Phase separation in poly(methyl methacrylate)-block-poly(2,3-dibromopropyl methacrylate) copolymers

AB block copolymers poly(methyl methacrylate)‐block‐poly(2,3‐dibromopropyl methacrylate) were prepared by a two‐stage process involving the sequential anionic polymerization of methyl methacrylate and allyl methacrylate followed by bromination of the pendant allylic groups. Transmission electron microscopy of thin sections of cast films revealed phase separation, the morphology depending upon composition of the block. In particulate form these copolymers gelled with methyl methacrylate to form doughs that could be moulded and heat cured to produce hard X‐ray opaque copolymers.