particular preferred embodiment the reaction mixture is stirred at room temperature for 4 hours or until the copolymerization reaction is complete the copolymer is next added to sufficient methyl alcohol containing enough hydrochloric acid to inactivate the catalyst the copolymer is recovered using conventional methods for example filtration and dried under vacuum at room temprature overnight it should be noted that isoprene and piperylene in the freeze mix will copolymerize at a much faster rate than the olefins in the mix due to the higher reactivity of the conjugated diolefins and the catalyst system used the copolymer or elastomer will primarily be composed of isoprene and piperylene and contain a minor amount of other c 5 hydrocarbons which comprise 5 percent or less of the elastomer weight the elastomer composition is exemplified by table iv below table iv______________________________________copolymerized elastomerweight percentcomponent broad range preferred range______________________________________isoprene 20 to 90 50 to 80piperylene 5 to 60 20 to 50c sub 5 paraffin andc sub 5 olefin 0 to 5 0 to 3______________________________________ the elastomer produced herein will primarily be composed of isoprene and piperylene and in general have a molecular weight greater than about 4000 with a preferred molecular weight range of from about 10 000 to about 1 000 000 the isoprene and piperylene are present in the copolymer composition at a molar ratio range of from about 10 1 to about 1 2 respectively preferably.