not yield physically meaningful parameters. This work will show that the lateral and fold interfacial free energy parameters, σ and σₑ, found by analysis with the LH theory are related to the chemical structure of the polymer chain in the case of PCL. The fold interfacial free energy is related to the chain stiffness, and a recent proposal relates σ to the characteristic ratio, C_∞. This work will examine the validity of the proposed relationship for the case of PCL. The effect of polymer chain architecture on the crystallization behavior was also investigated. The crystallization behavior of poly(ε-caprolactone) was compared and contrasted to that of a triblock copolymer containing (ε-caprolactone) blocks.