Peroxide cross-linking of EPDMs having high fractions of ethylenic units
TypeArticles dans des revues avec comité de lecture
The considerable amount of research in the literature has practically allowed the elucidation of the mechanism of peroxide cross-linking of ethylene–propylene–diene–monomer rubber (EPDM), which occurs through a radical chain reaction initiated by the thermal decomposition of the peroxide molecule. According to this radical chain reaction, all types of labile hydrocarbon bonds (i.e., allylic, methynic, and methylenic CH bonds) would be exposed to alkoxy radicals and involved in the formation of the elastomeric network. However, for high fractions of ethylenic units (typically ≥60 mol.%), simple chemical kinetics and thermochemical analyses have shown that the radical attack would essentially occur on the methylenic CH bonds. Starting from this assertion, a simplified mechanistic scheme has been proposed for the three commercial EPDMs under study. The corresponding kinetic model, derived from this new scheme by using the basic concepts of the chemical kinetics, provides access to the changes in concentration of the main reactive chemical functions (against exposure time), among which are double bonds and changes in cross-linking density. The validity of these predictions has been eventually successfully verified by five distinct analytical techniques frequently used for studying the cross-linking of rubbers.
Showing items related by title, author, creator and subject.
Time to failure prediction in rubber components subjected to thermal ageing: A combined approach based upon the intrinsic defect concept and the fracture mechanics BEN HASSINE, Mouna; NAÏT-ABDELAZIZ, M; ZAÏRI, F; COLIN, Xavier; TOURCHER, C; MARQUE, Gregory (Elsevier, 2014)In this contribution, we attempt to derive a tool allowing the prediction of the stretch ratioat failure in rubber components subjected to thermal ageing. To achieve this goal, the mainidea is to combine the fracture ...
RICHAUD, Emmanuel; FERREIRA, Paulo; AUDOUIN, Ludmila; COLIN, Xavier; VERDU, Jacques; MONCHY-LEROY, Carole (Elsevier Ltd., 2010)Thin (60 μm) and thick (250 μm) samples of poly(ether ether ketone) were subjected to radiochemical ageing at 24 kGy h -1 dose rate for doses up to 30.7 MGy at 60 °C in air. FTIR spectrophotometry (hydroxyl and carbonyl ...
SERROR, Maéva; COLIN, Xavier; LARCHE, Jean-François (LAVOISIER, 2013)Le vieillissement thermique d’un jonc composite carbone/époxy a été étudié dans l’air entre 160 et 220 °C par tomographie X, microscopie optique et flexion trois points. La thermo-oxydation de la matrice affecte une couche ...
SCHMIDT, Colin; MANGA, Xavier (2013)La mise en scène des produits et des marques placés : représentations, significations publics.
EL MAZRY, Chaker; BEN HASSINE, Mouna; CORREC, Olivier; COLIN, Xavier (ELSEVIER, 2013)Thermal aging of an additive free PA 6-6 has been elucidated at 90, 100, 120, 140, 150 and 160 C in airventiled ovens by Fourier transform infrared spectrophotometry, viscosimetry in molten state and uniaxial tensile ...