Simultaneous measurements of small angle x-ray scattering, wide angle x-ray scattering, and dielectric spectroscopy during crystallization of polymers

Abstract

A novel experimental setup is described which allows one to obtain detailed information on structural and dynamical changes in polymers during crystallization. This technique includes simultaneous measurements of small angle-wide angle x-ray scattering and dielectric spectroscopy (SWD). The capabilities of the technique have been probed by following in real time the crystallization process of a model crystallizable polymer: poly(ethylene terephthalate). By performing these experiments, simultaneous information from both, the amorphous and the crystalline phase is obtained providing a complete description of changes occurring during a crystallization process. The SWD technique opens up new promising perspectives for the experimental study of the relation between structure and dynamics in materials science.

Competition between phase separation and crystallization in a PCL/PEG polymer blend captured by synchronized SAXS, WAXS, and DSC

“…Especially, in time-resolved experiments a synchrotron radiation (SR) X-ray source, characterized by tremendously high photon flux and wide energy band, is usually indispensable. With the advances of X-ray sources and experimental techniques, SR X-ray scattering nowadays is often combined with other measurements such as DSC, 1-5 light scattering, 6 dielectric spectroscopy, 7 Raman spectra, 8 and infrared spectroscopy. 9 The integrated study for the structural characteristics, the thermal, electrical, and other physical properties of a sample system offers many advantages over individual experiment, particularly, in correlating structure characteristics with properties or in resolving or identifying a mechanism of, for instance, crystallization-related phase separation in polymer blends.…”

Structure–dynamics relationship during the amorphous to smectic transition of a main chain liquid crystalline polymer

“…A wavelength k = 0.15 nm was used for X-ray diffraction study. To enable simultaneous real time measurements of small-and wide-angle X-ray scattering, as well as of dielectric spectroscopy, a special designed cell was employed [10]. Details including experimental conditions, calibration and data reduction can be found elsewhere [11].…”

Localized translational motions in semicrystalline poly(ethylene terephthalate) studied by incoherent quasielastic neutron scattering

“…It is a non-Debye relaxation when observed in the frequency domain (stretched exponential decay in the time domain) and the temperature dependence of its relaxation times strongly departs from the common Arrhenius behaviour. The  relaxation dynamics of semicrystalline polymers, for instance as explored by means of dielectric spectroscopy DS, is affected by the presence of crystals, resulting in general in a less intense, broader and slower relaxation [8,[16][17][18][19][20]. In the context of semicrystalline polymers, poly(ethylene terephthalate) PET is one of the most common polymers for industrial necessities and, as a consequence, it has frequently attracted the attention from the scientific community during the last decades.…”