Hydroxyl-terminated polybutadiene +Search for Videos

''Hydroxyl-terminated polybutadiene (HTPB)''' is an oligomer+ of butadiene+ terminated at each end with a hydroxyl+ functional group+. It reacts with polyisocyanates+ to form polyurethane+ polymers.

HTPB is a translucent liquid with a color similar to wax paper and a viscosity similar to corn syrup. The properties cannot be precisely stated because HTPB is a mixture+ rather than a pure compound+, and it is manufactured to meet customers' specific requirements. An oligomeric unit typically consists of 5–10 butadiene molecules linked together, with each end of the chain terminated with a hydroxyl [OH] group:

HTPB is usually cured by an addition reaction+ with a polyisocyanate+ compound.

Polyurethanes prepared from HTPB can be engineered for specific physical properties; polyurethanes may be highly elastic or tough and rigid. Some products include: rigid foam insulation panels; durable elastomeric wheels and tires (such as roller coaster+ and escalator+ wheels); automotive suspension bushings+; electrical potting compounds; high performance adhesive+s; surface coatings and surface sealants; synthetic fibers+ (e.g., Spandex+); carpet+ underlay; hard-plastic parts (e.g., for electronic instruments); hoses and skateboard wheels+.

An important application of HTPB is in solid rocket propellant+. It binds the oxidizing agent+ and other ingredients into a solid but elastic mass. The cured polyurethane acts as a fuel in such mixtures. For example, HTPB is used in all 3/4 stages of the Japanese M-5 rocket+ satellite launchers and PSLV+ rocket developed by ISRO+ for satellite launches. JAXA+ describe the fuel as "HTPB/AP/Al=12/68/20" which means, proportioned by mass, HTPB plus curative 12% (binder and fuel), ammonium perchlorate+ 68% (oxidizer), and aluminium+ powder 20% (fuel).

Similar propellants, often referred to as APCP (ammonium perchlorate composite propellant+) are used in larger model rockets. A typical APCP produces 2-3 times the specific impulse+ of the black powder+ propellant used in most smaller rocket motors.

HTPB is also used as a hybrid rocket+ fuel. With N2O (nitrous oxide+, or "laughing gas") as the oxidizer, it is used to power the SpaceShipTwo+ hybrid rocket motor developed by SpaceDev+.

reflist:

*, from Cray Valley, a manufacturer of HTPB
* description of synthesis and other details.

Category:Polyols+
Category:Organic polymers+
Category:Rocket fuels+


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 Hydroxyl-terminated polybutadiene+ Hydroxyl-terminated polybutadiene (HTPB) is an oligomer of butadiene terminated at each end with a hydroxyl functional group.