Mechanisms of antiozonant protection of elastomers

Lake, G. J.; Mente, Pumza

doi:10.1016/0141-3910(95)00070-3

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…The resulting nitroxyl radicals may undergo additional irreversible oxidation with ozone leading to many other products. [2,4,5,[10][11][12]24,[28][29][30] However, in real condition, an excess of ozone never can be reached. Consequently, the nitroxyl radicals produced by ozonation may play a role inside a rubber matrix exerting both an antioxidant and mainly an antifatigue activity, exactly as in the case of the nitroxyl radicals formed by the antioxidant action of secondary aromatic amines.…”

Section: Discussionmentioning

confidence: 99%

“…Natural rubber and synthetic diene rubber (polyisoprene, polybutadiene, styrene-butadiene copolymer, other butadiene copolymers) are very sensitive to ozone attack which causes the formation of cracks on the surface of rubber articles and may lead to the failure of the said articles. The subject of ozone attack, degradation, and protection of tires and rubber-made technical articles has been reviewed very clearly in numerous works, for example, in References [1][2][3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

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Aminoxyl (nitroxyl or nitroxide) radical formation by the action of ozone on squalene containing secondary aromatic amine antioxidants

Cataldo

2021

Vinyl Additive Technology

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Squalene, a model compound of polyisoprene or natural rubber, was employed as solvent to study the reaction between ozone and a series of N,N′‐substituted‐p‐phenylenediamines (PPDs) and other secondary aromatic amines. In all cases, it was found that nitroxyl radicals were formed nearly quantitatively by the action of ozone on the squalene solutions containing dissolved the selected additives. The resulting nitroxyl radicals from PPDs or from other secondary aromatic amines were easily detected by electron spin resonance spectroscopy at room temperature and the isotropic and anisotropic hyperfine interaction constants of the said nitroxides were determined. The FT‐IR spectroscopy was employed to show the easy oxidation of unprotected squalene when exposed to an ozone stream, while in presence of PPDs, ozone is quantitatively scavenged by the PPDs forming the resulting nitroxides and protecting completely squalene from ozonolysis reactions. The nitroxyl radicals formed by PPDs or secondary aromatic amine ozonation exert a permanent antioxidant activity entering in a redox cycle already known to ensure a long flex fatigue life or the given rubber compound.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aminoxyl (nitroxyl or nitroxide) radical formation by the action of ozone on squalene containing secondary aromatic amine antioxidants

Cataldo

2021

Vinyl Additive Technology

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“…Moreover, the presence of this highly oxidizing gas within the hollow insulator was thought to be responsible for the corrosion observed on the metallic parts. It was also thought to induce the mechanical breaking of the nitrile piston seal, known for poor ozone resistance [36][37][38].…”

Section: Failure Mechanismsmentioning

confidence: 99%

Effects of electric partial discharges on the rheological and chemical properties of polymers used in HV composite insulators after railway service

Habas

Arrouy

Perrot³

2009

IEEE Trans. Dielect. Electr. Insul.

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The origin and the consequences of the electric failure of in-service composite hollow insulators used in railway transportation were investigated. Direct electrical measurements made it possible the detection of partial discharges (PD) and UV emissions allowed of identifying the location of the PD at the interface between metal braids and a silicone liner. To investigate the effects of the damaging PD activity, physicochemical properties of the different polymers were investigated and compared to new samples. The thermomechanical properties of the HTV and RTV silicones showed important alterations in the polymers structure. The chemical analyses of the silicones and nitrile rubber conducted using ATR-FTIR spectroscopy revealed that the polymers were oxidized after electrical failure. The results indicated that the ozone production and UV emission were due to the surface electrical activities. The breakdown of alumina trihydrate (ATH) in the inner HTV silicone liner demonstrated that undesired electrical discharges induced an significant increase of temperature and the formation of moisture in the air present in the hollow insulator. Laboratory artificial aging performed on the silicones and nitrile rubber showed similar degradation as in service. Further electrical experiments conducted on empty hollow insulators enabled the detection of internal PD located in micro-voids present in the adhesive used to bond the HTV silicone liner to the inner composite tube.

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“…Hence, such experiments usually employ very high ozone concentrations, e.g. 10 5 ppb, far above normal ambient levels of 10-100 ppb [11,12]. There have been some attempts to use the cracking behavior of rubber as a measure of ozone concentration.…”

Section: Introductionmentioning

confidence: 99%

Elastomeric ozone concentration detector

Mott

Roland

2001

Materials Science and Engineering: A

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Micron-sized surface cracks develop in polybutadiene when stretched and exposed to ozone. The consequent reduction in the transparency of the rubber provides a method for quantifying the ambient ozone concentration. The rate at which opacity develops depends linearly on the amount of ozone, and increases with increasing strain. This method of detecting atmospheric ozone has high sensitivity (1 ppb) and a broad dynamic range. The crack morphology can be interpreted in terms of nucleation and growth.

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Mechanisms of antiozonant protection of elastomers

Cited by 12 publications

References 8 publications

Aminoxyl (nitroxyl or nitroxide) radical formation by the action of ozone on squalene containing secondary aromatic amine antioxidants

Aminoxyl (nitroxyl or nitroxide) radical formation by the action of ozone on squalene containing secondary aromatic amine antioxidants

Effects of electric partial discharges on the rheological and chemical properties of polymers used in HV composite insulators after railway service

Elastomeric ozone concentration detector

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