Oxidation of polyoxymethylenes

Sukhov, V.A.; Nikitina, L.; Baturina, A. A.; Lukovnikov, A.F.; Yenikolopyan, N.S.

doi:10.1016/0032-3950(69)90316-5

Cited by 7 publications

(4 citation statements)

References 10 publications

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“…As the amorphous phase is permeable to O 2 , its degradation can affect certain use properties, for instance mechanical ones. Hydrolysis is expected only in the presence of acids,2 e.g., in very peculiar used conditions. In contrast, oxidation is expected to be relatively easy, owing to the high reactivity of etheric methylenes to hydrogen abstractions by radicals 3.…”

Section: Introductionmentioning

confidence: 99%

“…It was shown very soon that POM thermal ageing is noticeable accelerated in the presence of oxygen 1. Most of the fundamental published works on POM oxidation mechanisms, originated from two research groups from the former USSR, one was directed by Yenikolopyan and coworkers,2, 4–8 the other by Neiman and coworkers 9–11. Both groups took distinct points of view: the former one considered that the predominant process is depolymerization and that oxygen can play an accelerating role transforming the monomer: formaldehyde, into formic acid, of which the catalytic role on depolymerization is well established.…”

Section: Introductionmentioning

confidence: 99%

“…The Neiman's group considered rather the role of hydroperoxides resulting from the radical chain oxidation. Sukhov et al tried to make a synthesis of both works in 1969 2. What was clearly established is that, thermal ageing of POM at moderate temperatures (typically below 150°C) results essentially from radical chain processes.…”

Section: Introductionmentioning

confidence: 99%

“…The results were somewhat ambiguous: DLTP slows down oxygen uptake but accelerates mass loss (due to depolymerization). The explanation given by the authors2 can be summarized as follows: …”

Section: Introductionmentioning

confidence: 99%

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Thermooxidative ageing of polyoxymethylene, part 1: Chemical aspects

Fayolle

Verdú

Bastard³

et al. 2007

J of Applied Polymer Sci

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The thermal oxidation of unstabilised POM homopolymer has been studied at 90, 110, and 1308C under various oxygen pressures ranging from 0 to 2.0 MPa by gravimetry and IR spectrometry. This latter reveals essentially the formation of formate (F) groups and alcohols in smaller quantities. The formate growth and mass loss rates increase pseudo hyperbolically with oxygen pressure, the asymptotic level being reached at pressures up to 0.5 MPa. These results lead to propose a mechanistic scheme of radical chain oxidation in which depolymerization is initiated by hydroperoxide unimolecular decomposition, one formate and one chain scission being formed per decomposition event whereas the kinetic chain length of the depolymerization zip is of the order of 100. A kinetic model derived from the mechanistic scheme, taking into account substrate consumption, simulates correctly the shape of kinetic curves and the effect of temperature and oxygen pressure.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermooxidative ageing of polyoxymethylene, part 1: Chemical aspects

Fayolle

Verdú

Bastard³

et al. 2007

J of Applied Polymer Sci

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Réactions primaires de dégradation oxydante au cours de l'autoxydation du poly(oxytétraméthylène) à 25°C, 4 Discussion du schéma réactionnel

Thomassin¹,

Marchal²

1977

Makromol. Chem.

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Results from previous publications of the series are interpreted and discussed in terms of a reaction scheme. Probabilities of the different non-terminating reactions of r-alkoxyalkylperoxy radicals during the autoxidation of solutions of poly(oxytetramethylene) lo-' g c m -3 < c 6 6 . 1 0 -2 g were determined as follows: for the H atom abstraction =0,2-0.4, for the monomolecular decomposition (reference)= I , and for the non-terminating bimolecular reaction = 7-10.

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Radiation‐induced oxidation of solid poly(ethylene oxide). II. Mechanism

Decker

1977

J. Polym. Sci. Polym. Chem. Ed.

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The mechanism of γ‐initiated oxidation of solid poly(ethylene oxide) (PEO) has been investigated, and an overall reaction scheme has been developed which accounts for most of the experimental observations. Data are correlated on the basis that the oxidation process is the sum of two reactions that are first‐order and half‐order in rate of initiation. They provide evidence that a significant fraction of the interactions of α‐alkoxyalkylperoxy radicals is nonterminating at ambient temperature and yield free alkoxy radicals that are very subject to β scission. The unimolecular decomposition of secondary peroxy radicals, which has been invoked previously for the oxidation of PEO in solution, is not needed to explain the products of the oxidation of PEO in the solid phase. Approximately 90% of the total oxygen consumption has been accounted for by the observed products of oxidation. The radiochemical yield for backbone radical formation in irradiated PEO was estimated to be 6.5 ± 1.5.

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Oxidation of polyoxymethylenes

Cited by 7 publications

References 10 publications

Thermooxidative ageing of polyoxymethylene, part 1: Chemical aspects

Thermooxidative ageing of polyoxymethylene, part 1: Chemical aspects

Réactions primaires de dégradation oxydante au cours de l'autoxydation du poly(oxytétraméthylène) à 25°C, 4 Discussion du schéma réactionnel

Radiation‐induced oxidation of solid poly(ethylene oxide). II. Mechanism

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