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Combustion Mechanism of Azide Polymer
Author(s) -
Kubota N.,
Sonobe T.
Publication year - 1988
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.19880130604
Subject(s) - propellant , azide , combustion , thermal decomposition , polymer , activation energy , adiabatic flame temperature , materials science , chemistry , decomposition , polymer chemistry , analytical chemistry (journal) , composite material , organic chemistry , combustor
The combustion wave structure and thermal decomposition process of azide polymer were studied to determine the parameters which control the burning rate. The azide polymer studied was glycidyl azide polymer (GAP) which contains energetic – N 3 groups. GAP was cured with hexamethylene diisocyanate (HMDI) and crosslinked with trimethylolpropane (TMP) to formulate GAP propellant. From the experiments, it was found that the burning rate of GAP propellant is significantly high even though the adiabatic flame temperature of GAP propellant is lower than that of conventional solid propellants. The energy released at the burning surface of GAP propellant is caused by the scission of NN 2 bond which produces gaseous N 2 . The heat flux transferred back from the gas phase to the burning surface is very small compared with the heat generated at the burning surface. The activation energy of the decomposition of the burning surface of GAP propellant, E s , is determined to be 87 kJ/mol. The burning rate is represented by r = 9.16 × 10 3 exp(–E s /RT s ) where r (m/s) is burning rate, T s (K) is the burning surface temperature, and R is the universal gas constant. The observed high temperature sensitivity of burning rate is correlated to the relationship of (∂T s /∂T 0 ) p = 0.481 at 5 MPa, where T 0 is the initial propellant temperature.