Advances in science and technology of modern energetic materials: an overview.

Ammonium nitrate: a promising rocket propellant oxidizer

https://imechanica.org/files/catastrophic_debonding.pdf

The Mori–Tanaka method for composite materials with nonlinear interface debonding

This volume brings together international scientists in the field of solid rocket propulsion. Thirty-nine papers present in-depth coverage on a wide range of topics including: advanced materials and non-traditional formulations; the chemical aspects of organic and inorganic components in relation to decomposition mechanisms, kinetics, combustion and modelling; safety issues, hazards and explosive characteristics; and experimental and computational interior ballistics research, including chemical information and the physics of the complex flow field.

Solid propellant chemistry, combustion, and motor interior ballistics

https://www.yang.gatech.edu/publications/Journal/PECS%20(Beckstead,%202007).pdf

Modeling of combustion and ignition of solid-propellant ingredients

The compositions and microstructures, thermolyses, and sensitivities of 3,3-bis(azidomethyl)oxetane (BAMO) copolymers with 3-nitratomethyl-3-methyloxetane (NMMO) were characterized. The molar ratios of monomers fed in the copolymerizations were: BAMO/NMMO = 8/2, 7/3, and 6/4. The observed compositions were 81/19, 68/32, and 60/40, respectively. The relative compositions of trade microstructures were also exactly the same as theoretical values. The copolymerization of BAMO with NMMO behaved like an ideal system in the sense that the copolymer has approximately the same composition as the monomer fed. The microstructures of copolymers were also randomly arranged. Poly BAMO showed side chain decomposition in the initial stage of the thermolysis, on the other hand, backbone decomposition controlled the thermolysis of poly NMMO. The BAMO units and the NMMO units appeared to decompose more or less independently of one another and retained their individual decomposition characteristics despite being copolymerized. However, the heat generated by the NMMO decomposition, which occurred at 40°C lower than that of BAMO. activated the reaction of BAMO. Poly B/N(7/3) showed very interesting characteristics in sensitivities, mechanical properties, and the heat of decomposition.

Characterization of BAMO/NMMO Copolymers

On a etudie la sensibilite au choc balistique et la vitesse de combustion de propergols composites GAP/AN. Les esters nitriques, p. ex. TMETN et NC, etaient des modificateurs balistiques tres efficaces, qui ont donne des vitesses de combustion et des exposants de pression utiles pour des propergols a base de AN a faible signature. Leurs proprietes mecaniques a basse temperature sont devenues moins sensibles a la temperature en ajoutant des esters nitriques. Les propergols plastifies par du dioctyladipate ont montre d'excellentes proprietes mecaniques dans le domaine de temperature operationnel. Le mecanisme d'initiation primaire du Card-Gap-Test n'a pas ete influence par les proprietes mecaniques. Bien que la NC ait considerablement augmente la pression critique de choc, 14,8% d'octogene et l'AP ont moins d'effet sur la sensibilite. Les propergols GAP/AN ont donne d'excellentes proprietes d'insensibilite aux chocs balistiques appliques ici.

Insensitive munitions (IM) and combustion characteristics of GAP/AN composite propellants

The effects of copolymerization of THF, as an inert component, AMMO, as an energetic one and NMMO, as a nitrate ester, with BAMO on their thermal decomposition are reported here. Although the thermal decomposition of the BAMO and NMMO units in B/N(7/3) carry out independently and the heat generated by the NMMO unit decomposition accelerates the BAMO unit decomposition, the THF and AMMO units do not affect that of the BAMO unit in B/T(7/3) and B/A(7/3). One exothermic peak in DSC is shown for B/A(7/3) and B/T(7/3) except for B/N(7/3) which shows two peaks. One peak at lower temperature is from the NMMO unit decomposition and the other is from the BAMO unit. The rate of decomposition of B/A(7/3) is the same as that of poly(BAMO), which indicates that the reactivity of the AMMO unit is equal to that of the BAMO unit.

In propellant, containing 75% HMX and 25% copolymer binder, burning rate of B/A(7/3)/HMX is faster than that of B/N(7/3)/HMX. Although the heat of decomposition for B/A(7/3) in DSC is smaller than that for B/N(7/3), that of B/A(7/3)/HMX is larger than that of B/N(7/3)/HMX. The reaction occurred in the condensed phase of the propellant, therefore, may play an important role in the combustion.

Thermal decomposition of BAMO copolymers

En vue d'ameliorer les proprietes mecaniques dans le domaine des basses temperatures, on a synthetise un copolymere de composition 3,3-bis(azidomethyl)oxetane (BAMO), 3-nitratomethyl-3-methyloxetane (NMMO) et polyester (PE), en utilisant un initiateur polyester avec de l'etherate de trifluorure de bore. Le rapport moleculaire de chaque unite du copolymere BAMO/NMMO/PE etait 7,4/2,6/0,39 d'apres l'analyse 1 H-RMN et c'etait a peu pres exactement la meme composition que celle du composant monomere (7/3/0,33). La composition relative des microstructures des triades etait identique a la valeur theorique et elles etaient reparties arbitrairement. Le PE a ete utilise pour remplacer le 1,4-butanediol et a agi comme un excellent plastifiant dans le copolymere; la temperature de transition vitreuse de l'elastomere a ete reduite de 4,8 degres par ce remplacement. Cet effet a egalement ete verifie dans les proprietes mecaniques du propergol composite et l'elongation de traction a ete augmentee de 15% a 40% a -40 °C.

BAMO/NMMO copolymer with polyester initiation

On a etudie trois rapports differents lors de la copolymerisation des copolymeres BAMO/NMMO, non seulement dans la perspective de l'impulsion specifique elevee souhaitee pour les propergols HMX, mais egalement pour leur aptitude a etre utilises en tant que munition insensible. Le rapport molaire de BAMO sur NMMO etait 8/2, 7/3 et 6/4. Bien que la chaleur mesuree au moyen de la DSC ait ete la plus grande en valeur relative pour le propergol B/N (7/3), il n'y a pas eu de differences en ce qui concerne les caracteristiques de decomposition. La reaction exotherme du liant azide et du HMX a eu lieu dans la meme gamme de temperature. La vitesse de combustion superieure a ete preservee avec une proportion de BAMO superieure dans le liant. La sensibilite au choc etait la plus faible pour le propergol HMX B/N (7/3). Il se peut que cette stabilite inattendue ait ete causee par l'effet physique de la structure moleculaire du B/N (7/3), qui peut contribuer a une attenuation inattendue de l'effet de choc. Bien que la vitesse de detonation ait augmente de la meme maniere que la vitesse de combustion, la pression de detonation etait la plus faible pour le propergol B/N (7/3). Un melange de catocene et de chromite de cuivre a multiplie la vitesse par 1,6 tout en reduisant la sensibilite a la temperature.

Eishu Kimura

Papers

Characterization of BAMO/NMMO Copolymers

Insensitive munitions (IM) and combustion characteristics of GAP/AN composite propellants

Thermal decomposition of BAMO copolymers

BAMO/NMMO copolymer with polyester initiation

Effects of Copolymerization Ratio of BAMO/NMMO and catalyst on sensitivity and burning rate of HMX propellant