D. Baeten1, V.B.F. Mathot1, M.F.J. Pijpers1, O. Verkinderen1, P. Van Puyvelde2, B. Goderis1
1Polymer Chemistry and Materials, KU Leuven, Heverlee, Belgium
2Soft Matter, Rheology and Technology, KU Leuven, Heverlee, Belgium
An in-situ FSC-SAXS/WAXD approach was used to study the isothermal crystallization of polyamide 11 (PA11) at different degrees of supercooling in order to elucidate its bimodal crystallization rate behavior with temperature . Time resolved WAXD analyses over the complete range of supercoolings revealed that mesomorphic material was produced in less than a second at high supercooling, whereas at very low supercooling crystals were obtained . The crystalline to mesomorphic ratio was found to increase gradually with increasing crystallization temperature. Analysis of the SAXS data supported the existence of a crystallization temperature dependent semicrystalline morphology composed of alternating solid and liquid-like layers with the solid layers made from crystalline, mesomorphic and rigid amorphous patches. Moreover, the crystalline or mesomorphic patches alternate with rigid amorphous patches in neighboring solid layers. The relation between details of this peculiar morphology and the crystallization rate as a function of the crystallization temperature will be discussed.
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 D. Baeten, V.B.F. Mathot, M.F.J. Pijpers, O. Verkinderen, G. Portale, P. Van Puyvelde, B. Goderis, Macromol. Rapid Commun. 36, 1184–1191 (2015) (link)