BAMO

BAMO monomer is synthesized by replacing the C-Cl bonds of 3,3-bis(chlorom-ethyl) oxetane (BCMO) with C-N3 bonds.I BAMO polymer has two N3 bonds per BAMO monomer unit. BAMO polymer is obtained by polymerizing the monomer 

Since BAMO polymer is a solid at room temperature, BAMO monomer is copolymerized with tetrahydrofuran (THF) in order to formulate a liquid BAMO copolymer that is used as a binder in propellants and explosives, as shown in Fig. 4.9. The terminal OH groups of the BAMO-THF copolymer are cured by reaction with the NCO groups of hexamethylene diisocyanate (HMDl) and then cross-linking is carried out with trimethylolpropane (TMP). The physical properties of such a copolymer with a BAMO/THF composition of 60/40 mol% are shown in Table 4.7.1151 

BAMO is also copolymerized with nitratomethyl methyl oxetane (NIMO) to formulate the energetic liquid polymer BAMO-NIMO. Since NIMO is a nitrate ester containing an -O-NO2 bond in its molecular structure, BAMO-NIMO copolymer is more energetic than BAMO-THF copolymer. The chemical structures of BAMO and NIMO are both based on the oxetane structure, and the structure of the BAMO-NIMO copolymer is shown in Fig. 4.10. 

The physical properties of the copolymer, such as viscosity, elasticity, and hardness, are tuned by adjusting the molecular mass through appropriate selection of m and n. 

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The energetic nature of the azido group makes its incorporation into energetic polymers and binders very desirable. 3,3-Bis(azidomethyl)oxetane (BAMO) (28) and 3-azidomethyl-3-methyloxetane (AMMO) (33) are energetic monomers which on polymerization result in the energetic polymers poly[BAMO] (32) and Poly[AMMO] (34), respectively, both of which are under evaluation as potential energetic alternatives to HTPB in composite propellant formulations. ... 

Azide polymers such as GAP and BAMO are also used to formulate AP composite propellants in order to give improved specific impulses compared with those of the above-mentioned AP-HTPB propellants. Since azide polymers are energetic materials that burn by themselves, the use of azide polymers as binders of AP particles, with or without aluminum particles, increases the specific impulse compared to those of AP-HTPB propellants. As shown in Fig. 4.15, the maximum of 260 s is obtained at (AP) = 0.80 and is approximately 12 % higher than that of an AP-HTPB propellant because the maximum loading density of AP particles is obtained at about (AP) = 0.86 in the formulation of AP composite propellants. Since the molecular mass of the combustion products. Mg, remains relatively unchanged in the region above (AP) = 0.8, decreases rapidly as (AP) increases. 

Binder (energetic fuel) GAP, BAMO, AMMO, NIMO... 

RDX, HMX, TNT, HNIW, AP, AN GAP-THF, BAMO-AMMO, BAMO-NIMO Nylon, Viton, polyester-styrene, HTPB, polyurethane, silicone resin fluoronitropolymer, TEGDN Al, Mg, Mg-Na alloy, B, Zr... 

Fig. 5.19 BAMO, containing two C-N3 bonds, decomposes with rapid heat release accompanied by a mass fraction loss of 0.3. On the other hand, BMCO, containing C-CI bonds, decomposes relatively smoothly without heat release.

Fig. 5.20 The exothermic peak temperature and decomposition temperature of BAMO shift to higher values as the heating rate is increased.

The heat of decomposition, Qj, of BAMO copolymer containing different levels of N3 bond density, KN3), is shown as a function of KN3) in Fig. 5.21. BAMO prepolymer is copolymerized with THF. The N3 bond density is varied by adjusting the mass fraction ratio of BAMO prepolymer and THF. 

The condensed-phase reaction zone of a burning-interrupted BAMO copolymer is identified by infrared (IR) spectral analysis. In the non-heated zone, the absorption of the N3 bond, along with the absorptions of the C-O, C-H, and N-H bonds. 

Fig. 5.21 Heat of decomposition increases with increasing N3 bond density in BAMO copolymer.

Fig. 5.22 The burning rate of BAMO copolymer increases with increasing heat of decomposition and aiso with increasing Nj bond energy.

Fig. 5.23 The burning rate of BAMO/ THF copolymer increases as the mass fraction of BAMO is increased at constant pressure.

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