THERMAL DEGRADATION OF POLYTETRAFLUOROETHYLENE IN FLOWING HELIUM ATMOSPHERE II. PRODUCT DISTRIBUTION AND REACTION MECHANISM

Jun HS; Kim KN; Park KY; Woo SI

Korean Journal of Chemical Engineering, Vol.12, No.2, 183-187, April, 1995

Jun HS, Kim KN, Park KY, Woo SI

The thermal degradation of polytetrafluoroethylene was studied in the helium flowing atmosphere and the temperature range 510-600℃. The products of the thermal degradation of polytetrafluoroethylene were analyzed by an on-line gas chromatograph and the product distribution was obtained. The products consist of tetrafluoroethlene (TFE), perfluoropropene (PFP) and cyclic-perfluorobutane (c-PFB). Under most conditions the main product was TFE. The c-PFB was regarded as the secondary product formed from TFE because the formation of c-PFB strongly depended upon the degradation rate. However, the production of PFP was not related to the degradation rate, but it was influenced by diffusion limitation of gaseous product in the sample matrix. These phenomena were also verified with Curie-point pyrolyser. The results showed that the production of PFP reached a maximum point under diffusion limitation condition. The degradation mechanism of polytetrafluoroethylene was proposed in terms of unzipping mechanism and other mechanism like radical chain transfer reaction.

Keywords:Polytetrafluoroethylene;Thermal Degradation;Product Distribution;Diffusion Effect;DegradationMechanism

[References]

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Goldfarb IJ, McHenry RJ, Penski EC, J. Polym. Sci., 58, 1283 (1962)
Hanford WE, Joyee RM, J. Am. Chem. Soc., 68, 2082 (1946)
Jun HS, Kim KN, Park KY, Woo SI, Korean J. Chem. Eng., 12(2), 156 (1995)
Kim YG, Rhee SW, Polym.(Korea), 4(1), 40 (1980)
Lacher JR, Tompkin GW, Park JD, J. Am. Chem. Soc., 74, 1693 (1952)
Laird RK, Andrews EB, Barrow RF, Trans. Faraday Soc., 46, 803 (1950)
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Madorsky SL, "Thermal Degaradation of Organic Polymers," Interscience, New York (1964)
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Madorsky SL, Straus S, J. Res. Nat'l Bur. Standards, 64A(6), 513 (1960)
Michaelson JD, Wall LA, J. Res. Nat'l Bur. Standards, 58(6), 327 (1957)
Park JD, Benning AF, Downig FB, U.S. Patent, 2,394,581 (1946)
Preses JM, Weston RE, Flynn GW, Chem. Phys. Lett., 46, 69 (1977)
Renfrew MM, Lewis EF, Ind. Eng. Chem., 38(9), 870 (1946)
Siegle JC, Muus LT, Lin TP, Larsen HA, J. Polym. Sci. A: Polym. Chem., 2, 391 (1964)
Simmie JM, Quiring WJ, Tschikow-Roux E, J. Phys. Chem., 73(11), 3830 (1969)
Wall LA, Michaelson JD, J. Res. Nat'l Bur. Standards, 56(1), 27 (1956)
Wall LA, "Fluoropolymers," Wiley-Interscience, New York (1972)
Young EG, Murray WS, J. Am. Chem. Soc., 70, 2814 (1948)

[Referenced By]

[1] Atkinson B, Atkinson VA, J. Chem. Soc., 2086 (1957)

[2] Atkinson B, Trenwith AB, J. Chem. Soc., 2082 (1953)

[3] Buravtsev NN, Grigor'ev AS, Kolbanovskii YA, Kinet. Katal., 26(1), 7 (1985)

[4] Butler JN, J. Am. Chem. Soc., 84(8), 1393 (1962)

[5] Choi SK, Park JD, J. Korean Chem. Soc., 20(2), 141 (1976)

[6] Drennan GA, Matula RA, J. Phys. Chem., 72(10), 3462 (1968)

[7] Errede LA, J. Org. Chem., 27, 3425 (1962)

[8] Florin RE, Parker MS, Wall LA, J. Res. Nat'l Bur. Standards, 70A(2), 115 (1966)

[9] Florin RE, Wall LA, Brown DW, Hymo LA, Michaelson JD, J. Res. Nat'l Bur. Standards, 53, 121 (1954)

[10] Goldfarb IJ, McHenry RJ, Penski EC, J. Polym. Sci., 58, 1283 (1962)

[11] Hanford WE, Joyee RM, J. Am. Chem. Soc., 68, 2082 (1946)

[12] Jun HS, Kim KN, Park KY, Woo SI, Korean J. Chem. Eng., 12(2), 156 (1995)

[13] Kim YG, Rhee SW, Polym.(Korea), 4(1), 40 (1980)

[14] Lacher JR, Tompkin GW, Park JD, J. Am. Chem. Soc., 74, 1693 (1952)

[15] Laird RK, Andrews EB, Barrow RF, Trans. Faraday Soc., 46, 803 (1950)

[16] Lewis EE, U.S. Patent, 2,406,153 (1946)

[17] Lewis EE, Naylor Ma, J. Am. Chem. Soc., 69, 1968 (1947)

[18] Lifshitz A, Carroll HF, Bauer SH, J. Chem. Phys., 39(7), 1661 (1963)

[19] Madorsky SL, "Thermal Degaradation of Organic Polymers," Interscience, New York (1964)

[20] Madorsky SI, Hart VE, Straus S, Sedlak VA, J. Res. Nat'l Bur. Standards, 51, 327 (1953)

[21] Madorsky SL, Straus S, J. Res. Nat'l Bur. Standards, 64A(6), 513 (1960)

[22] Michaelson JD, Wall LA, J. Res. Nat'l Bur. Standards, 58(6), 327 (1957)

[23] Park JD, Benning AF, Downig FB, U.S. Patent, 2,394,581 (1946)

[24] Preses JM, Weston RE, Flynn GW, Chem. Phys. Lett., 46, 69 (1977)

[25] Renfrew MM, Lewis EF, Ind. Eng. Chem., 38(9), 870 (1946)

[26] Siegle JC, Muus LT, Lin TP, Larsen HA, J. Polym. Sci. A: Polym. Chem., 2, 391 (1964)

[27] Simmie JM, Quiring WJ, Tschikow-Roux E, J. Phys. Chem., 73(11), 3830 (1969)

[28] Wall LA, Michaelson JD, J. Res. Nat'l Bur. Standards, 56(1), 27 (1956)

[29] Wall LA, "Fluoropolymers," Wiley-Interscience, New York (1972)

[30] Young EG, Murray WS, J. Am. Chem. Soc., 70, 2814 (1948)