Selecting hydroxy-terminated polybutadiene for high strain propellants

In selection of hydroxy-terminated polybutadiene from commercial lots thereof for manufacture of propellants for rocket motors with specified physical characterisitics wherein said manufacture includes crosslinking said hydroxy-terminated polybutadiene with an isocyanate crosslinking agent reactive therewith and said hydroxy-terminated polybutadiene is made with a catalyst such as hydrogen peroxide, an improved quality control procedure adapted to distinguish between hydroxy-terminated polybutadiene in commercial lots thereof that are otherwise like appearing, but sufficiently chemically different to yield propellants of diverse strain characteristics, said improved quality control procedure comprising:

• selecting samples of said hydroxy-terminated polybutadiene from each of said commercial lots prior to manufacture of propellants therewith, said samples being of sufficient size to perform an NMR analysis on each;
• performing said NMR analysis on each of said samples to determine whether there is more or less than about 3% of combined cis and trans epoxy groups based on the total of cis-, trans and vinyl-hydroxy groups and cis- and trans-epoxy groups in each of said samples;
• using only hydroxy-terminated polybutadiene having less than about 3% of combined cis and trans epoxy for manufacture of high strain propellants.