Degradation kinetics of polytetrafluoroethylene and poly(ethylene-alt-tetrafluoroethylene)

Abstract

This article studies the degradation kinetics of two fluorocarbon-based polymers, polytetrafluoroethylene (PTFE) and poly(ethylene-alt-tetrafluoroethylene) (ETFE), that are commonly used in coatings, solid lubricants and wiring insulation. During the onset of degradation, these polymers may fail in their desired function, with associated monetary or human cost. This work examines the degradation kinetics of PTFE and ETFE by applying thermogravimetric analysis. Results from an isoconversional method, where activation energy is represented as a function of the extent of degradation, are used to develop kinetic models describing their degradation. A statistical analysis to evaluate the accuracy and validity of the implemented kinetic models is presented and it is found that an nth-order, single-step autocatalytic reaction model best describes the degradation of PTFE, whereas a consecutive three-step autocatalytic reaction model best describes the degradation of ETFE.

Keywords

Fluoropolymers ETFE (Tefzel®)PTFE (Teflon®)degradation kinetics isoconversional thermogravimetry

Get full access to this article

View all access options for this article.

References

Furse

Haupt

. Down to the wire. IEEE Spectrum 2001; 38: 34–39.

Dupont

Safety of teflon non-sticks, http://www2.dupont.com/Teflon/en_US/products/safety/key_questions.html# (accessed 14 September 2011).

Blumm

Lindemann

Meyer

Strasser

. Characterization of PTFE using advanced thermal analysis technique. Int J Thermophys 2010; 31: 1919–1927.

Baker

Jr Kasprzak

. Thermal degradation of commercial fluoropolymers in air. Polym Degrad Stabil 1993; 42: 181–188.

Prasad

Singh

. Thermal decomposition kinetics of a commercial fluoropolymer. Mater Res Bull 1995; 30: 1407–1412.

Schild

. Application of TGA/FTIR to the thermal degradation mechanism of tetrafluoroethylene–propylene copolymers. J Polym Sci: A 1993; 31: 1629–1632.

Hammoud

Stavnes

Suthar

Laghari

. Effects of Thermal and Electrical Stressing on the Behavior of Space Wiring. IEEE Conference on Electrical Insulation and Dielectric Phenomena, 1995, pp. 266–269.

Levi

Reich

Lee

. Degradation of polymers by thermal gravimetric techniques. Polym Eng Sci 1965; 5(3): 135–141.

Brown

Dollimore

Galewey

AK.

Reactions in the solid state, comprehensive chemical kinetics. Vol. 22. Amsterdam, The Netherlands: Elsevier.

10.

Vyazovkin

. Kinetic concepts of thermally stimulated reactions in solids: a view from a historical perspective. Int Rev Phys Chem 2000; 19(1): 45–60.

11.

Friedman

. Kinetics of thermal degradation of char-forming plastics from thermogravimetry. J Polym Sci C: Polym Sympos 1964; 6(1): 183–195.

12.

Ozawa

. A new method of analyzing thermogravimetric data. Bull Chem Soc Jpn 1965; 38(11): 1881–1886.

13.

Flynn

Wall

. General treatment of the thermogravimetry of polymers. J Res Natl Bur Stand 1966; 70a(6): 487–523.

14.

Opfermann

Kaisersberger

. An advantageous variant of the Ozawa–Flynn–Wall analysis. Thermochim Acta 1992; 203: 167–175.

15.

Hondred

Yoon

Bowler

Moukhina

Kessler

High Perform Polym 2011; 23(4): 335–342.

16.

Netzsch Thermokinetics (v. 2004.05) (Program help), 2004.