Energetic polymers Explosive binder

Some compounds of general structures (137) and (138) have hydroxy or carboxy termini, making them potential monomers for the synthesis of energetic polymers (binders) and plasticizers for both explosive and propellant formulations. ... 

To summarize, the cost of production of NHTPB is lower than that of poly(NiMMO) or Poly(GlyN). However, NHTPB s performance is poor in comparison to them. On the basis of trials conducted so far, it seems likely that poly(GlyN) will prove to be a world leader in the field of energetic polymers. A summary of the properties of energetic binders for use with both explosives and propellants is given in Table 4.6a,b. 

In thermobaric weapons, highly aluminized secondary explosives can be used instead of monopropellants. For example, RDX in combination with a binder and a large quantity of aluminum (fuel rich) can be used. Research is currently being undertaken to investigate energetic polymers which could possibly be metallized for possible applications. 

However, the use of such binders (usually inert polymers) brings down the overall energy of the systems this can be improved by the use of an energetic binder such as TNT, which is a low melting explosive and also has the capability of binding explosive particles. 

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. 

HMX-based PBXs were developed for projectiles and lunar seismic experiments during the 1960s and early 1970s using Teflon (polytetra-fluoroethylene) as the binder. PBXs based on RDX and RDX/PETN have also been developed and are known as Semtex. Development is continuing in this area to produce PBXs which contain polymers that are energetic and will contribute to the explosive performance of the... 

One disadvantage of the polymer-bonded explosives of the first generation, is that the non-energetic binder (polymer) and plasticizer lessened the performance. To overcome this problem energetic binders and plasticizers have been developed. The most prominent examples for energetic binders are (Fig. 1.5, a) ... 

By very carefully controlling the reaction of pentaerythritol in nitric acid, PETRJN (Figure 3.29) instead of PETN can be obtained. PETRIN is not a particularly desirable explosive, but because of the hydroxyl group left on the last of the outer carbons, this material has one particularly useful feature. The hydroxyl can be reacted to the acid group in acrylic acid to form a polymerizable material, PETRJN-acrylate. PETRJN-acrylate polymer, a plastic, is used as an energetic binder in some composite rocket propellants. 

Epichlorohydrin or chloromethyloxirane is manufactured from allyl chloride, and, in 2006, had a merchant price of US 1.66 kg [4]. It is used as a building block in the manufacture of plastics, epoxy resins, phenoxy resins, and other polymers, and as a solvent for cellulose, resins, and paints, and has also found use as an insect fumigant. Epoxy resins (aryl glycidyl ethers) are manufactured successfully in large scale (1.2 x 10 metric tons in 2000) [26] and are widely used in a variety of industrial and commercial applications [27]. These are made by addition reactions of epichlorohydrins or by epoxidation of allyl ethers or esters (Table 1.1). Epichlorohydrin can be reacted with an alkali nitrate to produce glycidyl nitrate, an energetic binder used in explosive and propellant compositions. 

Methods to dissolve the polymer binders used to hold energetic materials also are being developed. Polyurethane-based polymers are commonly used as binders for propellants and explosives. By undergoing hydrolysis at 230°C (445°F), the polyurethane groups in the binder split. The mixture is then treated by solvent extraction to recover both polyols and energetic materials from the binder. 

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