New findings on thermal degradation properties of fluoropolymers
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In this paper, the thermal degradation properties of Viton A and Fluorel are investigated by both isoconversional and combined kinetic analysis methods using non-isothermal thermogravimetry technique. It has been found that the heating rate has little affect on the degradation residue of Fluorel and Viton A, where around 1.3% char was formed for Fluorel and 3.5% for Viton A. Different from the literature, the decomposition of Viton A should be considered as an overlapped dehydrofluorination and carbon chain scission process, with activation energy of 214 ± 11 and 268 ± 13 kJ mol−1, respectively. The effect of dehydrofluorination on degradation of Fluorel is not so significant due to low content of H, and hence, it could be considered as a single-step mechanism with average activation energy of 264 ± 14 kJ mol−1. The thermal stability of Fluorel is much better than that of Viton A, and the predicted half-life is around 218 min for Fluorel and 49 min for Viton A at 420 °C, which are consistent with experimental values. If using a single-step model as in the literature for Viton A, its half-life at 420 °C would be underestimated for >20%.
KeywordsThermal decomposition Constant rate Fluoropolymer Reaction models Half-life
The authors would like to present special thanks to ERASMUS (2013–2014) program for the financial support on cooperation between University of Pardubice in Czech Republic and University of Sevilla in Spain. Valuable discussion on kinetic prediction with Dr. P. E. Sánchez Jiménez from Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla is also greatly appreciated.
- 1.Nouguez B, Mahé B, Vignaud PO. Cast PBX related technologies for IM shells and warheads. Sci Tech Energ Mater. 2009;70(5–6):135–9.Google Scholar
- 11.Zeman S, Elbeih A, Akstein Z. Preliminary study on several plastic bonded explosives based on cyclic nitramines. Chin J Energ Mater. 2011;19(1):8–12.Google Scholar
- 12.Elbeih A, Pachmán J, Zeman S, Trzcinski AW, Akstein Z, Muhamed S. Thermal stability and detonation characteristics of pressed and elastic explosives on the basis of selected cyclic nitramines. Cent Eur J Energ Mater. 2010;7(3):217–32.Google Scholar
- 23.David C. In: Bamford CH, Tipper CFH, editors. EBST comprehensive chemical kinetics, vol. 14. Amsterdam: Elsevier; 1977. p. 1–173.Google Scholar
- 24.Wright WW. In: Robb JC, Peaker FW, editors. Progress in high polymers, vol. 2. London: Heywood; 1968. p. 193.Google Scholar
- 26.Madorsky SL. Thermal degradation of organic polymers. New York: Interscience; 1964.Google Scholar
- 27.Perez-Maqueda LA, Criado JM, Sanchez-Jimenez PE. Combined kinetic analysis of solid-state reactions: a powerful tool for the simultaneous determination of kinetic parameters and the kinetic model without previous assumptions on the reaction mechanism. J Phys Chem A. 2006;110(45):12456–62.CrossRefGoogle Scholar
- 32.Wall LA. Fluoropolymers. New York: Wiley Interscience; 1972.Google Scholar