Energetic Oxetane Thermoplastic Elastomer Binders
Abstract
Energetic oxetane-based (AB)n block copolymers have been prepared that, are the first examples of this class of materials that exhibit true elastomeric properties (greater than 100 percent recoverable strain). The materials are prepared, by separately synthesizing the A and B blocks as hydroxyl-terminated telechelic prepolymers then linking the materials using optimized isocyanate chemistry. The individual blocks are prepared using the activated monomer polymerization which allows careful control of molecular weight and functionality. A large number of various hard and soft block combinations were prepared. The hard block was always a poly(3,3- bis(azidomethyl)oxetane) (BAMO) and a series of soft blocks were examined which were based on 3-azidomethyl-3-methyloxetane (AMMO), 3-nitratomethyl-3- methyloxetane (NMMO) and random copolymers of these two monomers with BAMO. Chemical and mechanical measurements on the block copolymers prepared showed that BAMO-AMMO (AB)n materials exhibited the best overall properties. Initial materials exhibited unacceptably high melt viscosities but minor changes to the linking reaction afforded materials with much lower melt viscosities. These materials were mixed with bimodal AP and with bimodal CL-20 at a 65 percent solids loading. Mechanical properties were encouraging. Later mixes replaced 15 percent of the polymer with aluminum to afford an 80 percent solids propellant with encouraging mechanical properties. All mixes were prepared in a small vertical mixer and processed at roughly 95 deg C.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1992
- Accession Number
- ADA278307
Entities
People
- Richard S. Miller