Thermal degradation in oxygen of polymers with aromatic rings in the chain

Lancaster, J. M.; Wright, William W.

doi:10.1002/app.1967.070110904

Cited by 8 publications

References 3 publications

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Effect of structural variations on the thermo‐oxidative stability of aromatic polyimides

Dine-Hart¹,

Wright²

1972

Makromol. Chem.

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Polyimides were synthesised from a number of diamines and dianhydrides and their stability determined by thermogravimetric analysis a t 4OO0C in air. Wherever possible high molecular weight films obtained by thermal condensation of the polyamic acid intermediates were studied. If this was not possible, films obtained from acetic acid anhydride ciclised polymers or thermally cured powders were used.A well defined order of stability was observed for the polyimides prepared from pyromellitic diauhydride and a variety of diamines. The simplest and most symmetrical struetures had the greatest thermal stability. Lowest stabilities were observed when linking groups were electronegative in nature. ZUSAMMENFASSUNG:Polyimide wurden aus einer Vielfalt van Diaminen und Dianhydriden hergestellt. Ihre Stabilitat bei 400 "C in Luft wurde durch thermogravimetrische Analyse bestimmt. Wenn moglich, wurden hochmolekulare Filme verwendet, die durch thermische Kondensation der Poly-Amidsaure-Zwischenprodukte erhalten wurden. Wenn dies nicht moglich war, wurden Filme aus Polymeren, die mit Acetanhydrid cyclisiert waren, oder warmebehandelte Pulver untersucht. Fur die aus Pyromellithsaure-dianhydrid und einer Vielfalt von Diaminen hergestellten Polyimide wurde eine gut definierte Abstufung der Stabilitat beobachtet. Die einfachsten und symmetrischsten Strukturen besaBen die hochste Warmestabilitat ; die schlechtesten Resultate wurden mit elektronegativen Kopplungsgruppen erzielt.

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Effect of structural variations on the thermo‐oxidative stability of aromatic polyimides

Dine-Hart¹,

Wright²

1972

Makromol. Chem.

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The vacuum and oxidative pyrolysis of poly‐p‐xylylene

Jellinek

Lipovac

1970

J. Polym. Sci. A‐1 Polym. Chem.

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synopsisPoly-p-xylylene prepared by pyrolysis of di-p-xylylene has been degraded under vacuum and in the presence of oxygen as a function of temperature and oxygen pressure. The vacuum pyrolysis is mainly due to "abnormal" structures. Volatiles are initially produced quite slowly, but t>he reaction accelerates subsequently. Arrhenius equations were derived for various ranges of volatile formation. A mechanism has been formulated consisting of random chain scission followed by depropagation (dimers to pentamers); simultaneously another zip reaction produces hydrogen. The thermal, oxidative degradation has been studied above and below the softening point of the polymer as a function of oxygen pressure. A first-order reaction of volatile formation due to "abnormal" chain scission is followed by normal chain scission, which is also first order. The postulated mechanism leads initially to hydroperoxide formation. Arrhenius equations for volatile formation are different below and above the softening point. ' Oxygen consumption also follows a first-order reaction with an energy of activation of 31.5 kcal/mole.

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Polyphenylenes

Noren

Stille

1971

J. Polym. Sci. Macromol. Rev.

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Thermal degradation in oxygen of polymers with aromatic rings in the chain

Cited by 8 publications

References 3 publications

Effect of structural variations on the thermo‐oxidative stability of aromatic polyimides

Effect of structural variations on the thermo‐oxidative stability of aromatic polyimides

The vacuum and oxidative pyrolysis of poly‐p‐xylylene

Polyphenylenes

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