Nitrated hydroxy-terminated polybutadiene

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. ... 

The synthesis of nitrated hydroxy-terminated polybutadiene (NHTPB) (44) from the reaction of partially epoxidized hydroxy-terminated polybutadiene with dinitrogen pentoxide... 

N. (1989) Nitrated hydroxy-terminated polybutadiene (NHTPB) a new energetic binder. Proc. 14th Inti. Pyrotech. Seminar, Henry ling Press, Dorset, UK, pp. 105-111. 

Scheme 4.4 Synthesis of Nitrated Hydroxy-terminated Polybutadiene(NHTPB).

Composite proplnts, which are used almost entirely in rocket propulsion, normally contain a solid phase oxidizer combined with a polymeric fuel binder with a -CH2—CH2— structure. Practically speaking AP is the only oxidizer which has achieved high volume production, although ammonium nitrate (AN) has limited special uses such as in gas generators. Other oxidizers which have been studied more or less as curiosities include hydrazinium nitrate, nitronium perchlorate, lithium perchlorate, lithium nitrate, potassium perchlorate and others. Among binders, the most used are polyurethanes, polybutadiene/acrylonitrile/acrylic acid terpolymers and hydroxy-terminated polybutadienes... 

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. 

Solid rockets carboxy- or hydroxy-terminated polybutadienes, ammonium perchlorate, ammonium nitrate, HMX, RDX, polysulphides, nitrocellulose, nitrate esters, nitramines, waxes, asphalts, oils, and resins. 

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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