Competition between Phase Separation and Crystallization in a PCL/PEG Polymer Blend Captured by Synchronized SAXS,WAXS,and DSC

摘要

We conducted simultaneous,small-angle,X-ray scattering/differential scanning calorimetry (SAXS/ DSC) and simultaneous,wide-angle,X-ray scattering (WAXS)/DSC measurements for a polymer blend of poly(epsilon-caprolactone)/poly(ethylene glycol) (PCL/PEG).The time-dependent SAXS/DSC and WAXS/DSC results,measured while the system was quenched below the melting temperature of PCL from a melting state,revealed the competitive behavior between liquid-liquid phase separation and crystallization in the polymer blend.The time-dependent structural evolution extracted from the SAXS/WAXS/DSC results can be characterized by the following four stages in the PCL crystallization process: the induction (I),nucleation (II),growth (III),and late (IV) stages.The influence of the liquid-liquid phase separation on the crystallization of PCL was also observed by phase-contrast microscope and polarized microscope with 1/4lambda compensator.