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Dynamic mechanical behaviour of a polysulfone in the glass transition region
Author(s) -
Macho E.,
Alberdi J. M.,
Alegría A.,
Colmenero J.
Publication year - 1988
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19880200147
Subject(s) - glass transition , dispersion (optics) , relaxation (psychology) , materials science , dynamic mechanical analysis , arrhenius equation , modulus , polysulfone , amorphous solid , fragility , thermodynamics , composite material , polymer , optics , chemistry , physics , activation energy , psychology , social psychology , organic chemistry
Dynamic mechanical measurements on commercial samples of a polysulfone have been performed at different frequencies at a temperature range from 400 to 510 K. Bending mode measurements were carried out in a Standard Polymer Laboratories DMTA apparatus, which simultaneously delivers both real and imaginary components of Young's complex modulus. Two main dispersion regions are apparent in the relaxation spectrum, the mechanical α‐relaxation, located at temperatures just above the calorimetric glass‐transition, and the high temperature dispersion process, which is related to the behaviour of the entanglement network. Master curves have been built from the experimental data. Shift factors corresponding to the two dispersion processes have been well fitted by only one Vogel‐Fulcher law. Below Tg, shift factor deviates towards an Arrhenius‐like behaviour which has been associated to a low strength sub‐Tg relaxation. Master curves allow the shape parameters of the two main dispersion processes to be calculated. Values obtained indicate that the dispersion process associated to the glass transition arises from a relatively high‐coupled intra‐cluster molecular motion with a nearly random cluster size distribution. However, the high temperature (low frequency) dispersion process seems to arise from the motion of units with weaker coupling.