Effect of molecular weight on the spherulitic growth rate of poly(aryl ether ether ketone)

Deslandes, Yves; Sabir, Frank-Nid; Roovers, Jacques

doi:10.1016/0032-3861(91)90231-7

Cited by 32 publications

(30 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fold surface free energy σ e of PEEK 150G, 450G, and 650G for regime II (filled red circles) and regime III (filled blue squares) as a function of inverse number‐average molecular weight (1/ M n ) compared with Deslandes's work (open black circles) …”

Section: Resultsmentioning

confidence: 99%

“…The poor solubility of PEEK hinders use of typical molecular characterization methods, such as intrinsic viscosity and size exclusion chromatography (SEC). Thus, only a few studies on PEEK crystallization behavior have been conducted with consideration of molecular weight . Since PEEK is a condensation polymer, PEEK has a relatively small number of repeat units compared to polyolefins.…”

Section: Introductionmentioning

confidence: 99%

“…Most studies on PEEK crystallization have been conducted at high crystallization temperatures (T c > 270 C) [5,8,14,17,19,[21][22][23]30,33,34] or at low crystallization temperatures (T c < 190 C). [5,8,34] In the middle temperature range (190 C < T c < 270 C), PEEK crystallization cannot be monitored by conventional DSC because of too high crystallization rates. [29,31,35] Moreover, PEEK is insoluble in all classical organic solvents at room temperature.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Isothermal crystallization of poly(ether ether ketone) with different molecular weights over a wide temperature range

Seo

Gohn

Dubin

et al. 2019

Polymer Crystallization

View full text Add to dashboard Cite

A systematic investigation to determine the importance of molecular weight on the isothermal crystallization kinetics of PEEK across a broad temperature range is presented for three commercial PEEKs (Victrex 150G, 450G, and 650G). The Avrami crystallization model is fit to the isothermal crystallization kinetics of PEEK as a function of crystallization time. To describe the secondary crystallization kinetics, a modified Avrami model is suggested by introducing a second Avrami exponent. The primary and secondary Avrami exponents of PEEK are 3.3 ± 0.4 and 2.3 ± 0.3. Using both standard differential scanning calorimetry (DSC) and fast scanning chip calorimetry (FSC), isothermal PEEK crystallization kinetics are investigated in a wide range of crystallization temperatures (158°C < T c < 336°C). As the molecular weight is increased, the crystallization kinetics decrease. The crystallization half‐times from DSC and FSC are well described by the Hoffman‐Lauritzen model over the entire range of possible crystallization temperatures.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Isothermal crystallization of poly(ether ether ketone) with different molecular weights over a wide temperature range

Seo

Gohn

Dubin

et al. 2019

Polymer Crystallization

View full text Add to dashboard Cite

show abstract

“…Great difficulties are encountered when trying to justify our experimental results with the reverse picture (i.e., L a > L c ). Small increases of the equilibrium melting temperature T m 0 with increasing average molecular weight have been suggested for these PEEK fractions 38 and would result, for the same crystallization temperature, in larger degrees of supercooling for increasing molecular weights. According to Tamman's equation, this would lead to an decrease of L c with increasing average molecular weight which cannot be reconciled with the hypothesis that L c > L a .…”

Section: Discussionmentioning

confidence: 98%

Cold Crystallization of Narrow Molecular Weight Fractions of PEEK

et al. 1999

View full text Add to dashboard Cite

Several amorphous narrow molecular weight fractions of poly(aryl ether ether ketone) or PEEK have been heated from below their glass transition temperature to above their final melting point. The semicrystalline morphology induced by cold crystallization and its thermal evolution are studied by time-resolved simultaneous small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction, and differential scanning calorimetry. The long period and the crystalline and the amorphous thicknesses are computed from the correlation function of the SAXS curves. The evolution of the structural parameters of the various semicrystalline samples can be reconciled with the existence of a single distribution of lamellae which undergoes reorganization during the continuous heating. The reorganization process as well as the semicrystalline morphology depends on the molecular weight of the fractions. The amorphous thickness strongly increases with the molecular weight while the thermal evolution of the thickness of the crystalline layers is similar for all fractions. These experimental results support the view that the larger degree of entanglements of the high molecular weight samples impedes the reorganization mechanism with the consequence that the apparent melting temperature decreases with increasing average molecular weight.

show abstract

“…[15] For the nonionic homopolymers, PET-1 and -2, there is a slight increment of s e with the molecular weight, as already observed for other polymers. [33,34] In any case, it is possible to observe that the s e values found for PET ionomers are located in the s e range of homopolymers, with a small increment corresponding to the possible increment of the molecular weight due to the ionic associations. As s e is strictly connected to the work of chain folding, i.e., the work required to bend the polymer chain back upon itself, [35] the results obtained suggest that in telechelic ionomers, the chain folding is not modified, and the flexibility of the macromolecules does not change.…”

Section: Overall Crystallization Kineticsmentioning

confidence: 95%

Modification of PET by Reactive Blending with Sulfonated Esters. II. Isothermal Crystallization Kinetics of PET-Ionomers

Berti

Celli

Colonna

et al. 2003

Journal of Macromolecular Science, Part B

View full text Add to dashboard Cite

The thermal properties of PET-ionomers, obtained by reactive blending between PET and a monofunctional ester containing an ionic group (ZSO 3 Na), were studied using DSC, and results were compared with those of nonionic PET homopolymers. The presence of ionic groups located only at the chain ends induces significant modifications in the thermal behavior: the equilibrium melting temperature increases and the crystallization rate decreases with the ionic group content; moreover, the crystalline level remains high. All of these characteristics are interpreted as due to ionic associations between the sulfonated end groups, both in solid and in molten states, that cause an apparent increment in the molecular weight of ionomers. A confirmation of this simple molecular architecture is found in the growth regime analysis: the foldsurface free-energy values of ionomers do not vary compared to those of nonionic homopolymers, indicating that chain folding is not hindered by the presence of a complex network.

show abstract

Effect of molecular weight on the spherulitic growth rate of poly(aryl ether ether ketone)

Cited by 32 publications

References 31 publications

Isothermal crystallization of poly(ether ether ketone) with different molecular weights over a wide temperature range

Isothermal crystallization of poly(ether ether ketone) with different molecular weights over a wide temperature range

Cold Crystallization of Narrow Molecular Weight Fractions of PEEK

Modification of PET by Reactive Blending with Sulfonated Esters. II. Isothermal Crystallization Kinetics of PET-Ionomers

Contact Info

Product

Resources

About