Matériaux & Techniques
Volume 83, Number 5-6, 1995
|Page(s)||17 - 30|
|Published online||13 April 2017|
Matériaux composites à matrice organique
Propriétés thermomécaniques des matrices et mise en œuvre
Organic matrices for composites: thermomechanicaland processing properties
Ecole Nationale Supérieure d’Arts et Métiers (ENSAM), Paris
Some important properties of organic matrices are reviewed. The thermal stability ceiling depends essentially on the dissociation energy of the weakest bond of the monomer unit and the eventual existence of a mechanism of chain propagation of the degradation. At long term, the lifetime of materials is generally limited by this ceiling. At short term glass transition or melting are the limiting properties. The structure-property relationships in this latter field, especially the importance of chain stiffness and crosslinking, are relatively well known.
Concerning elastic properties, the influence of cohesion, cristallinity and -partially- temperature, are relatively well known. In contrast, viscoelastic effects linked to the local motions (β relaxation), are more difficult to predict. The ductility/toughness seems to be sharply linked to the local mobility. However certain aspects, especially the eventual influence of crosslinking, are not yet well understood.
Concerning processing properties, (time-temperature) or (molecular weight-temperature) maps allow to show that all the linear polymers are not thermoplastics. For these latter, processing can be made only in a sharp molecular weight interval. In the case of thermosets, the (temperature-conversion) maps allow to illustrate the main characteristics and to put in evidence the problems linked to the fact that, in the final steps, the thermal degradation interferes with vitrification. Some important aspects of processing, especially damagement linked to differential shrinkages and build-up of morphological heterogeneities are briefly evoked.
© SIRPE 1995
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.