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| Richaud, Emmanuel; Huang, Jing; Le Gac, Pierre Yves. |
| This paper addresses the lifetime prediction of polydicyclopentadiene submitted to thermal oxidation, using a multiscale approach. The chemical changes monitored by FTIR revealed the depletion in double bonds and the appearance of carbonyls. Such molecular changes result in the drop of mechanical properties. A kinetic model was implemented to predict the degradation rate depending on external conditions (temperature, oxygen concentration). This model can be completed to take into account the effect of antioxidants (delaying the thermal degradation) and the oxygen diffusion effects (heterogenous degradation) so as to get closer of real cases. |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00644/75621/76539.pdf |
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| Huang, Jing; Derue, Isabelle; Le Gac, Pierre Yves; Richaud, Emmanuel. |
| This paper describes water absorption in polydicyclopentadiene (PDCPD) and more specially the impact of thermal oxidation on its behavior. Unaged PDCPD is found to be almost hydrophobic consistently with its non-polar structure. During thermal oxidation, hydrophilicity progressively increases with ageing time. This increase is linked with the buildup of polar products (mainly ketones, carboxylic acids, hydroperoxides, alcohols). Moreover, it appears that water absorption in PDCPD obeys to Flory Huggins law for all conditions considered here. In the meantime, water diffusivity seems to decrease when oxidation level increases. Finally, a mastercurve that links carbonyl concentration, water diffusivity and water-polymer interaction parameter is proposed and... |
| Tipo: Text |
Palavras-chave: Polydicycopentadiene; Water absorption; Thermal oxidation. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00633/74466/74293.pdf |
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| Huang, Jing; Minne, Wendy; Drozdzak, Renata; Recher, Gilles; Le Gac, Pierre Yves; Richaud, Emmanuel. |
| Thin unstabilized PDCPD film were thermally oxidized in ovens at several temperatures ranging from 50 °C to 120 °C. Hydroperoxide concentration was monitored by DSC. It was observed that hydroperoxides concentration reaches a plateau with short induction times, for example around 8 h at 50 °C. This plateau occurs at very high concentration, around about 1 mol l−1 at 50 °C. In order to study both the chemical mechanisms and the kinetics of hydroperoxides decomposition, oxidized samples were thermally aged in an inert atmosphere to destroy hydroperoxides. For initially high concentrations corresponding to the “plateau”, it was shown that hydroperoxides decompose following a bimolecular process, the rate constant of which being calculated from the... |
| Tipo: Text |
Palavras-chave: Polydicyclopentadiene; Thermal oxidation; Hydroperoxide decomposition; Polymerization catalysts. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72080/70798.pdf |
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