Energetic ABA and (AB)n thermoplastic elastomers

Linear ABA triblock and (AB) n segmented block copolymers of energetic monomers have been synthesized. The rigid and soft blocks are prepared from 3,3‐bis(azidomethyl)oxetane (BAMO) and 3‐nitratomethyl‐3‐methyloxetane (NMMO), respectively. Polymerization of BAMO initiated by triethyloxonium tetrafluoroborate and by spiro(benzoxasilole)/propanediol produced α,ω‐monohydroxy‐PBAMO ( 3 ) and α,ω‐dihydroxy‐PBAMO ( 4 ) of M̄ n 16,000 and 2,000, respectively, and α,ω‐dihydroxy‐PNMMO ( 5 ) of M̄ n = 13,000 was synthesized by the latter method. The block copolymers were prepared from the appropriate telechelic polymers and toluene diisocyanate. The PBAMO—PNMMO—PBAMO copolymer 6 has T m = 82°C, T g = −3°C, and is strongly phase separated even in the melt. It decomposes sharply within 1°C at 224°C evolving 0.69 kJ/g of heat. Copolymer 6 has excellent mechanical properties with elongation of 683% at break, 5.25 MPa stress, and 82% recovery. The (PBAMO—PNMMO) n copolymer 7 has similar thermal properties and spectroscopic characteristic, but is inferior to copolymer 6 in all rheological and mechanical properties.