Nonisothermal crystallization of compatible PCL/PVC blends under supercritical CO₂

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.