Nonisothermal crystallization of compatible PCL/PVC blends under supercritical CO2

Abstract

Nonisothermal crystallizations of polycaprolactone (PCL) in the presence of poly(vinyl chloride) (PVC) at a cooling rate of 0.5°C/min from 90 to 30°C under supercritical CO2 at a constant pressure 304 atm were investigated. DSC and SAXS data found that the nonisothermal crystallizations of the PCL/PVC blends under super-critical CO2 resulted in decrease in thickness of the crystalline layers in the lamellar stacks. These nonisothermal super-critical CO2 treatments also generated a morphological heterogeneity with size (13.8 nm for pure PCL) larger than the long period (12.1 nm) of the lamellar stacks. The size of this heterogeneity was slightly enhanced from 13.8 nm for pure PCL to 15.2 and 16.3nm for the blends containing 10 and 25 wt% PVC, respectively.