Dynamic mechanical and molecular weight measurements on polymer bonded explosives from thermally accelerated aging tests. II. A poly(ester-urethane) binder

Conference · Thu Jan 01 00:00:00 EST 1981

OSTI ID:6866602

Hoffman, D M; Caley, L E

The molecular weight distribution and dynamic mechanical properties of an experimental polymer-bonded explosive, X-0282, maintained at 23, 60, and 74/sup 0/C for 3.75 y were examined, X-0282 is 95.5% 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclo-octane explosive and 4.5% Estane 5703, a segmented poly(ester-urethane). Two mechanical relaxations at about -24 and 42/sup 0/C were found in the X-0282 aged at room temperature for 3.75 years. A third relaxation at about 85/sup 0/C was found in X-0282 aged at 60 and 74/sup 0/C. The relaxation at -24/sup 0/C is associated with the soft segment glass transition of the binder. The relaxation at 42/sup 0/C is associated with the soft segment melting and may also contain a component due to the hard segment glass transition. The relaxation at 85/sup 0/C is probably associated with improved soft segment crystallite perfection. The molecular weight of the poly(ester-urethane) binder decreased significantly with increasing accelerated aging temperature. A simple random chain scission model of the urethane degradation kinetics in the presence of explosive yields an activation energy of 11.6 kcal/mole. This model predicts a use life of about 17.5 years under the worst military operating conditions (continuous operation at 74/sup 0/C).

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore National Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6866602
• Report Number(s): UCRL-85120(Vol.2); CONF-810308-4; TRN: 81-006295
• Resource Relation: Conference: American Chemical Society symposium on the chemistry of engine combustion deposits, Atlanta, GA, USA, 29 Mar 1981
• Country of Publication: United States
• Language: English

Related Subjects

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
CHEMICAL EXPLOSIVES
AGING
MECHANICAL PROPERTIES
MOLECULAR WEIGHT
BINDERS
EXPERIMENTAL DATA
MATERIALS TESTING
PLASTICIZERS
POLYMERIZATION
STABILITY
TEMPERATURE DEPENDENCE
CHEMICAL REACTIONS
DATA
EXPLOSIVES
INFORMATION
NUMERICAL DATA
TESTING
450100* - Military Technology
Weaponry
& National Defense- Chemical Explosions & Explosives