Crystallization behavior of poly(.EPSILON.-caprolactone).

Abstract

The bulk crystallization behaviors of poly (e-caprolactone)-PCL have been studied by use of an optical microscope and differential scanning calorimetry. The crystallinity of PCL increased with a decrease in cooling rates during the cooling procedure from its melt; the feature was similar to the crystallization characteristics of polyolefin polymers in nonisothermal conditions. In isothermal crystallization, the linear growth rates of PCL spherulites were measured at various temperatures. The growth rate data obtained could be examined in terms of the kinetic theory of crystallization. Surface free energy of the PCL crystallite nucleus estimated from the kinetic data increased with increasing molecular weight. This implies that the fold surface of high molecular weight PCL crystallite would be covered with loose loop folds predominantly.