an energetic material while also increasing its specific energy yield. Energetic plasticizers are usually preferred to non-energetic plasticizers, especially for solid rocket propellants. Energetic plasticizers reduce the required mass of propellant, enabling a rocket vehicle to carry more payload or reach higher velocities than would otherwise be the case. However, safety or cost considerations may demand that non-energetic plasticizers be used, even in rocket propellants. The solid rocket propellant used to fuel the Space Shuttle solid rocket booster employs HTPB, a synthetic rubber, as a non-energetic secondary fuel. Plasticizers for energetic materials Here are some energetic plasticizers used in rocket propellants and smokeless powders: Nitroglycerine (NG, aka "nitro", glyceryl trinitrate) Butanetriol trinitrate (BTTN) Dinitrotoluene (DNT) Trimethylolethane trinitrate (TMETN, aka Metriol trinitrate, METN) Diethylene glycol dinitrate (DEGDN, less commonly DEGN) Triethylene glycol dinitrate (TEGDN, less commonly TEGN) Bis(2,2-dinitropropyl)formal (BDNPF) Bis(2,2-dinitropropyl)acetal (BDNPA) 2,2,2-Trinitroethyl 2-nitroxyethyl ether (TNEN) Due to the secondary alcohol groups, NG and BTTN have relatively low thermal stability. TMETN, DEGDN, BDNPF, and BDNPA have relatively low energies. NG and DEGDN have relatively high vapor pressure. See also Conservation and restoration of plastic objects References External links Plasticisers Information Centre Glass transition DIDP, *DINP, DBP, BBP, *DEHP, Risk Assessment Reports by the European Chemicals Bureau (ECB). Cement Concrete Concrete admixtures