Experimental and Modeling Analysis of the Effect of Aging on the High Explosive PBX 9404

Explosives and propellents are currently being stored for longer than originally intended, in some cases 50 years or more. Storage facilities for these materials often lack climate control and therefore temperature and humidity can vary significantly. Many explosives and explosive constituents are known to degrade with age, particularly nitrocellulose which is a constituent of PBX 9404. In this work, we build on our previous effort to address this concern for PBX 9404 through measurements of detonation velocity and front shape in unconfined rate stick testing, and product equation-of-state in confined cylinder expansion tests. In previous work, we've reported the results of CYLEX tests conducted with PBX 9404 machined from billets aged 37.5 and 46 years, and front-curvature rate sticks from billets aged ~54 years. Here, we report the results of two additional PBX 9404 CYLEX tests conducted on material aged ~54 years (the same age as the recently reported rate sticks) and ~34 years. Comparison of the wall motion between the CYLEX tests suggests that the rate of performance decrease with age slows substantially after 46 years.