Induced Plasticization, a Surface Treatment Technique for Extending the Environmental Capability of Solid Propellant Rocket Motors.
Abstract
A concept is presented for extending the low temperature strain limit of rubber-based solid propellants by means of induced plasticization. The concept is then extended for use as an inner bore treatment for solid propellant rocket motors. The process consists of exposing the cured propellant to a solution of a solvent (Freon-11) and a compatible plasticizing oil. The plasticizer, which alone cannot penetrate into the polymer, is transported by the Freon-11 which acts as a gentle swelling agent. Once the desired penetration depth has been achieved, the lower boiling solvent is removed by vacuum leaving a plasticizer-rich layer capable of withstanding significantly greater strains without cracking. The ability to extend the environmental limits of solid propellants was first demonstrated in a series of laboratory scale tests which include: uniaxial tensile tests, a strain evaluation cylinder (analogue motor) cold soak-to-failure program, and 15-pound static motor firings. The laboratory developed procedures were then scaled-up and demonstrated on three full scale rocket motors. In addition to enhancing strain capability, the potential of the treatment for retarding the propagation of cracks was also demonstrated. Finally, a five-point criterion for a general, optimized treatment procedure for soild propellant rocket motors was presented. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1973
- Accession Number
- AD0906915
Entities
People
- Donald Saylak
Organizations
- Air Force Research Laboratory