Charakterisierung von BAMO/NMMO-CopolymerenZusammensetzung und Mikrostruktur, Thermolyse und Empfindlichkeit von Copolymeren aus 3,3-Bis(azidomethyl)oxetan (BAMO) rnit 3-Nitratomethyl-3-methyloxetan (NMMO) wurde charakterisiert. Das Molverhaltnis der Monomeren beim Ansatz fur die Copolymerisation war BAMO/NMMO = 8/2, 7/3 und 6/4. Die beobachteten Zusammensetzungen ergaben ein Verhaltnis von 8 1/19, 68/32 und 60/40. Die relative Zusammensetzung der Triaden-Mikrostrukturen stimmte genau mit den theoretischen Werten uberein. Die Copolymerisation von BAMO mit NMMO verlauft idealerweise so, daR das Copolymer fast dieselbe Zusammensetzung hat wie die Monomeren-Anteile. Die Mikrostruktur der Copolymeren war ungeordnet. Poly-BAMO zeigte eine Zersetzung der Seitenketten im Anfangsstadium der Thermolyse, andererseits wurde die Thermolyse von Poly-NMMO durch die Zersetzung der Hauptkette bestimmt. Die BAMO-und die NMMO-Einheiten scheinen sich mehr oder weniger unabhangig voneinander zu zersetzen und behielten ihre individuelle Zersetzungscharakteristik trotz der Copolymerisation bei. Allerdings wird die Reaktion des BAMO aktiviert durch die Warmeentwicklung des NMMO, die bei 40°C auftritt und niedriger ist als die von BAMO. Poly-B/N(7/3) zeigte sehr bemerkenswerte Charakteristiken fur Empfindlichkeit, mechanische Eigenschaften und Zersetzungswarme. Caracterisation de copolymeres BAMO/NMMOOn a caractCrisC la composition et la microstructure, la thermolyse et la sensibilitk de copolymkres composCs de 3,3-bis(azidomtthyl)-oxCtane (BAMO) avec du 3-nitratomethyl-3-m&thyloxttane (NMMO). Le rapport molaire des monomkres utilists dans la copolymerisation Btait BAMONMMO = 8/2, 7/3 et 6/4. Les compositions observCes ont donnC un rapport de 81/19, 68/32 et 60/40. La composition relative des microstructures des triades Ctait en parfait accord avec les valeurs thkoriques. La copolymtrisation de BAMO avec NMMO se dCroule comme un systkme idtal en ce sens que le copolymere a presque la inCme composition que les apports de monomkres. La microstructure des copolymkres Ctait aleatoire. Le poly-Bamo a rCvClt une decomposition des chaines latkrales au stade initial de la thermolyse; d'autre part, la thermolyse du poly-NMMO a CtC dkterminte par la dCcomposition de la chaine principale. Les unit& BAMO et NMMO semblent se decomposer plus ou moins indkpendamment l'une de I'autre et ont conservC leur caracttristique individuelle de dCcomposition en dCpit de la copolymtrisation. Cependant, la rCaction du BAMO est activte par le dtgagement de chaleur du NMMO qui se produit h 40°C et est infkrieur h celui du BAMO. Le poly-B/N(7/3) a rCvC1C des caractkristiques trks intkressantes en ce qui concerne la sensibilitC, les pro-priCtts mtcaniques et la chaleur de dtcomposition. SummaryThe 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...
Sensitivities to the ballistic shock and burn rate characteristics of GAP/AN composite propellants were investigated. Nitrate esters, such as TMETN and NC, were very effective ballistic modifier that provided useable burn rate and pressure rate exponent for minimum signature propellant based on AN. Their low temperature mechanical properties became less sensitive to the temperatures with nitrate esters. Dioctyl adipate platicized propellant showed excellent mechanical properties at operational temperature ranges. The primary initiation mechanism of card gap test was not dominated by the mechanical properties. Although NC significantly increased the critical shock pressure, 14.8% HMX and AP were less effective to the sensitivities. GAP/AN propellants showed excellent IM characteristics to the ballistic shock applied here.
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.
In order to improve of mechanical properties at low temperature region, 3,3‐bis(azidomethyl)oxetan (BAMO), 3‐nitratomethyl‐3‐methyloxetane (NMMO) and polyester (PE) copolymer were synthesized by using polyester initiator with boron trifluoride etherate. The molar ratio of each units in the BAMO/NMMO/PE copolymer was 7.4/2.6/0.39 according to the 1H‐NMR spectrum analysis and was almost exactly the same composition as the monomer fed (7/3/0.33). The relative composition of triad microstructures was same as theoretical value and they were randomly arranged. The PE, which was a replacement of 1,4‐butanediol, acted as an excellent soft segment in the copolymer, and the glass transition point of the elastomer was 4.8 degrees lowered by the replacement. This effect was also verified in the mechanical properties of the composite propellant and the tensile elongation was increased from 15% to 40%percnt; at −40 °C.
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