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| Richaud, Emmanuel; Le Gac, Pierre-yves; Verdu, Jacques. |
| Thermal ageing of thin films of unstabilized polydicyclopentadiene (pDCPD) at several temperatures ranging from 120 to 30°C was investigated by means of carbonyl build up by FTIR with ammonia derivatization, double bond titration, mass uptake measurement, hydroperoxides titration by iodometry and DSC coupled with sulfur dioxide treatment. In the temperature range under investigation, pDCPD is in glassy state and it oxidizes faster than common polymers oxidized at rubbery state (e.g. polydienic elastomers). Using the kinetic analysis, these results were ascribed to increased initiation rate due to catalyst residues, some possible intramolecular processes favoring propagation, or a very low termination rate of oxidation radical chains because of the control... |
| Tipo: Text |
Palavras-chave: Polydicyclopentadiene; Thermal oxidation; Kinetics; Molecular mobility. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00175/28646/27073.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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| Defauchy, Virginie; Le Gac, Pierre-yves; Guinault, Alain; Verdu, Jacques; Recher, Gilles; Drozdzak, Renata; Richaud, Emmanuel. |
| The in situ thermal oxidation of thin unstabilized polydicyclopentadiene was studied by TGA to monitor mass gain, and DSC to characterize hydroperoxides concentration. Results were discussed using kinetic analysis, which allowed the estimation of activation energies for key reactions of the oxidation process. Activation energy for termination was shown to be higher than in hydrocarbon liquids, which was discussed from the theory of diffusion controlled reactions, and a possible link with local motions associated with sub-glassy transition. Activation energy of thermal decomposition of hydroperoxides was found lower than for model hydroperoxides, suggesting an accelerating effect of organometallic catalysts. Despite those two results that indicate a poor... |
| Tipo: Text |
Palavras-chave: Polydicyclopentadiene; Thermal oxidation; Segmental mobility; Catalysis; Diffusion limited oxidation. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00388/49904/50476.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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