Thermooxidative and thermohydrolytic aging of composite organic matrices
TypeChapitres d'ouvrages scientifiques
This chapter deals with the main causes of chemical ageing in organic matrix composites: hydrolysis, essentially in polyesters and polyamides, and oxidation in all kinds of polymer matrices. The first section is devoted to common aspects of chemical degradation of organic matrices. It is shown that chain scission and, at a lesser extent, crosslinking are especially important because they induce embrittlement at low conversions. Quantitative relationships between structural parameters and mechanical properties are briefly examined. The second section deals with diffusion-reaction coupling. In the cases of hydrolysis and oxidation, kinetics can be limited by respectively water and oxygen diffusion. Then, degradation is confined in a superficial layer, that can carry important consequences on use properties. The third section is devoted to hydrolysis. The kinetic equations are presented in both cases of non equilibrated and equilibrated hydrolysis. Structure-stability relationships are briefly examined. Osmotic cracking process, very important in the case of glass fiber/unsaturated polyester composites, is described. The last section is devoted to thermal oxidation. The simplest kinetic models are presented. The main gravimetric behaviours are explained. A mechanism is proposed for the "spontaneous cracking" in the superficial layer of oxidized samples.
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Thermo-oxidation behaviour of composite materials at high temperatures: A review of research activities carried out within the COMEDI program LAFARIE, Marie Christine; GRANDIDIER, Jean Claude; OLIVIER, Loic; COLIN, Xavier; VERDU, Jacques; CINQUIN, Jacques (Elsevier, 2010)The present paper presents a review of the main activities carried out within the context of the COMEDI research program, a joint collaboration involving three research teams focusing on the thermo-oxidation behaviour of ...
RICHAUD, Emmanuel; AUDOUIN, Ludmila; COLIN, Xavier; FAYOLLE, BRUNO; VERDU, Jacques (In Tech, 2012)Polymers having an aromatic backbone polymers have a high mechanical strength and a high modulus. Their aromaticity increases their resistance for use in relatively severe conditions especially in aerospace and nuclear ...
RICHAUD, Emmanuel; COLIN, Xavier; MONCHY-LEROY, Carole; AUDOUIN, Ludmila; VERDU, Jacques (Society of Chemical Industry, 2011)The radiochemical degradation of bisphenol A polysulfone was investigated under a γ-ray dose rate of 24 kGy h-1 up to 30.7 MGy total absorbed dose at 60 °C using gel permeation chromatography, sol-gel analysis, glass ...
AUDOUIN, Ludmila; COLIN, Xavier; FAYOLLE, Bruno; RICHAUD, Emmanuel; VERDU, Jacques (EDP Sciences, 2010)It has been supposed, for a long time, that kinetic modelling of polymer ageing for nonempirical lifetime prediction was out of reach for two main reasons: hypercomplexity of mechanisms and heterogeneity of reactions. The ...
Stabilizer thickness profiles in polyethylene pipes transporting drinking water disinfected by bleach COLIN, Xavier; VERDU, Jacques; RABAUD, Benjamin (Society of Plastics Engineers, 2011)Polyethylene connection pipes of wall thickness ranging from 3.0 to 4.5 mm, used for 0, 5, 9, 12, and 18 years in the French network of drinking water disinfected by bleach, have been analyzed. The stabilizer thickness ...