HTPB hydroxy-terminated

CTPB = carboxy-terminated polybutadiene HTPB = hydroxy-terminated polybutadiene PBAN = polybutadiene-acrylic acid-acrylonitrile and PBAA = polybutadiene-acrylic acid. 

TB (or HTPB) = Hydroxy-terminated polybutadiene encapped with toluene diisocyanate at an NCO/OH ratio of 2 to 0 extended with 1,4 butane diol and crosslinked with trimethylolpropane. 

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). 

Hydroxy-terminated polybutadiene (8) (HTPB) has been treated with dinitrogen pentoxide in methylene chloride. The product (9) is an energetic oligomer but is unlikely to find application because of the inherent instability of /3-nitronitrates." Initial peroxyacid epoxidation of some of the double bonds of HTPB followed by reaction with dinitrogen pentoxide yields a product containing vtc-dinitrate ester groups and this product (NHTPB) is of much more interest as an energetic binder (see Section 3.10)." ... 

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. ... 

Hydroxy-terminated polyester (HTPS) is made from diethylene glycol and adipic acid, and hydroxy-terminated polyether (HTPE) is made from propylene glycol. Hydroxy-terminated polyacetylene (HTPA) is synthesized from butynediol and paraformaldehyde and is characterized by acetylenic triple bonds. The terminal OH groups of these polymers are cured with isophorone diisocyanate. Table 4.3 shows the chemical properties of typical polymers and prepolymers used in composite propellants and explosives.E4 All of these polymers are inert, but, with the exception of HTPB, contain relatively high oxygen contents in their molecular structures. 

The polymeric hydrocarbon also acts as a binder of the particles, holding them together so as to formulate a propellant grain. Ammonium perchlorate (AP) is a typical crystalline oxidizer and hydroxy-terminated polybutadiene (HTPB) is a typical polymeric fuel. When AP and HTPB are decomposed thermally on the propellant surface, oxidizer and fuel gases are produced, which diffuse into each other and react to produce high-temperature combustion gases. 

Hydroxy-terminated polybutadiene (HTPB) is considered to be the best binder for obtaining high combustion performance, superior elongation properties at low temperatures, and superior mechanical strength properties at high temperatures. This combination of properties is difficult to achieve in double-base propellants. HTPB is characterized by terminal -OH groups on a butadiene polymer. The other type of butadiene polymer used is carboxy-terminated polybutadiene (CTPB), which is cured with an imine or an epoxy resin. It should be noted that CTPB is somewhat sensitive to humidity, which has an adverse effect on its ageing charac-... 

Typical examples of HCP are hydroxy-terminated polybutadiene (HTPB), car-boxy-terminated polybutadiene (CTPB), hydroxy-terminated polyether (HTPE), hydroxy-terminated polyester (HTPS), and hydroxy-terminated polyacetylene (HTPA). The physicochemical properties of various types of HCP are described in Section 4.2.3. 

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. 

Inert binders Polybutadiene and cellulose derivatives are used as binders for LOVA formulations [24]. The commonly used polybutadiene-based binders are hydroxy-terminated polybutadiene (HTPB) and carboxy-terminated polybutadiene (CTPB)/poly(butadiene-acrylonitrile) (PBAN) while the most commonly used cellulose derivatives are ethyl cellulose (EC), cellulose acetate (CA), cellulose acetate butyrate (CAB) and cellulose... 

Hydroxy-terminated polybutadiene HTPB [Structure (4.4)] prepared by... 

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