Evidence of non-Arrhenius behaviour from laboratory aging and 24-year field aging of polychloroprene rubber materials

Gillen, K.T.; Bernstein, Robert; Derzon, Dora K.

doi:10.1016/j.polymdegradstab.2004.06.010

Cited by 114 publications

(55 citation statements)

References 19 publications

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“…presumably the formation of the starting secondary hydroperoxide or its decomposition. With a mechanism of such complexity, it is not surprising to observe variations of the relative yields, such as CO 2 /O 2 with temperature as found by Gillen et al [6].…”

Section: Introductionmentioning

confidence: 67%

“…As frequently found, the apparent activation energy for global oxidation is higher at high temperature (typically above 80 C) than at low temperature [6,7]. This behaviour has been explained by the fact that termination processes, which are the most dependent on segmental mobility among all the other elementary steps of oxidation radical chains, are less and less efficient when the temperature decreases [8].…”

Section: Introductionmentioning

confidence: 77%

“…Highly sensitive methods for measuring oxygen absorption allowed interesting quantitative results to be obtained: values of the order of 1.3$10 À9 [6] or 3e4 10 À9 mol kg À1 s À1 [7] have been observed at 50 C. The measurements reveal that a steady state is established rapidly after the beginning of exposure. As frequently found, the apparent activation energy for global oxidation is higher at high temperature (typically above 80 C) than at low temperature [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…Gillen et al [6] have also measured the quantity of CO 2 evolved. The ratio CO 2 evolved/O 2 absorbed is of the order of 0.13 at 50 C and 0.3 at 95 C. The presence of CO 2 can result only from secondary processes involving very unstable structures, for instance from a secondary hydroperoxide (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Oxidation of unvulcanized, unstabilized polychloroprene: A kinetic study

Gac

Roux

Verdú

et al. 2014

Polymer Degradation and Stability

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Thermal oxidation in air at atmospheric pressure, in the 80e140 C temperature range and in oxygen at 100 C in the 0.02e3 MPa pressure range, of unvulcanized, unstabilized, unfilled polychloroprene (CR) has been characterized using FTIR and chlorine concentration measurement. The kinetic analysis was focused on double bond consumption. A mechanistic scheme involving unimolecular and bimolecular hydroperoxide decomposition, oxygen addition to alkyl radicals, hydrogen abstraction on allylic methylenes, alkyl and peroxyl additions to double bonds and terminations involving alkyl and peroxy radicals was elaborated. The corresponding rate constants were partly extracted from the literature and partly determined from experimental data using the kinetic model derived from the mechanistic scheme in an inverse approach. Among the specificities of polychloroprene, the following were revealed: The rate of double bond consumption is a hyperbolic function of oxygen pressure that allows a law previously established for the oxidation of saturated substrates to be generalized. CR oxidation is characterized by the absence of an induction period that reveals the instability of hydroperoxides. The kinetic analysis also reveals that peroxyl addition is faster than hydrogen abstraction but slower in CR than in common hydrocarbon polydienes.

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Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Oxidation of unvulcanized, unstabilized polychloroprene: A kinetic study

Gac

Roux

Verdú

et al. 2014

Polymer Degradation and Stability

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show abstract

“…Os autores reforçaram a necessidade de se estabelecer uma extrapolação linear válida e mostraram que determinados mecanismos podem resultar em um comportamento anti-Arrhenius. Outro estudo, usando policloropreno envelhecido em laboratório e 24 anos de em serviço no campo, também mostrou evidências de que a curva de extrapolação linear de Arrhenius não é válida [19] .…”

Section: Introductionunclassified

Estudo do envelhecimento de poliuretanos aplicados na indústria de petróleo

et al. 2010

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Resumo: O Brasil é mundialmente renomado como um líder na extração de petróleo, em águas profundas e ultra profundas. Dentro da cadeia produtiva, grande parte do petróleo e do gás produzido é escoada através de dutos flexíveis que conectam os poços de produção às plataformas. Quando estão apoiadas no fundo do mar, em condição de serviço estático, os dutos flexíveis são denominados flowlines e quando se elevam do fundo do mar até a plataforma, em condição de serviço dinâmico, são denominados risers. Os tubos projetados para aplicações dinâmicas são dotados de bends stiffeners, componentes com formato cônico e, em geral, de base uretânica que têm a função de fornecer uma transição entre a estrutura dos tubos, de rigidez suave, e a plataforma, extremamente rígida. Este trabalho abordou a variação das propriedades mecânicas de poliuretanos como resultado da ação da hidrólise, por envelhecimento acelerado. Os corpos de prova foram expostos a 50, 60 e 70 °C. A variação de massa também foi determinada considerando que esses materiais são projetados para uma vida útil superior a vinte anos. Os poliuretanos apresentaram degradação significativa a 70 °C, o que pode reduzir seu tempo de aplicação no campo por falha mecânica quando submetido a elevadas temperaturas. Palavras-chave: Degradação, poliuretanos, propriedades mecânicas, variação de propriedades. Study of Ageing of Polyurethanes Applied to the Offshore IndustryAbstract: Brazil is worldwide renowned as a leader in oil and gas extraction in deep and ultra deep water. In the production chain, a great part of the oil and gas produced is conveyed through flexible pipelines that connect the production wells to the platforms. When the pipes are laid on the seabed in a static service condition, the flexible pipes are called flowlines and when raised from the seabed to the platform in a dynamic service condition, they are called risers. The pipes designed for dynamic applications are equipped with bend stiffeners, components with conical form and in general based on polyurethanes, which have the function of providing a transition between the structure of the pipes, of smooth stiffness, and the platform, extremely rigid. This work discussed the changes on the mechanical properties of polyurethanes due to hydrolysis under accelerated ageing. The specimens were exposed at 50, 60 and 70 °C. The mass variation was also evaluated considering that these materials are designed for a service life exceeding twenty years. The polyurethanes presented significant degradation at 70 °C, which can reduce its application time in the field owing to mechanical failures when subjected to high temperatures.

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2012

Oxidative Ageing of Polymers

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Evidence of non-Arrhenius behaviour from laboratory aging and 24-year field aging of polychloroprene rubber materials

Cited by 114 publications

References 19 publications

Oxidation of unvulcanized, unstabilized polychloroprene: A kinetic study

Oxidation of unvulcanized, unstabilized polychloroprene: A kinetic study

Estudo do envelhecimento de poliuretanos aplicados na indústria de petróleo

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