initiate the second phase of the polymerization a wide variety of crosslinking agents can be utilized in the synthesis of the rubbery polymer some representative examples of crosslinking agents which can be utilized include difunctional acrylates difunctional methacrylates trifunctional acrylates trifunctional methacrylates and divinylbenzene some specific examples of crosslinking agents which can be used include ethylene glycol methacrylate divinylbenzene and 1 4 butanediol dimethacrylate in practice 1 4 butanediol dimethacrylate has proven to be particularly useful as the crosslinking agent in most cases the polymerization will be continued until a high monomer conversion has been attained at this point the rubbery polymer made by the two step batch polymerization process is recovered from the emulsion latex this can be accomplished by utilizing standard coagulation techniques for instance coagulation can be accomplished by the addition of salts acids or both to the latex after the rubbery polymer is recovered by coagulation it is dried it is sometimes advantageous to convert the rubbery polymer into a powder to facilitate its usage in this case it will be beneficial to add a partitioning agent to the rubbery polymer some representative examples of partitioning agents which can be employed include calcium carbonate emulsion polyvinyl chloride and silica calcium carbonate is a highly desirable partitioning agent which can be utilized in such applications a wide variety of thermoplastic resins can be.