Abstract: A process of preparation of a graft copolymer of (a) styrene and (b) an EPDM rubber by mass polymerization followed by irradiation, for example electron irradiation.

Abstract: Process for manufacturing finely divided polymers of bicyclo [2.2.1] heptene-2 compound comprising the steps of incompletely polymerizing said bicyclo [2.2.1] heptene-2 compound by the ring opening polymerizing technique in the presence of a catalyst system selected from the group comprising a compound of a noble metal of the platinum family and an alcohol-reducing solvent and tungsten hexachloride, an aluminum alkyl and an aromatic solvent, under superatmospheric pressure and in the presence of a quantity of solvent at least equal to that necessary for the solution of said catalyst system and abruptly reducing said pressure at a temperature higher than the vaporization temperature of the reaction mixture under said reduced pressure, whereby an expansion, a division and at least partial drying of the resulting polymer is obtained.