A novel approach to the study of extensional flow-induced crystallization

• Published in: Polymer testing Vol. 96; p. 107060
• Main Authors: Amirdine, Juliana, Htira, Thouaïba, Lefevre, Nicolas, Fulchiron, René, Mathieu, Nathalie, Zinet, Matthieu, Sinturel, Christophe, Burghelea, Teodor, Boyard, Nicolas
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-04-2021; Elsevier
• Subjects: Chemical Sciences; Extensional flow; Flow induced crystallization; Material chemistry; Modified SER fixture; Extensional flow; Modified SER fixture; Flow induced crystallization
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2021.107060

A systematic experimental investigation of the coupling between the extensional flow and the crystallization of a commercial grade polypropylene is presented. A modified Sentmanat extensional device allows one to generate a uniaxial extensional flow in the absence of gravity sagging and monitoring its effect on the kinetics of crystallization via in-situ visualization of the sample in polarised light. As compared to the shear induced crystallization, a three fold increase of the kinetics of the extension induced crystallization is found. The study is complemented by a post mortem analysis of the crystalline morphology by small angle X ray scattering (SAXS) and wide angle X ray scattering (WAXS).
•Custom design of a commercial Sentmanat extensional fixture mounted in a rotational rheometer.•Combination of measurements of the transient extensional viscosity with polarized light imaging.•Comparison of quiescent, shear-induced and extension-induced crystallization.•Post-mortem microstructure analysis by SAXS/WAXS on extended samples, according to Hencky strain rates.