Evolution of the amorphous fraction of PEEK during annealing at atmospheric and high pressure above the glass transition temperature

Dasriaux, Marion; Castagnet, Sylvie; Thilly, L.; Chocinski–Arnault, Laurence; Boyer, Séverine A.E.

doi:10.1002/app.39297

Cited by 13 publications

(10 citation statements)

References 50 publications

(95 reference statements)

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“…degree of supercooling. This observation is also reported by other authors [9,22], with an increase in the first endothermic peak, which occurs 10°C above the annealing temperature attributed to the melting of the secondary crystallization. In fact, for high annealing temperatures, the diffusion process is very important, with a high mobility of chains allowing the crystalline phase to be enhanced.…”

Section: Hillier Parameter Modelingsupporting

confidence: 90%

A more reliable DSC-based methodology to study crystallization kinetics: Application to poly(ether ketone ketone) (PEKK) copolymers

Choupin

Fayolle

Régnier

et al. 2018

Polymer

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To quantify the isothermal crystallization kinetics of poly(ether ketone ketone) (PEKK), the integration of the crystallization peak measured using differential scanning calorimetry is rendered difficult due to the thermal transient effects at the start of enthalpy recording. The different attempts to extrapolate this peak beginning often lead to false values of the Avrami exponent. A new crystallization kinetic assessment method is established here based on the derivative of the Hillier crystallization kinetic model. This method consists of directly fitting the transformation rate to the heat flow of the experimental crystallization, thus avoiding the extrapolation of the crystallization peak beginning. This method is successfully applied to two different PEKK grades with different crystallization kinetics. The identified crystallization parameters are modelled as a function of the crystallization temperature, and based on these modeling results, time-temperature-transformation diagrams of crystallinity were built to provide a useful tool for PEKK processing.

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Section: Hillier Parameter Modelingsupporting

confidence: 90%

A more reliable DSC-based methodology to study crystallization kinetics: Application to poly(ether ketone ketone) (PEKK) copolymers

Choupin

Fayolle

Régnier

et al. 2018

Polymer

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“…The doublemelting behaviour was previously reported for PEEK [34][35][36] and for PEKK by Quiroga Cortes et al [21]. No influence of the annealing temperature was observed on the value of melting peak, indicating that primary crystalline phase is not sensitive to the annealing process [16,37]. The annealing endotherm indicates the melting of secondary crystalline phase.…”

Section: Annealed Paek Lmsupporting

confidence: 69%

“…The annealing endotherm indicates the melting of secondary crystalline phase. Their origin could be ascribed to the reorganization of amorphous phase in smaller crystallites rather than to the primary crystalline phase [37].…”

Section: Annealed Paek Lmmentioning

confidence: 99%

Thermal, mechanical and dielectric behaviour of poly(aryl ether ketone) with low melting temperature

Audoit

Rivière

Dandurand

et al. 2018

J Therm Anal Calorim

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New poly(aryl ether ketone)s (PAEKs) with a low melting temperature (relative to PEEK) are of interest in order to simplify the manufacturing of high-performance polymers or composites. In this study, we propose to investigate the physical properties of a new PAEK from Victrex, namely PAEK LM. Combinations of thermal analyses were used as follows: standard and modulated temperature differential scanning calorimetry, dynamic mechanical analysis, dynamic dielectric analysis and guarded hot plate technique. We found that the global mechanical, dielectric and thermal properties are very similar to the PEEK reference. The glass transition temperature was observed in the same range than PEEK (* 150°C) while the melting temperature T m was measured at 307°C for PAEK LM which is about 35°C below the melting temperature of PEEK. The degree of crystallinity of PAEK LM was found to be 27% while for PEEK it is 38%, depending on the processing conditions. This work explored crystalline structure-property relationships to explain the behaviour of PAEK LM.

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“…We observed that w 1 is closed to 1 for low temperatures and then decreases to values lower than 0.5 for temperatures above 260 C. This shows that the formation of the secondary crystallization is promoted for low degree of supercooling. This observation has also been reported by few authors [18,39] with the increase of a first endothermic peak which occurs 10 C above the annealing temperature attributed to the melting of the secondary crystallization. In fact, for high annealing temperatures, the diffusion process is very important with a high mobility of the chains allowing the enhancement of the crystalline phase by the growth of a second crystalline structure within lamellae.…”

Section: Isothermal Crystallization Kinetic Modelingsupporting

confidence: 66%

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

Choupin

Fayolle

Régnier

et al. 2017

Polymer

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a b s t r a c tIsothermal 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 1. 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.

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Evolution of the amorphous fraction of PEEK during annealing at atmospheric and high pressure above the glass transition temperature

Cited by 13 publications

References 50 publications

A more reliable DSC-based methodology to study crystallization kinetics: Application to poly(ether ketone ketone) (PEKK) copolymers

A more reliable DSC-based methodology to study crystallization kinetics: Application to poly(ether ketone ketone) (PEKK) copolymers

Thermal, mechanical and dielectric behaviour of poly(aryl ether ketone) with low melting temperature

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

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