Influence de la modification physique des melanges polymeres sur la morphologie et les proprietes mecanique

In this study data will be presented which shows that the interfacial region of polymer blends can be modified by physical means alone to improve the mechanical properties. This phenomenon is obtained by mixing a crystalline matrix with an amorphous dispersed phase; there is a real contraction at the interface of the matrix on the dispersed phase giving thus the possibility for a good stress transfer between the two phases when the material is submitted to mechanical testing. For the region of low amorphous phase, the modulus shows additive behavior. However, the complementary blend (crystalline polymer in the dispersed phase) showed significant voiding around the dispersed phase and also poor mechanical properties.;The module/composition behavior of some blends show a sinusoidal tendency and is also described by the Kerner model. But other blends did not show this additive behavior. Many systems have been studied and the phenomenon seems to be function of the glass transition of the dispersed phase.;Another approach was studied to improve the interface and the mechanical properties. This one is based on the orientation, at the melting state, of the matrix and the dispersed phase. This type of blend is characterised by an anisotropic behavior which gives generally good properties to the material in the direction of flow. This study showed the possibility to physically modify the interface of polymer blends and to link the morphology to the mechanical properties. (Abstract shortened by UMI.).