was a tough elastic material that resembled a cross linked rubber however the product was soluble in 95 5 toluene methanol indicating that the product was a thermoplastic elastic 34 ionomer 34 about 250 g of polyisobutylene mn 900 was dissolved in 200 ml of xylene at room temperature under a nitrogen blanket to the stirred xylene solution was gradually added 60 g of sulfomaleic anhydride at about 35 u00b0 c the reaction mixture was refluxed for about eight hours and then concentrated by roto evaporation the residue was taken up in 2 5 l of ether and washed twice with 500 ml portions of water the ether solution was dried over mgso 4 filtered and concentrated by roto evaporation to give a sulfomaleated product which analyzed for 0 33 sulfur royalene 521 epdm rubber 50 g mill dried dissolved in 1 000 ml dry xylene was treated with 2 67 g of sulfomaleic anhydride for 4 hours at 130 u00b0 c after cooling the resulting product was neutralized with either zinc methoxide sodium methoxide or zinc acetate in methanol a substantial viscosity increase was noted upon addition of the base additional methanol was added when necessary to reduce the viscosity stirring was continued to 0 5 hour and the polymer was isolated from isopropanol in a high speed mixer the resulting crumb was dried in a vacuum.