1 B. Roduit (1), P. Guillaume (2), S. Wilker (3), P. Folly (4), A. Sarbach (4), B. Berger (4), J. Mathieu (4), M. Ramin (5), B. Vogelsanger (5) (1) AKTS AG,TECHNOArk 3, 3960 Siders, Switzerland (2) PB Clermont s.a.,Rue de Clermont 176, 4480 Engis, Belgium (3) Bundeswehr Institute for Materials (WIWEB), Grosses Cent, Swisttal-Heimerzheim, Germany (4) armasuisse, Science and Technology, Thun, Switzerland (5) Nitrochemie Wimmis AG, Wimmis, SwitzerlandESTAC August 2010 Rotterdam The Netherlands Estimation of Life Assessment of Energetic Materials using Advanced Kinetic Elaboration of HFC Signals 2 The precise prediction of the degradation of materials TG DSC HFC CL HPLC 3 TG DSC HFC CL HPLC 4 More precise measurement of the thermal aging of energetic materials - Applications of isothermal microcalorimetry (HFC) 5 The precise prediction of the degradation of materials TG DSC HFC CL HPLC 6 TG DSC CL HPLC 7 Experimentally : Just few temperatures 8 reaction progress temperature time predictions? experiments APPLICATION OF HFC 50C < T < 100C T1T1 T2T2 T3T3 days < t < months 0 % < < 5 % The use of HFC enables to gain advanced knowledge on the reaction rate at the early stage of the decomposition 9 7 years ! Reactionrate Reactionprogress Welldefined Welldefined Because baseline is well defined 50C 10 Isoconversional methods Isoconversional methods Uncertainity of thermokinetic analysis : the stages and physico-chemical reaction pathways are generally unknown Observed thermal event can be the sum of thermal events created during certain stages of the reaction which are not always known ? What do you see below? Young women? Old man? Or both? 11 Isoconversional method Reaction rate expressed by the Arrhenius equation Reaction rate at a given reaction progress is only a function of the temperature A( ) and E( ) are the pre-exponential factor and apparent activation energy Isoconversional methods (model free): Three main modifications of isoconversional method are applied in the literature: - Differential (Friedman) - Integral (Flynn-Ozawa-Wall) - Advanced integral based on non-linear procedure (Vyazovkin) Differential isoconversional method = 12 E = 138 kJ/mol Activation energy E as a function of the heat release 13 THERMAL AGING 14 THERMAL AGING 15 STANAG 2895 A2 (Hot dry) Beijing 16 The assumption that the reaction rate da/dt at a given reaction progress is only a function of the temperature (differential isoconversional analysis) is acceptable. It can be applied for a precise life assessment of energetic materials = 17 fast experiments (1 year) Conclusion DSC HFC ? 18 fast experiments (1 year) Conclusion If you want to perform fast experiments (DSC) and get long term predictions using thermokinetics do not expect very precise predictions. If you want to perform fast experiments (DSC) and get very precise predictions using thermokinetics do not expect long term predictions. If you want to achieve long term predictions and expect very precise predictions using thermokinetics do not perform fast experiments (DSC). Do long term isothermal microcalorimetric measurements (HFC) and perform thermokinetics. 19 fast experiments (1 year) Conclusion DSC HFC ? 20 Advanced Kinetics and Technology SolutionsFor more information: Thank you for your attention Acknowledgements Our partners and friends