✦ LIBER ✦

Variation in Activation Energy of the Glass Transition for Polymers of Different Dynamic Fragility

✍ Scribed by Sergey Vyazovkin; Nicolas Sbirrazzuoli; Ion Dranca

Publisher: John Wiley and Sons
Year: 2006
Tongue: English
Weight: 106 KB
Volume: 207
Category: Article
ISSN: 1022-1352
DOI: 10.1002/macp.200600095

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Summary: Variations of the effective activation energy E of glass transitions have been determined by applying an isoconversional method to DSC data on the glass transition in PVC, PBMA, PVP, and PEN. A variability parameter Δ~E~ has been introduced to characterize the rate of decrease in E with increasing temperature. By using the present data and our previous results for PS, PET, and B~2~O~3~, it has been found that Δ~E~ correlates with the values of dynamic fragility, increasing with the latter in approximately exponential fashion.

Correlation of the variability parameter with the dynamic fragility.

imageCorrelation of the variability parameter with the dynamic fragility.

📜 SIMILAR VOLUMES

Variation of the Effective Activation En

Variation of the Effective Activation Energy Throughout the Glass Transition

✍ Sergey Vyazovkin; Nicolas Sbirrazzuoli; Ion Dranca 📂 Article 📅 2004 🏛 John Wiley and Sons 🌐 English ⚖ 129 KB

## Abstract Summary: An advanced isoconversional method has been applied to determine the effective activation energies (__E__) for the glass transition in polystyrene (PS), poly(ethylene terephthalate) (PET), and boron oxide (B~2~O~3~). The values of __E__ decrease from 280 to 120 kJ · mol^−1^ in

Ductile and brittle behavior of amorphou

Ductile and brittle behavior of amorphous polymers. Relationship with activation energy for glass transition and mechanical fracture

✍ Shaul M. Aharoni 📂 Article 📅 1972 🏛 John Wiley and Sons 🌐 English ⚖ 615 KB

On the glass transition in ultrathin pol

On the glass transition in ultrathin polymer films of different molecular architecture

✍ Oswald Prucker; Stefan Christian; Harald Bock; Jürgen Rühe; Curtis W. Frank; Wol 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 939 KB

Modification of the integral isoconversi

Modification of the integral isoconversional method to account for variation in the activation energy

✍ Sergey Vyazovkin 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 158 KB 👁 2 views

Integral isoconversional methods may give rise to noticeable systematic error in the activation energy when the latter strongly varies with the extent of conversion. This error is eliminated by using an integration technique that properly accounts for the variation in the activation energy. The tech

Fine structure of the glass transition i

Fine structure of the glass transition in amorphous polymers. Part 2. Interpretation of the G″ peak and J″ peak by different molecular motion

✍ E. Donth; K. Schneider 📂 Article 📅 1985 🏛 John Wiley and Sons 🌐 English ⚖ 646 KB

Modulated differential scanning calorime

Modulated differential scanning calorimetry in the glass transition region. V. Activation energies and relaxation times of poly(ethylene terephthalate)s

✍ Iwao Okazaki; Bernhard Wunderlich 📂 Article 📅 1996 🏛 John Wiley and Sons 🌐 English ⚖ 972 KB

Temperature-modulated differential scanning calorimetry is used to evaluate the kinetics of the glass transition from measurement of the first harmonic of the apparent, reversing heat capacity. The data are taken from quasi-isothermal experiments with negligible instrument lag, extrapolated to zero