A dynamic study of crystallization of poly(ॉ-caprolactone) and poly(ॉ-caprolactone)/poly(vinyl chloride) blend

Abstract

The crystallization of poly(ε-caprolactone) (PCL) and a compatible blend of PCL with poly(vinyl chloride) were studied by a small angle X-ray scattering (SAXS) method with synchrotron radiation and by microscopic observation. By the SAXS method, the peak of the scattering intensity, arising from the long period in the sample, was observed during crystallization. The maximum intensity of the peak, Im, increased with crystallization time tc and reached a constant value Im(∞) at time 2τ1/2* (τ1/2* is the time necessary for Im to reach Im(∞)/2). The value of τ1/2* increased abruptly with an elevation of the crystallization temperature Tc for both pure PCL and the blend, and τ1/2* for the blend was larger than that for pure PCL at the same Tc. The change of Im against tc was analysed by the Avrami equation, the exponent n being about 2 for the blend at every Tc and pure PCL at higher Tc. For pure PCL at lower Tc, n increased with the decrease of Tc. In the microscopic observation of both pure PCL and the blend, the spherulite radius increased linearly with tc, and the linear growth rate G of spherulite decreased with Tc. A correspondence was found between Tc dependence of τ1/2* and that of 1/G. © 1986 The Society of Polymer Science, Japan.