Polybutadiene acrylonitrile (PBAN)

copolymer In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are som ...

, also noted as

polybutadiene Polybutadiene utadiene rubber, BRis a synthetic rubber. It offers high elasticity, high resistance to wear, good strength even without fillers, and excellent abrasion resistance when filled and vulcanized. "Polybutadiene" is a collective name fo ...

—

acrylic acid Acrylic acid (IUPAC: prop-2-enoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has ...

—

acrylonitrile Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an im ...

terpolymer In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are som ...

is a copolymer compound used most frequently as a rocket propellant fuel mixed with

ammonium perchlorate Ammonium perchlorate ("AP") is an inorganic compound with the formula . It is a colorless or white solid that is soluble in water. It is a powerful oxidizer. Combined with a fuel, it can be used as a rocket propellant called ammonium perchlorat ...

oxidizer. It was the binder formulation widely used on the 1960s–1970s big boosters (e.g.,

Titan III Titan was a family of United States expendable rockets used between 1959 and 2005. The Titan I and Titan II were part of the US Air Force's intercontinental ballistic missile (ICBM) fleet until 1987. The space launch vehicle versions contribu ...

and Space Shuttle SRBs). It is also notably used in NASA's

Space Launch System The Space Launch System (SLS) is an American Super heavy-lift launch vehicle, super heavy-lift Expendable launch system, expendable launch vehicle used by NASA. As the primary launch vehicle of the Artemis program, Artemis Moon landing progra ...

, likely reusing the design from its Space Shuttle counterpart. Polybutadiene acrylonitrile is also sometimes used by amateurs due to simplicity, very low cost, and lower toxicity than the more common

hydroxyl-terminated polybutadiene Hydroxyl-terminated polybutadiene (HTPB) is an oligomer of butadiene terminated at each end with a hydroxyl functional group. It reacts with isocyanates to form polyurethane polymers. HTPB is a translucent liquid with a color similar to wax pap ...

(HTPB). HTPB uses

isocyanate In organic chemistry, isocyanate is the functional group with the formula . Organic compounds that contain an isocyanate group are referred to as isocyanates. An organic compound with two isocyanate groups is known as a diisocyanate. Diisocyan ...

s for curing, which have a relatively quick curing time; however, they are also generally toxic. PBAN based

composite propellant Ammonium perchlorate composite propellant (APCP) is a solid rocket propellant. It differs from many traditional solid rocket propellants such as black powder or zinc-sulfur, not only in chemical composition and overall performance but also by b ...

s also have a slightly higher performance than HTPB based propellants. PBAN is normally cured with the addition of an

epoxy Epoxy is the family of basic components or Curing (chemistry), cured end products of epoxy Resin, resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide fun ...

resin, taking several days at elevated temperatures to cure.

Usages

PBAN was to be used in the

Constellation program The Constellation program (abbreviated CxP) was a crewed spaceflight program developed by NASA, the space agency of the United States, from 2005 to 2009. The major goals of the program were "completion of the International Space Station" and a " ...

, later canceled, as this

was to be used in the first stage of the

Ares I Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation program. The name "Ares" refers to the Greek deity Ares, who is interpretatio graeca, identified with the Roman god Mars (mythology), Mars. Ares I w ...

rocket in five segments. However future versions of Ares I were discussed using liquid propellants as a potential alternative. PBAN is currently used in the solid rocket boosters on the

SLS SLS may refer to the Space Launch System, a launch vehicle developed by NASA. It may also refer to: Education * Stanford Law School, California, U.S. * Sydney Law School, Australia * Symbiosis Law School, India * Same language subtitling, of ...

rocket.

References

Rocket fuels Acrylate polymers Copolymers Plastics {{rocket-stub