Simultaneous SAXS-WAXS Experiments on Semi-Crystalline Polymers: Example of PA11 and Its Brill Transition

Abstract

This manuscript of the special issue “Microstructural Evolution and Mechanical Behavior of Semi-Crystalline Polymers” aims to show that Small Angle X-ray Scattering (SAXS) and Wide Angle X-ray Scattering (WAXS) experiments performed simultaneously constitute a unique tool to obtain valuable information on the hierarchical structure of semi-crystalline polymers. These structural quantitative data are needed to model macroscopic properties of polymeric materials, for example their mechanical properties. To illustrate our point, we focus our study on the structure and morphology of polyamide 11. Through a simultaneous SAXS-WAXS experiment, we show that the absence of enthalpic signal in Differential Scanning Calorimetry (DSC) is not synonymous with the absence of structural and morphological evolution with temperature. The case of a thermally activated crystal–crystal transition, the Brill transition, is particularly detailed. Through this SAXS-WAXS study, we show, among other points, and for the first time, that the periodicity of crystalline lamellae (LP) changes at the transition, probably due to a modification of the amorphous phase’s free volume at the Brill transition. We also explain the crucial role of annealing to stabilize polymeric materials that may experience temperature changes over their lifetime. The influence of the annealing on the perfection of crystalline structure, morphology and mechanical behavior is more particularly studied.

Preparation and Single Crystal Structure Determination of the First Biobased Furan-Polydiacetylene Using Topochemical Polymerization

“…Crystals 2019, 9, x FOR PEER REVIEW 2 of 10 Development of new bio-based polymers requires characterization tools to gain better understanding of the material's structure and properties [26]. In this context, X-Ray Diffraction (XRD) techniques are widely applied [27][28][29]. These effective tools were also exploited in the case of furanbased polymers, which have been studied by many X-ray characterization techniques such as X-ray Powder Diffraction (XRPD) [30], X-Ray Fiber Diffraction (XRFD) [31], Wide-Angle X-ray Scattering (WAXS) [32], and Small-Angle X-ray Scattering (SAXS) [33].…”

Structural and Barrier Properties of Compatibilized PE/PA6 Multinanolayer Films

“…Simultaneously SAXS and WAXS [29] were also carried out at room temperature on stacked films with a respective thickness of 1, 1.6 and 2.5 mm in normal (ND), transverse (TD) and extrusion direction (ED), in order to optimize the scattered intensity. Since films are thin compared to the beam section (800 µm), stacking of film was necessary for ED and TD.…”

Evolution of mechanical properties of aged poly(ether ketone ketone) explained by a microstructural approach

“…The decomposition of the WAXS spectra in crystalline and amorphous components leads to the calculation of the weight crystallinity ratios [20] . Fig.…”

“…7 b, characterizes the crystalline lamellae organization. From these SAXS curves, we can calculate the correlation function of the electronic density and deduce the crystalline lamellar thickness (L c ) and periodicity (L P ) [20] . These data are reported in Fig.…”