Utilisation de l'analyse viscoélastique dynamique à l'étude de la cristallisation isotherme du poly(téréphtalate d'ethylène) amorphe. Application à des composites unidirectionnels avec fibres de verre

Abstract

Dynamic viscoelastic analysis was used to continuously follow the "cold crystallisation" of poly(ethy1ene terephthalate) (PET) test bars. Samples which were cut from an amorphous PET sheet were heated to a given temperature in a hot cell. The evolution of the real part of the modulus not only allows the kinetic crystallisation parameters but also the nucleation and growth characteristics to be determined. This method was applied to unidirectional PET/glass fibre composite strips. Thus, the influence of the glass fibres on the morphological and kinetic characteristics of the matrix crystallisation has been investigated.

Crystallization Behavior of Poly(ethylene terephthalate) Modified by Ionomers

“…Over the past decades, a great deal of efforts has been devoted to the discovery of nucleating agents or crystallization promoters, to accelerate the crystallization rate of PET, and a number of additives has been reported in the literature. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] For a few years, a detailed study of the effects of additives on crystallization behavior of PET was carried out in our laboratory. In our previous papers, [16 -19] the additives were divid into two kinds: one is nucleating agent, which can be used as a heterogeneous nuclei and effectively enhance nucleation rate of polymers in high temperature region; the other is nucleating promoters which are able to improve molecular motion of chains and promote primary nucleation of chains on the surface of nucleating agents and subsequently crystal growth.…”

Nucleation mechanism and crystallization behavior of poly(ethylene terephthalate) containing ionomers

“…[12] For PET reinforced with continuous glass fibers (fiber diameter = 14 lm), an increase in crystallization rate has been observed when crystallizing from the glassy state. [13] For PET filled with short glass fibers (length = 1 mm, diameter = 90 lm), a depression in crystallization rate has been found when crystallizing from the melt. [14] Kevlar fibers result in a greater increase in crystallization rate than glass fibers.…”

Evaluation of the sample temperature increase during the quiescent and shear-induced isothermal crystallization of polyethylene

“…This same relationship was used by Gauthier et al [9] for following the crystallization of poly(ethylene terephthalate)/glass fibre samples. They concluded that it allowed the evaluation of the crystallization kinetics and the determination of nucleation and growth characteristics.…”

“…In the work of Boutahar et al [10] and in other works [2,8,9], the results obtained from parallel rheometers for the isothermal crystallization are compared with similar DSC results. It is often found that the crystallization kinetics is comparable and even faster in a DSC than in a rheometer for the same crystallization temperatures (see for example the results shown in Fig.…”