Dynamic Study of Crystallization- and Melting-Induced Phase Separation in PEEK/PEKK Blends

Wu, Wei; Schultz, J. M.; Hsiao, Benjamin S.

doi:10.1021/ma970092l

Cited by 36 publications

(39 citation statements)

References 35 publications

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“…The same information can be obtained directly using electron microscopy. SAXS and electron microscopy investigations of polymer blends in which at least one component is crystallizable show that in some cases the interlamellar periodicity is significantly increased by the presence of the other component [4][5][6][7][8][9][10][11][12][13], and in some cases an increase in periodicity is either absent or weak [14][15][16][17]. The measurement of long periods using SAXS can be used to quantitatively assess the disposition of B between interlamellar and interfibrillar regions.…”

Section: Crystallization In Binary Polymer Blendsmentioning

confidence: 99%

“…Figure 14 illustrates an interesting kinetic effect which has been observed in several blend systems in which the components are rather similar. In this case differential scanning calorimetry has been performed during isothermal crystallization of poly(ether ether ketone) (PEEK), poly(ether ketone ketone)30/70 1) (PEKK(30/70)), and a 50/50 blend of these two polymers [38]. The time to reach the exothermic crystallization peak (or peaks) has been plotted against crystallization temperature for all three materials.…”

Section: Figure 11mentioning

confidence: 99%

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The crystallization and morphology of melt-miscible polymer blends

Schultz

2010

Front. Chem. China

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The morphology and kinetics of crystallization from melt-miscible blends is reviewed for binary systems in which either one or both polymer components are crystallizable. In systems in which one component (component A) crystallizes first, the other component (B) may reside finally between spherulites, between growth arms (composed of a stack of A crystalline lamellae), or between crystal lamellae of A. The kinetics of component redistribution dictates which site must become primary. It is shown that the diffusivity D of the components in the melt and the velocity V of spherulite growth combine through the diffusion length d = D/V to define the final location for component B and to also define whether spherulite propagation will be linear or parabolic in time. When crystallization of both components proceeds concurrently, by forming spherulites of A and of B, the spherulites are prone to interpenetrate or to form concentric spherulites. Cooperative crystallization, in which the kinetics of a rapidly crystallizing component and a slowly crystallizing component are both affected such that the two crystallize nearly simultaneously, is discussed. Finally, the competition between liquid-liquid phase separation and crystallization in systems with either an upper or lower critical solution temperature is reviewed.

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Section: Crystallization In Binary Polymer Blendsmentioning

confidence: 99%

Section: Figure 11mentioning

confidence: 99%

The crystallization and morphology of melt-miscible polymer blends

Schultz

2010

Front. Chem. China

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“…The discrimination methods use the solution of an equation based upon a given model and allow the simultaneous determination of Ea and g(x). Detailed kinetic analysis on plastics and on poly (ether ether ketone) can be found reported in the literature [13][14][15][16][17][18][19][20][21] . The present paper describes a kinetic study of the thermal degradation of poly (ether ether ketone) under dynamic conditions using an isoconversional and discrimination method.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of decomposition kinetics of poly (ether-ether-ketone) by thermogravimetric analysis

et al. 2013

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The non-isothermal thermogravimetric methods have been used extensively for the determination of kinetic parameters in polymers. The poly (ether ketones) are used as matrix in advanced high performance composites due its high thermal stability, excellent environmental performance and superior mechanical properties. In this work, the non-isothermal decomposition kinetics of the polymer poly (ether ether ketone) (PEEK) was evaluated in nitrogen and synthetic air atmospheres, using the Flynn-Wall-Ozawa and Coats Redfern models. The results showed that the necessary time for the material decomposes in 5% is approximately 216 years if it is submitted to temperatures of 350 °C in nitrogen atmosphere. On the other hand, if the material is submitted to air atmosphere, this decomposition time drops to about 1,05 years in the same temperature and for the same conversion rate. The decomposition kinetics study by Coats Redfern showed that the D3 mechanism (three-dimensional diffusion (Jander equation)) had better adjustment to the decomposition kinetics of the material in nitrogen atmosphere, while in synthetic air the R1 mechanism (phase boundary controlled reaction (one-dimensional movement)) has better adjustment to the decomposition kinetics of the material.

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“…Harris and Robeson 1 have reported that blends of various poly(aryl ether ketone)'s exhibit a window range where miscibility and isomorphic behavior may occur simultaneously, and they have also hypothesized that the range depends on the ketone content of the polymers. Using dynamic small-angle X-Ray scattering (SAXS) studies on the blend of PEEK/PEKK, Wang and Schultz et al 2 have concluded the for-mation of two separate lamellar stacks (PEEK and PEKK with 70% isophthalate moiety) co-existing in the spherulites of PEEK. Ji et al 3 reported the crystalline melting and morphism behavior of blends of poly(ether ether ketone) (PEEK) with poly(ether diphenyl ether ketone) (PEDEK).…”

Section: Introductionmentioning

confidence: 99%