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1

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Evolution of HCN by thermal oxidative degradation from nylon 66 at high temperatures including burning (1980)

Jellinek, H. H. G. ; Dunkle, S.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 1471-1481

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ISSN: 0360-6376

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Work on the evolution of HCN from nylon 66 was extended to temperatures from ca. 300 to 695°C. Below ca. 300°C the evolution of HCN is governed by chemical decomposition, and above 300°C the evolution is controlled by diffusion. Above 530°C oxidation of HCN becomes noticeable and ignition occurs at 590°C. The rate constants for all of the temperature ranges and for the oxidation of HCN are given in terms of Arrhenius equations. The activation energy for the oxidation of HCN before ignition (590°C) is reached is 47 kcal/mole, and beyond this point, the oxidation is controlled by diffusion. The rate constants increase linearly with oxygen concentration as long as HCN oxidation is negligible; however, they pass through maxima if HCN oxidation is appreciable (some HCN is evolved even in the absence of oxygen). A new flash degradation apparatus has been constructed for these high-temperature ranges and a degradation mechanism has been proposed which is in satisfactory agreement with the experimental results.

Additional Material: 11 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pol.1980.170180504

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2

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HCN evolution from thermal and oxidative degradation of poly(diphenyl methane pyromellitimide) at high temperatures (1983)

Jellinek, H. H. G. ; Dunkle, S. R.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 2111-2131

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ISSN: 0360-6376

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: HCN evolution from thermal and oxidative degradation of poly(diphenyl methane pyromellitimide) has been investigated over a range of temperatures from 500 to 1000°C; rate constants and Arrhenius equations have been determined. Kinetics and mechanisms have been proposed and quantitatively evaluated. They account well for the experimental results. The rate determining steps are C—N scission for thermal degradation and H abstraction from the methylene bridge by O2 for oxidative degradation, respectively. At high temperatures, oxidation and thermal decomposition of the evolved HCN take place on its passage through the hot zone of the furnace in the highest range of temperatures (800-1000°C). Additional HCN is produced (〉800°C) from the char obtained during thermal and oxidative degradation.

Additional Material: 22 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pol.1983.170210721

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3

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Kinetcis and mechanism of HCN-evolution from the oxidation of polyurethanes (1983)

Jellinek, H. H. G. ; Dunkle, S. R.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 487-511

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ISSN: 0360-6376

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The oxidative degradation of aliphatic, aromatic, and secondary polyurethanes was investigated over a range of temperatures of 440-1000°C as a function of time and oxygen concentration. The degradation was studied with special emphasis on HCN-evolution; its rate constants and Arrhenius equations were determined. In some of the temperature ranges reactions were diffusion controlled. At relatively low temperatures the oxidative rate constant was a linear function of oxygen concentration, whereas at higher temperatures oxidation of the evolved HCN took place in passage through the hot zone of the furnace; in addition, at these higher temperatures thermal degradation of the polymers and thermal decomposition of HCN in the hot zone occurred simultaneously with oxidation to an appreciable extent. The kinetics and mechanism proposed and quantitatively evaluated account well for the experimental results.

Additional Material: 34 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pol.1983.170210218

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4

Electronic Resource

Evolution of HCN during high-temperature thermal degradation of polyurethanes (1982)

Jellinek, H. H. G. ; Dunkle, S. R.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 2313-2333

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ISSN: 0360-6376

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The thermal degradation of an aliphatic, aromatic, and secondary polyurethane has been studied over a range of temperatures from 500 to 1000°C with respect to the kinetics and mechanism of HCN evolution. This evolution shows a rapid linear increase of evolved HCN with time, passing into a plateau when the polymer has been consumed. In high temperature ranges, thermal decomposition of the evolved HCN also takes place, and in some temperature regions the degradation is diffusion controlled. Overall, the process is governed by a depolycondensation reaction which is the slowest step in a sequence of reactions. The reaction sequence is kinetically evaluated and the respective rate constants, diffusion constants, and energies of activation are presented. The reaction mechanism accounts well for the experimental results in spite of some simplifications which had necessarily to be applied.

Additional Material: 18 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pol.1982.170200833

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5

Electronic Resource

Kinetics and mechanism of HCN evolution from nylon 66 and design of apparatus (1982)

Jellinek, H. H. G. ; Dunkle, S. R.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 85-101

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ISSN: 0360-6376

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The evolution of HCN from the oxidation of nylon 66 has been studied in three apparatuses of different design (all based on stream flow) over a temperature range from 390 to 700°C. Although the numerical values for rate constants (diffusion controlled) and energies of activation differ, the same mechanism is deduced from the results of the three designs. It is concluded that a simple horizontal tube in a furnace is the most efficient apparatus as far as sweeping out volatile products is concerned. The mechanism of thermal oxidative degradation has been evaluated in detail. It is shown that mechanisms where the first reaction step is not the slowest or the slowest one of first or second order all fit the experimental results. However, it is concluded that the mechanism where the first step is first order and the slowest one is the most likely one. The respective parameters have been evaluated for the results obtained from the horizontal tube apparatus.

Additional Material: 18 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pol.1982.170200110

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