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Phénomènes cinétiques associés à la transition vitreuse du polyisoprène de structure 1,4 prépondérante

✍ Scribed by Prud'homme, Jacques ;Goursot, Paul ;Laramée, André

Publisher
Wiley (John Wiley & Sons)
Year
1977
Weight
710 KB
Volume
178
Category
Article
ISSN
0025-116X

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✦ Synopsis

Abstract

The thermal behavior of polyisoprene with a high content of 1,4 structures prepared by anionic polymerization has been investigated in the glass transition interval by means of differential scanning calorimetry (DSC). This polymer is of particular interest since it has a low glass transition temperature T~g~ and shows a substantial increase in heat capacity in the glass transition interval. When the thermal history of the polymer is fixed by linear cooling, the dependence of T~g~ (measured at the inflexion point of the experimental curve) on heating rate q, can be expressed by q=constant × exp{−E/(RT~g~)} where E varies from 127 to 144 kJ/mol when the cooling rate decreases from 80 to 1.25 K/min. It is shown that this behavior is consistent with a kinetic model for glass transition involving a simple relaxation process characterized by an energy of activation close to E.

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