Deformation behavior of banded spherulite during drawing investigated by simultaneous microbeam SAXS-WAXS and POM measurement

The local deformation behavior inside a poly(ε caprolacton) (PCL)/polyvinylbutyral (PVB) banded spherulite during drawing was observed by in-situ microbeam small-angle X-ray scattering (SAXS) - wide-angle X-ray scattering (WAXS) - polarized optical microscopy (POM) simultaneous measurements. From experimental results, we found that the local deformation of a PCL/PVB banded spherulite can be divided into four stages. In stage I, disordering of the crystalline structure occurs. In stage II, the disordering of the crystalline structure ceases and disordering of the stacking and coarse slippage of the lamellae occur. In stage III, after the breakdown of the twisted lamella structure, the reconstruction of a long period structure occurs. In stage IV, further lamella slippage occurs. Our results show no evidence of fine slippage at a local region during the drastic decrease in the long period. This strongly indicates that the melting and recrystallization mechanism occurs during the lamella reconstruction of PCL/PVB.