Synthesis And Properties Of BAMO-GAP Copolymers

Energetic thermoplastic elastomer(ETPE)is a key component for the thermoplastic propellants.In this thesis,poly(3,3-bis(azidomethyl)oxetane)(PBAMO)and its tri-block copolymers as well as multi-block copolymers with glycidylazidopolymer(GAP)were prepared.These polymers were characterized by means of FTIR,13C-NMR,1H-NMR and GPC.The thermal properties and the stabilities upon friction and mechanical impact were investigatied.Furthermore the chemical compatibility of the BAMO-GAP copolymer with the energetic ingediants of solid propellant was evaluated.3,3-Bis(chloromethyl)oxetane(BCMO)instead of its bromine counterpart was selected as monomer,which is more cost effective for a possible engineering application.PBAMO was synthesized via a cationic ring opening polymerization of BCMO,followed by azidation with sodium azide.The effects of reaction temperature and reaction time on azidation were studied.An azidation degree of 99% was achieved when azidation was conducted in dimethyl acetamide.Multi-block copolymers of BAMO and GAP were synthesized from PBAMO and GAP with PBAMO as hard segments and GAP as soft segments,respectively.Using high molecular weight GAP as soft segments,the block copolymer exhibits a glass transition temperature below-35°C and melts at about 70°C,which meets the processing requirements as a potential ETPE.In addition,the copolymer remains stable before 230°C.Its impact and friction sensitivity were found to be lower than that of PBAMO homopolymer.The compatibility of BAMO-GAP multi-block copolymer with some common energetic ingrediants used in propellants was tested,indicating BAMO-GAP copolymers were compatible with AP,Al and HMX,providing further possibility as an ETPE candidate.PBAMO-GAP-PBAMO tri-block copolymer was synthesized via cationic ring opening polymerization,using polyepichlorohydrin as macromolecular initiator for the BCMO monomer,followed by azidation.The conditions of polymerization and azidation were optimized.An azidation degree of 98% was obtained and the Mn of the tri-block copolymer was 6242.The Tg of the tri-block copolymer was lower than-40°C,and the melting point was about 70°C.