TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The filler is carbon black.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The divinyl aromatic compound is selected from divinyl toluene, divinyl xylene, divinyl naphthalene, divinyl pyridine, diisopropenylbenzene and/or divinyl benzene. The peroxide curing agent is selected from dialkylperoxide, ketalperoxide, aralkylperoxide, peroxide ether, or peroxide ester (preferably di-tert-butylperoxide, bis-(tert-butylperoxyisopropyl)-benzene, dicumylperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexane, 2,5-dimethyl-2,5-di(tert.-butylperoxy)-hexene-(3), 1,1-bis-(tert-butylperoxy)-3,3,5-trimethyl-cyclohexane, benzoylperoxide, tert-butylcumylperoxide and/or tert-butylperbenzoate).    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The olefin polymer is EP(D)M (ethylene propylene diene monomer) rubber (2 - 45, preferably 10 - 30 phr). The non-polymeric multi-unsaturated peroxide curable cure modifier (1 - 15, preferably 2 - 10 phr), is selected from divinyl aromatic compound and/or polyfunctional monomer containing an electron attractive group. The butyl rubber polymer is present in an amount of 55 - 98 (preferably 70 - 90) phr. The polyfunctional monomer comprises an electron attractive group which is selected from trimethylolpropane tri(meth)acrylate, polyethylene glycol di(meth)acrylate, ethylene di(methacrylate), ethylene glycol di(meth)acrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, tetramethylolmethane tetracrylate and/or polypropylene glycol di(meth)acrylate. The rubber compound further comprises at least one filler. EXAMPLE - A ruber compound was prepared by blending commercial LANXESS Butyl RB 402 (RTM: butyl rubber) (70 parts) and Buna EP T 3950 (RTM: commercial EPDM (ethylene propylene diene monomer) (30 parts) in a Brabender mixer. The remaining ingredients in the formulation were: IRB #7 (RTM: carbon black) (50 phr), divinyl benzene (DVB) (10 phr), and DI-CUP 40C (RTM: peroxide curing agent) (5 phr). The cured compound gave the following test results: delta torque of 25.14 dNm, Shore A hardness of 68 points, ultimate tensile of 8.56 MPa and ultimate elongation of 121%.