Isothermal crystallization kinetic modeling of poly(etherketoneketone) (PEKK) copolymer

POLYMER

卷:111

Article

Choupin, T.^1,2  Fayolle, B.¹  Regnier, G.¹  Paris, C.²  Cinquin, J.²  Brule, B.³ 

[1] CNRS, CNAM, ENSAM, P1MM, 151 Blvd Hop, F-75013 Paris, France

[2] Airbus Grp Innovat, Dept Composites Mat, 12 Rue Pasteur, F-92150 Suresnes, France

[3] Arkema, Cerdato, Route Rilsan, F-27470 Serquigny, France

关键词: Thermoplastics;    Poly(etherketoneketone);    Thermal analysis;    Crystallization kinetic;    Crystallization induction time;    X-ray diffraction;   

DOI  :  10.1016/j.polymer.2017.01.033

来源: Elsevier

【 摘 要 】

Isothermal melt and cold crystallizations of a poly(etherketoneketone) (PEKK) copolymer prepared from diphenyl ether (DPE), terephthalic acid (T) and isophthalic acid (I) with a T/I ratio of 60/40 have been investigated by differential scanning calorimetry, wide-angle X-ray scattering and polarized optical microscopy. For the first time, the two-stage overall crystallization kinetics of PEKK taking into account effects of nucleation and crystal growth has been identified by using a modified Hillier type model. The primary crystallization stage is found to be an instantaneous two dimensional nucleation growth with an Avrami exponent of 2 whereas the secondary stage is found to be an instantaneous one dimensional nucleation growth with an Avrami exponent of I. The evolution of the crystallization kinetic constants for two-stage crystallizations has been modeled according to the Hoffman and Lauritzen growth theory. Due to low crystallization kinetics, a crystallization induction time has been added to obtain a good fit with experimental data. Based on this modeling, Time-Temperature-Transformation (TTT) diagrams of the relative volume crystallinity have been established for the overall crystallization mechanism and also for the separated primary and secondary crystallization mechanisms providing an original crystallization mapping of the material. (C) 2017 Elsevier Ltd. All rights reserved.

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