Caractérisation expérimentale d'un élastomère en fonction de la température

L'objectif de ce travail est d'étudier la tenue d'un élastomère fluoro-carboné (FKM) en température. Différents essais mécaniques expérimentaux (traction et compression cyclés et relaxations) ont été réalisés à  des températures allant de -15 à 150°C pour étudier le comportement du matériau

Cristallisation induite sous sollicitations cycliques dans les élastomères

Ce travail constitue une étude exploratoire sur la cristallisation sous contraintes du caoutchouc naturel. Nous avons poursuivi plusieurs objectifs que nous vous avons globalement atteints. En effet, nous avons identifié et validé un protocole mécanique qui permet de générer des cristaux dans ce matériau. Ce protocole est basé sur des sollicitations cycliques effectuées sur une machine DMA-TMA. Nous avons, par là même, mis en évidence l'influence des paramètres de sollicitation sur l'apparition et le cumul de cette cristallisation. Ce changement de structure est prouvé par la température de transition vitreuse (Tg) et par la densité du matériau qui, toutes les deux, augmentent avec la présence des cristaux. Enfin, nous avons vérifié que les cristaux jouent un rôle prépondérant dans la déviation d'une fissure de son trajet initiale de propagation (phénomène « Knotty tearing »)

An asymptotic finite plane deformation analysis of the elastostatic fields at a crack tip in the framework of hyperelastic, isotropic, and nearly incompressible neo-Hookean materials under mode-I loading

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Experimental Validation of the Horikx Theory to be Used in the Rubber Devulcanization Analysis

International audienc

Effects of Clay Nanoparticles on the Mechanical and Physical Properties of Unsaturated Polyester

International audienc

Propriétés mécaniques des nanocomposites Polyamide 12/ montmorillonite”.

International audienc

Mechanical properties of Polyamide-12 layered silicate nanocomposites and their relations with structure

International audienceThe mechanical properties of polyamide-12/Cloisite 30B (PA12/C30B) nanocomposites prepared by melt compounding were studied as a function of clay volume fraction φ under various processing conditions. All measured mechanical characteristics, Young's modulus, yield stress, strain at break and stress at break, exhibit a transition at φp∼1%, identified with a percolation threshold. Also, the linear and non-linear mechanical properties appeared to depend on the degree of exfoliation of the structure, which can be tuned by the processing conditions. The three-phase Ji's theoretical model was used to predict Young's modulus as a function of clay concentration, focusing on the influence of the degree of exfoliation. Experimental yield stress data were fitted to Pukanszky's model and discussed in terms of PA12/C30B interfacial adhesion

Influence of mixing energy on the solid-state behavior and clay fraction threshold of PA12/C30B ® nanocomposites

International audienceAbstract This study focuses on the influence of mixing energy on the solid-state behavior and clay fraction threshold of nanocomposites. Thus, three polyamide12/clay (PA12/C30B ® ) nanocomposites exhibiting different nanostructures were prepared from three sets of processing conditions. Then, thermal and dynamical viscoelastic properties of these nanocomposites were analyzed, in relationship with the material nanostructure and processing conditions. For the first time, the solid-state properties of the nanocomposites revealed the existence of a critical specific mixing mechanical energy. Below this critical value, an increase of mechanical energy refines the structure, improving some end-use properties of the nanocomposite. Above this value, a high mixing energy supply is necessary in order to significantly modify the structure. They also highlighted that the clay fraction threshold, which is commonly attributed to the formation of a three-dimensional percolated network, decreases with increasing specific mixing energy, less significantly when this energy is superior to its critical value

A New Fracture Criterion under Multiaxial Monotonic Loading for Rubbers

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