Authors Chen, J. ; Schneider, K. ; Heinrich, G.
Title In-situ synchrotron X-ray study on the structure variation of morphology-identified injection-molded ß-nucleated iPP under tensile deformation
Date 18.11.2021
Number 59805
Abstract The deformation behavior of semi-crystalline polymers is strongly dependent on the morphology formed during processing. In this study, in-situ synchrotron X-ray was firstly used to identify the morphological distributions of injection-molded isotactic polypropylene (iPP) with different concentrations of ß-nucleating agent. It was found that under relatively high concentration of ß-nucleating agent (i.e., =0.03 wt.%), the outer region (skin and shear region) of the iPP was dominated by mainly highly oriented a-phase as well as certain amount ·-phase, while the core region was rich in ß-crystals with little if any orientation. The addition of the ß-nucleating agent was beneficial for the formation of lamellae with large lamellar stacking distance in the shear layer. Then the synchrotron X-ray was applied to study the structure variation of those morphology-identified samples under tensile deformation. It was found that voids and cavities along the stretching direction existed in the deformed iPP samples and their volume increased with increasing concentration of ß-nucleating agent. The increased volume of void and cavity was associated with the ß to a phase transition, which mainly occurred at the core region. In addition, upon stretching crystalline fragmentation and rearrangement took place following the formation of thinner lamellae.
Journal Polymers
Citation Polymers 13 (2021) Article Number: 3730

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