Average size of cooperative rearranging regions and fragility in a drawn poly(ethylene terephthalate) at the glass transition

Saiter, Allisson; Dargent, Éric; Saiter, Jean‐Marc; Grenet, J.

doi:10.1016/j.jnoncrysol.2007.07.044

Cited by 11 publications

(13 citation statements)

References 31 publications

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“…The main transition of polymeric materials can be better explained considering that various types of molecular motion, including local segmental motion (Brownian motion), sub‐Rouse, and Rouse modes, take place in the relaxation process . The size of the representative volume varies considering local motion or Rouse, i.e., small bonds of the main chain or subGaussian molecules, respectively.…”

Section: Resultsmentioning

confidence: 99%

Mechanical behavior and correlation between dynamic fragility and dynamic mechanical properties of curaua fiber composites

et al. 2013

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In this study, the mechanical properties and physical–chemical characteristics of curaua composites were evaluated using tensile and short beam testing and dynamic mechanical analysis. Curaua/polyester composites with different pretreatment (washing and drying), fiber length (10–50 mm) and fiber volume fraction (%Vf) (11, 22, and 38 vol%) were studied. The results show that the composites produced using 50 mm long washed/dried fibers and %Vf of 38 vol% achieved better mechanical properties, such as tensile strength and modulus and short beam strength. Fragility index “m” of the composites increased upon curaua incorporation, which may be attributed to a reduction in polyester chemical interactions (due to fiber dwelling of the polyester network). The energy required in initiating the cooperative motion at the “ideal” glass transition temperature and the cooperative rearrangement regions (CRR) also increased upon curaua incorporation, since CRR is considered the subsystem of the sample and for higher fiber content the greater the molecular heterogeneity. Finally, the Angell fragility concept was successfully applied to polymer composite systems. POLYM. COMPOS., 35:1078–1086, 2014. © 2013 Society of Plastics Engineers

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Section: Resultsmentioning

confidence: 99%

Mechanical behavior and correlation between dynamic fragility and dynamic mechanical properties of curaua fiber composites

et al. 2013

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“…The parameters calculated in this work are directly related to the equivalence of the WLF and VFT equations, since characteristic parameters of both models were discussed as described in the literature [7][8][9][10]. These parameters were obtained by inter-relations of the C 1 and C 2 constants of the WLF model [22,23].…”

Section: Dynamical Mechanical Analysis (Dma)mentioning

confidence: 99%

“…However, it is well-established that the determination of this temperature is always arbitrary, and there is no international convention on this subject [7]. Angell et al [8] proposed in estimating the relaxation time at 100 s by differential scanning calorimetry utilizing as heating rate 10 K/min.…”

Section: Introductionmentioning

confidence: 99%

“…According to Simon et al [12] in view of the fact that relaxation times diverge to infinite actually it is practically impossible to obtain equilibrium properties in the vicinity of the Kauzmann temperature (T k ). However, although it is not possible to reach equilibrium at these temperatures, it is possible to estimate this value by some experimental approach found in the literature [7][8][9][10]. According to Adam and Gibbs, [11] the "ideal" glass transition (T k ) can be obtained in two different ways: mechanical-statistical theories or extrapolations of the experimental data.…”

Section: Introductionmentioning

confidence: 99%

“…In this case, the properties of the glass are supposed to be directly correlated to the glass-forming liquid properties. There are several works directed to the correlation of these parameters; however, drawbacks are encountered when the goal is to correlate both quantities and microstructure [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of the epoxycyclohexyl polyhedral oligomeric silsesquioxane content on the dynamic fragility of an epoxy resin

Ornaghi

Pistor

Zattera

2012

Journal of Non-Crystalline Solids

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This study aims to evaluate the performance of epoxy/epoxycyclohexyl polyhedral oligomeric silsesquioxane nanocomposites focusing on differential scanning calorimetry and dynamic mechanical analysis. Nanocomposites with distinct nanoreinforcement contents (1, 2 and 5 wt.%) were studied. Using differential scanning calorimetry and dynamic mechanical analyses it was possible to assess some properties based on wellestablished concepts and correlate them with the structure formed. It was observed that the glass transition temperature decreases following the incorporation of epoxycyclohexyl polyhedral oligomeric silsesquioxane, indicating, in principle, that there is more mobility in the new system formed. However, other calculated parameters (cooperative rearrangement region, Angell fragility and Kauzmann temperature) showed no trend as a result of epoxycyclohexyl polyhedral oligomeric silsesquioxane incorporation.

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Structural development in ion‐irradiated poly(ether ether ketone) as studied by dielectric relaxation spectroscopy

Lafi

2013

J of Applied Polymer Sci

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Structural alterations to amorphous poly(ether ether ketone) (PEEK) produced by ion irradiation (11.2 MeV H 1 and 25.6 MeV He 21 ions) were investigated by dielectric relaxation spectroscopy. The analysis in terms of the Havriliak-Negami (HN) equation and the scaling model showed an increase in the intermolecular correlation with increasing irradiation dose. The dynamic fragility index (m) was estimated from Vogel-Fulcher-Tammann analysis. Ion irradiation not only elevated the glass-transition temperature (T g ) but interestingly decreased m of the PEEK chains around T g . This was due to increasing polar interaction and better packing efficiency of the irradiated samples compared with those of amorphous PEEK. The average size of the cooperative rearranging region decreased in line with decreasing m and indicated an increase in the rigid amorphous phase fraction after irradiation. The analysis of the direct-current conductivity confirmed that there was a strong coupling between the macroscopic ion transport and concerted segmental motion.

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Average size of cooperative rearranging regions and fragility in a drawn poly(ethylene terephthalate) at the glass transition

Cited by 11 publications

References 31 publications

Mechanical behavior and correlation between dynamic fragility and dynamic mechanical properties of curaua fiber composites

Mechanical behavior and correlation between dynamic fragility and dynamic mechanical properties of curaua fiber composites

Effect of the epoxycyclohexyl polyhedral oligomeric silsesquioxane content on the dynamic fragility of an epoxy resin

Structural development in ion‐irradiated poly(ether ether ketone) as studied by dielectric relaxation spectroscopy

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