the viscosity to 10 cp the latex was found to analyze 35 by weight of polyisoprene acid hydrolysis of 4 g of isolated starch polyisoprene graft copolymer in 1n hcl for 2 hours at 95 u00b0 c produced 1 45 g of a rubbery material that analyzed as polyisoprene the procedure to make starch polyisoprene latexes as described in example 11 was also used to make starch terpolymer graft latexes of acrylonitrile isoprene and t butylaminoethylmethacrylate the latter vinyl amine permits the insertion of cationic character in the vinyl side chain to 13 g of starch gelatinized in 300 ml of water for 1 hour at 95 u00b0 c under nitrogen and then cooled to 25 u00b0 c were added 15 ml of acrylonitrile and 1 5 g of t butylaminoethylmethacrylate adjusted to ph 4 after stirring the mixture for 5 minutes 15 ml of isoprene were added and stirring continued for another 5 minutes finally 7 ml of 0 2n cerium iv reagent in 0 1n hno 3 were added and reaction allowed to proceed at 25 u00b0 c for 48 hours the reaction mixture was blended for 3 minutes and the ph adjusted to 5 5 with 1n naoh fifty milliliter aliquots were sonified for 3 minutes at 20 khz to form the latex analysis of the solid graft copolymer isolated from the latex by alcohol precipitation showed that 42 by weight was vinyl polymer and of this 31 was polymerized acrylonitrile films made.