Deformation-Induced Phase Separation in Blends of Poly(ε-caprolactone) with Poly(vinyl methyl ether)

A study was conducted to investigate the microstructural evolution of poly(ε-caprolactone) (PCL)/poly(vinyl methyl ether) (PVME) blends at the nanoscale as a function of blend composition and deformation ratio at room temperature using the in situ synchrotron small-angle X-ray scattering (SAXS) technique. The introduction of noncrystallizable PVME into the amorphous regions of PCL resulted in a shift of critical strain where the fibrillation just sets in to larger value due to the reduced network modulus of the amorphous phase. A deformation-induced phase separation between PCL and PVME was also observed after lamellar-to-fibrillar transition. It was observed that the characteristics of the evolution of the microstructure in the systems during stretching followed a common scheme for semicrystalline polymers. Deformation-induced phase separation in the PCL/PVME blends was viewed as an important evidence for the occurrence of stress-induced fragmentation and recrystallization at large strains.