Growth of 1,3,5‐Triamino‐2,4,6,‐Trinitrobenzene (TATB). II. Control of growth by use of high T g polymeric binders

The remarkable safety characteristics of the high explosive 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) are revolutionizing the design and deployment of nuclear weapons. Kel‐F 800 is used as the binder to obtain high‐density, mechanically stable billets of TATB that can be machined into desired shapes. However, repeated thermal cycling between − 54 °C and 74 °C of high density, pure, and plastic‐bonded TATB billets causes a permanent volume expansion (growth) of about 1.5 vol% to 2.0 vol%. Debonding of the Kel‐F 800 binder occurs during growth, causing a reduction in the mechanical properties of the plastic‐bonded explosive. The coefficient of thermal expansion (CTE) of these TATB billets between ambient temperature and 74 °C is 67.0 × 10 −6 /°C. TATB undergoes a secondary mechanical relaxation just above room temperature, coinciding with the onset of a high CTE, above the glass transition temperature (T g ) of Kel‐F 800. Thus, by judicious selection of a high‐T g binder, we have essentially eliminated growth, stopped the degradation of mechanical properties after thermal cycling, suppressed the secondary mechanical relaxation, and lowered the CTE to 50.0 × 10 −6 /°C between ambient temperature and 74 °C.