Polymeric pyrolant

Polymeric materials used as fuel components of pyrolants are classified into two types active polymers and inert polymers. Typical active polymers are nitropoly-mers, composed of nitrate esters containing hydrocarbon and oxidizer structures, and azide polymers, containing azide chemical bonds. Hydrocarbon polymers such as polybutadiene and polyurethane are inert polymers. When both active and inert polymers are mixed with crystalline oxidizers, polymeric pyrolants are formed. 

Since pyrolants are mixtures of various chemicals, such as crystalline particles, metal particles, metal oxide particles, and/or polymeric materials, the physico-... 

The selechon of fuel components to be mixed with oxidizer components is also an important issue in the development of pyrolants for various applications. Metal particles are used as fuel components to develop small-scale pyrolant charges as deployed in igniters, flares, and fireworks. Non-metal particles such as boron and carbon are used to formulate energetic pyrolants. Polymeric materials are commonly used as fuel components to develop relatively large-scale pyrolant charges, such as gas generators and fuel-rich propellants. 

Aluminum (Al) is a silver-colored light and soft metal used as a major component of aluminum alloys, which are used to construct aircraft and vehicles, similar to Mg alloys. However, Al is known as a readily combustible metal. Thus, Al particles are used as major fuel components of pyrolants. Al particles are mixed with ammonium perchlorate particles and polymeric materials to form solid propellants and underwater explosives. The reaction between aluminum powder and iron oxide is known as a high-temperature gasless reaction and is represented by ... 

The incorporation of magnesium particles into fluorine-containing polymeric materials, such as polyfluoroethylene (Tf) or vinyUdene fluoride hexafluoropropene polymer (Vt), generates energetic pyrolants. The magnesium particles are oxidized by fluorine molecules eliminated from these polymers to produce high-tempera-ture magnesium fluoride. 

In general, pyrolants composed of a polymeric material and AN particles are smokeless in character, their burning rates are very low, and their pressure exponents of burning rate are high. However, black smoke is formed as i decreased and carbonaceous layers are formed on the burning surface. These carbonaceous layers are formed from the undecomposed polymeric materials used as the matrix of the pyrolant. When crystalline AN particles are mixed with GAP, GAP-AN pyrolants are formed. Since GAP burns by itself, the GAP used as a matrix for AN particles decomposes completely and bums with the oxidizer gases generated by the AN particles. 

HMX and RDX are energetic materials that produce high-temperature combustion products at about 3000 K. If one assumes that the combustion products at high temperature are HjO, Nj, and CO, rather than COj, both nitramines are considered to be stoichiometricaUy balanced materials and no excess oxidizer or fuel fragments are formed. When HMX or RDX particles are mixed with a polymeric hydrocarbon, a nitramine pyrolant is formed. Each nitramine particle is surrounded by the polymer and hence the physical structure is heterogeneous, similar to that of an AP composite pyrolant... 

A mixture of B and AP particles formulates an energetic B-AP pyrolant. A small amount of polymeric material is added to serve as a binder of the B and AP parti-... 

When AN powder is mixed with a polymeric material, the oxygen gas produced by the decomposition of the AN powder reacts with the hydrocarbon fragments of the thermally decomposed polymeric material. The major combustion products are GO2 and H2O. Nitropolymers are not used as fuel components of AN pyrolants because of the reaction between the NO2 formed by their decomposition and the AN powder. This reaction occurs very slowly and damages the physical structure of the AN pyrolant. Instead, polymeric materials containing relatively high mass fractions... 

As described in Sections 4.2.4.1 and 5.2.2, GAP is a unique energetic material that burns very rapidly without any oxidation reaction. When the azide bond is cleaved to produce nitrogen gas, a significant amount of heat is released by the thermal decomposition. Glycidyl azide prepolymer is polymerized with HMDI to form GAP copolymer, which is crosslinked with TMP. The physicochemical properties of the GAP pyrolants used in VFDR are shown in Table 15.3.PI The major fuel components are H2, GO, and G(g), which are combustible fragments when mixed with air in the ramburner. The remaining products consist mainly of Nj with minor amounts of GOj and HjO. 

The starting amino acid for nylon-11 is produced from methyl ricinoleate [141-24-2], which is obtained from castor oil (qv). The methyl ricinoleate is pyrolized to methyl 10-undecylenate [25339-67-7] and heptanal [111-71-7]. The unsaturated ester is hydrolyzed and then converted to the amino acid by hydrobromination, followed by ammoniation and acidification. The CO-amino acid product is a soft paste containing water, which is dried in the first step of the polymerization process. 

FLUIDIZED-BED PYROL YSIS OF OTHER POLYMERIC WASTES... 

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