A Robust High-order Dual Minimum Algorithm.

This invention relates to a process for the preparation of high density resins by bromination of particles of crosslinked vinylaromatic copolymers of either the gel type or the ionic or non-ionic macroporous type. The invention is characterized in that crosslinked vinylaromatic polymer particles which have been swollen in a solvent are contacted with bromine or a bromine releasing agent in the presence of an oxidizing agent.