Synchrotron X-ray scattering applications in crystallization and deformation of polymers

The combined techniques of simultaneous small- and wide- angle x-ray scattering (SWAXS) using synchrotron radiation are one of the best tools to investigate the morphology and structure changes during phase transition and deformation of polymers in real time and in-situ. In this talk, we will use two example studies to demonstrate the powerful potential of the SWAXS techniques. The first study involves isothermal crystallization of poly(oxymethylene), POM, homopolymer and blends with high and low glass transition temperature (Tg) plasticizers. Many lamellar variables such as lamellae long period, lamellar thickness, interlamellar amorphous thickness and invariant have been estimated to examine the lamellar morphology having a diluent inclusion or exclusion structure. The second example involves the deformation of a solvent cast isotropic polyurethaneurea film. The continuous changes of SAXS patterns from an isotropic ring at no stress to a distinct four-spot pattern when stress is 200% reveal the nature of the nanophase separation during deformation. A two-spot layer line pattern is further observed when the stress is increased to 250%, indicating the destruction of some regions of hard segment domains. This damage results in a non-recoverable change in the SAXS pattern from the relaxed film.