Indian Journal of Engineering & Materials Sciences Vol. 15, June 2008, pp. 281-286 Relationship between the electric spark sensitivity and detonation pressure M H Keshavarz Department of Chemistry, Malek-ashtar University of Technology, Shahin-shahr P.O. Box 83145/115, Islamic Republic of Iran Received 23 July 2007; accepted 11 April 2008 A new method for the prediction of electric spark sensitivity of polynitro arenes through maximum obtainable detonation pressure has been proposed. This work uses two additional factors, which depend on the contribution of some structural parameters. Twelve polynitro arenes as training set were applied to optimize new correlation and twenty two polynitro arenes as test set were also used to check the validity of the method. The calculated electric spark sensitivities have a root mean square (rms) deviation of 2.27 J and a maximum deviation of 4.48 J from experimental data for training set. The rms and maximum deviations of predicted electric spark sensitivities from experimental values for test set are 2.28 and 4.77 J, respectively. One of the major goals within the energetic materials community has been to develop capabilities to determine performance and sensitivity of a notional energetic material. However, elimination of any poor candidate due to sensitivity or performance problems through predictive capabilities at early stages of development is highly desirable. Since the development, manufacture, testing and fielding of a new energetic material is so costly in time and money, predicting various properties of new energetic compounds before the expenditure connected with their development and synthesis is very important to chemist and chemical industries. Many kinds of sensitivity have been identified in terms of stimuli causing detonation, which may be included impact, shock, electric spark, heat and friction. The results of impact sensitivity are often not reproducible because the factors in the impact experiment that might affect the formation and growth of hot spots could strongly affect the measurements as well as they are extremely sensitive to the conditions under which the tests are performed. Despite large errors present in some of experimental data, the impact sensitivity has been the most intensively studied 1 . Shock sensitivity is another convenient kind of sensitivity, which can be measured by a standard small or large scale gap test 2 . There are some correlations between shock sensitivity and computed results of quantum mechanical methods or structural parameters 2-6 . The electric spark sensitivity of the high energy compounds is an important quantity to evaluate safety which can be defined as the degree of sensitivity to the electrostatic discharge. In order to seek highly energetic and secure materials, it is important to have appropriate methods in the molecular design of an energetic material. The purpose of this work is to determine a new method for predicting electric spark sensitivity of polynitro arenes by a simple procedure. It will be shown how a general new correlation can be obtained between electric spark sensitivity and maximum obtainable detonation pressure as well as structural parameters of polynitro arenes energetic compounds. To derive a new correlation for electric spark sensitivity, a new procedure for predicting maximum detonation performance was used 7 . One set of experimental data of electric spark sensitivity was used as training set to establish correlation. To test the validity of new correlation, the second set as test set was also used to some polynitro arenes explosives. Electric Spark Sensitivity and Maximum Performance of Explosives Electric spark sensitivity can be expressed as the electrostatic discharge energy required for 50% initiation probability. Its measurements can be carried out with the help of the apparatus and procedures which were described elsewhere 8 . The primary fragmentation reactions in this initiation can be supposed identical with the primary splitting processes of low-temperature thermolysis and detonation transformation of molecules of these _________ E-mail: mhkir@yahoo.com; mhkeshavarz@mut-es.ac.ir