Study of Thermal Decomposition Products of Silica-Filled Polytetrafluoroethylene with an Infrared Pyrolysis Cell

Abstract

An infrared pyrolysis cell has been developed which permits thermal decomposition of microsamples in the beam of an infrared spectrophotometer. Organic and inorganic materials may be degraded at controlled temperatures up to 1100°C in oxidizing, inert, or vacuum atmospheres The system silica-polytetrafluoroethylene (PTFE, Teflon) was studied in the temperature range 500 to 600°C in air and in helium. When heated in air, mixtures containing up to 23 per cent silica were totally volatilized, but in an inert atmosphere only the PTFE is volatilized without loss of significant quantity of silica. The principal species observed following the air pyrolysis of silica-PTFE composite were S₁F₄, COF₂, and CO₂; the same material pyrolised in helium resulted in the identical products as unfilled PTFE, namely, C₂F, C_3F and C₄F₈ The probable equation for the interaction between PTFE and silica in air is (– C₂F₄ –)_n + S₁O₂ + 2O₂ → 2COF₂ + S₁F₄ + 2CO₂ + C₂F₄ + C₂V₄ recombination products

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References

Atkinson

and Atkinson

V. A.

, J. Chem. Soc. (London), 2082 (1957)

Brash

M. P.

Burrell

B. W.

and Perkins

J. S.

, APPLIED SPECTROSCOPY, 17, 125 (1963)

Butler

J. N.

, J. Am. Chem. Soc., 84, 1393 (1962)

Claassen

H. H.

, J. Chem. Phys., 18, 543 (1950)

Edgell

W. F.

, J. Am. Chem. Soc., 70, 2816 (1948)

Eggers

D. F.

Jr. and Crawford

B. L.

Jr. , J. Chem. Phys., 19, 1554 (1951)

Gray

B. F.

and Pritchard

H. O.

, J. Chem. Soc. (London), 1002 (1956)

Heicklen

and Knight

, Spectrochimica Acta, 20, 295–8 (1964)

Hudlicky

, Chemistry of Organic Fluorine Compounds, The Macmillan Co., New York, N. Y., 1959, pp. 275–6

10.

Kline

G. M.

, Analytical Chemistry of High Polymers Part I, Interscience Publishers, Inc., New York, N. Y., 1959, pp. 186–7

11.

Kupel

R. E.

Noland

Keenan

R. G.

Hite

, and Scheel

L. D.

, Anal. Chem. 36, 386–9 (1964)

12.

Jones

E. A.

Kirby-Smith

J. S.

Woltz

P. J. H.

and Neilsen

A. H.

, J. Chem. Phys., 19, 242 (1951)

13.

Lewis

E. S.

and Naylor

M. A.

, J. Am. Chem. Soc., 69, 1968 (1947)

14.

Light

T. S.

Fitzpatrick

L. F.

and Phaneuf

J. P.

, Anal. Chem., 37, 79–82 (1965)

15.

Madorsky

S. L.

, SPE Journal, 18, 1–9 (1962)

16.

Madorsky

S. L.

Hart

V. E.

Straus

and Sedlak

V. A.

, J. Research Nat'l. Bur. Standards, 51, 237 (1953)

17.

Madorsky

S. L.

and Straus

, Ibid, 55, 223 (1955)

18.

Madorsky

S. L.

and Straus

, Ibid, 64A, 513 (1960)

19.

Madorsky

S. L.

and Straus

, The Society of Chemical Industry Monograph, No. 13, 60 (1961)

20.

Madorsky

S. L.

and Straus

, Simposio Inter-nazionale di Chimica Macromolecolare, Supplemento a La Ricerca Scientifica (1955)

21.

Miller

F. A.

and Wilkins

C. H.

, Anal. Chem., 24, 1253 (1952)

22.

Neilsen

A. H.

Burke

T. G.

Woltz

P. J. H.

and Jones

E. A.

, J. Chem. Phys., 20, 596 (1952)

23.

Neilsen

A. H.

and Claassen

H. H.

, Ibid, 18, 812 (1950)

24.

Stone

R. L.

, Anal. Chem., 32, 1582 (1960)

25.

Wall

L. A.

and Michaelson

J. D.

, J. Research Nat'l. Bur. Standards, 56, 27 (1956)

26.

Wall

L. A.

and Straus

, Ibid, 65A, 227 (1961)

27.

White

Jr. , and Rice

O. K.

, J. Am. Chem. Soc., 69, 267 (1947)