Insensitive high explosives: VI. experimental determination of the chemical compatibility of nitroguanidine with seven high explosives

Two compatibility test types based on gas generation obtained by vacuum stability test (VST) procedure and on heat generation obtained by heat flow microcalorimetry (HFMC) show that nitroguanidine (NGu), CAS-No. [556-88-7], is compatible with ammonium nitrate (AN), CAS-No. [6484-52-2], ammonium dinitramide (ADN), CAS-No. [140456-78-6], 1,1-diamino-dinitroethylene (FOX-7, DADNE), CAS-No. [145250-81-3], N-guanylurea dinitramide (FOX-12, GUDN, carbamoylguanidinium dinitramide), CAS-No. [217464-38-5], hexogen (RDX), CAS-No. [121-82-4], octogen (HMX), CAS-No. [2691-41-0], and trinitrotoluene (TNT), CAS-No. [118-96-7]. The evaluations with gas generation and heat generation were done using the so-called corresponding reactivity quantities RV and RQ, but the assessment criteria are in accordance with the present NATO standards. NGu and ADN show the rare case of reactivity with a negative assessment quantity, that is their inter-component reactivity quantities show negative values in RV and RQ. The evolved gas volume and the produced heat generation of the 1 : 1 mixture have lower values than the formally calculated values of the mixture. The root cause of this cannot be deduced with mere compatibility testing. A negative assessment quantity RQ is also observed with NGu and TNT at 80 °C, but not at 70 °C.