Scale up of the polymerization of copolymer ECH/BBrMO as precursor for an energetic polymer

The scale up of the synthesis of copolymer ECH/BBrMO has been performed up to 1 kg scale. The synthesis has been done via cationic polymerization of a mixture of monomers, ECH (epichlorohydrin) and BBrMO (3,3-bis(bromomethyl)-oxetane), using BF3-THF as catalyst and 1,4-dioxane as solvent. BBrMPD (2,2-bis(bromomethyl)-1,3-propanediol) has been used as initiator. It is commercial available and can add to the polymer one additional energetic BAMO (3,3-bis(azidomethyl)-oxetane) unit after the final azidation step in contrast to the inert 1,4-butanediol which is often used in cationic polymerization as initiator. The polymerization parameters have been optimized in order to minimize the content of low molecular weight product (oligomers) which are often created via back biting and transfer reactions at cationic polymerizations. With the initiator BBrMPD and quenching the reaction with water, the copolymer has been hydroxyl end group terminated. The copolymer has been characterized by NRM-, IR-spectra, measuring of glass transition temperature (DSC), molecular weight (GPC) and end group analysis via titration. The halogen substituent of the copolymer can be easily substituted by azide groups to build an energetic polymer.