HTPB nitrated

Polymer-based rocket propellants are generally referred to as composite propellants, and often identified by the elastomer used, eg, urethane propellants or carboxy- (CTPB) or hydroxy- (HTPB) terrninated polybutadiene propellants. The cross-linked polymers act as a viscoelastic matrix to provide mechanical strength, and as a fuel to react with the oxidizers present. Ammonium perchlorate and ammonium nitrate are the most common oxidizers used nitramines such as HMX or RDX may be added to react with the fuels and increase the impulse produced. Many other substances may be added including metallic fuels, plasticizers, stabilizers, catalysts, ballistic modifiers, and bonding agents. Typical components are Hsted in Table 1. 

Research efforts are ongoing into the use of dinitrogen pentoxide for the industrial synthesis of nitrated hydroxy-terminated polybutadiene (NHTPB) from epoxidated HTPB (Section 3.10). The reaction of aziridines with dinitrogen pentoxide is an important route to 1,2-nitramine-niU ates and these reactions are discussed in Section 5.8.1. ... 

There are a number of inert binders such as polyester, epoxy, polysulfide, polyurethane which have been reported as binders for composite propellants and plastic bonded explosives (PBXs). At present, hydroxy-terminated polybutadiene (HTPB) is regarded as the state-of-the-art workhorse binder for such applications. However, the recent trend is to use energetic binders such as poly [3,3-bis(azidomethyl oxetane)] [poly(BAMO)], poly (3-azidomethyl-3-methyl oxetane) [poly(AMMO)], PNP, GAP diol and triol, nitrated HTPB(NHTPB), poly(NiMMO), poly(GlyN) and nitrated cyclodextrin polymers poly(CDN) for PBXs and composite propellants in order to get better performance. 

NHTPB [Structure (4.18)] is a liquid polymer, whose viscosity can be varied by changing the percentage conversion of double-bonds to dinitrate ester groups. It is made by conversion of a percentage of the double bonds in HTPB to epoxide groups and then to nitrate-ester groups by the reaction with... 

To improve the performances of a monopropellant engine and reduce the risk linked to the simultaneous presence of an oxidizer and a fuel for the long term storage, the oxidizer can be use alone and after decomposition, the hot gaseous oxygen can burn a solid fuel grain in a hybrid solid/liquid engine (Fig. 13). The proposed IL oxidizers can be concentrated aqueous solution of HAN (hydroxylammonium nitrate) or HAN plus AN (ammonium nitrate) and the fuel polyethylene or HTPB (hydroxy-terminated polybutadiene) (Biddle Sutton, 1985 Ramohalli Dowler, 1995). 

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