A vulcanizable polymer composition comprising (i) a polymer having a main polymer chain derived from (ia) at least 45 to 75% by weight based on the polymer, of at least one diene monomer, which introduces at least one of a secondary carbon and a tertiary carbon to the main polymer chain, and (ib) in the range of from 20 to 50% by weight based on the polymer, of at least one α,β-ethylenically unsaturated nitrile monomer; (ic) in the range of from 1.5 to 10% by weight based on the polymer of at least one α,β-ethylenically unsaturated dicarboxylic acid monoester monomer, α,β-ethylenically unsaturated dicarboxylic acid monomer, α,β-ethylenically unsaturated dicarboxylic acid anhydride monomer or α,β-ethylenically unsaturated dicarboxylic acid diester as a third monomer, wherein the sum of all monomer units mentioned under (ia), (ib) and (ic) is 100% by weight; wherein the polymer (i) comprises a residual carbon-carbon double bond unsaturation of 5.5 to 0.05 mole percent, (ii) at least one polyamine crosslinking agent wherein such polyamine crosslinking agent is selected from the group consisting of hexamethylene diamine, hexamethylene diamine carbamate, tetramethylene pentamine, hexamethylene diamine-cinnamaldehyde adduct, hexamethylene diamine-dibenzoate salt, 2,2-bis (4-(4-aminophenoxy) phenyl) propane, 4,4'-methylenedianiline, m-phenylenediamine, p-phenylenediamine, 4,4'-methylene bis (o-chloroaniline), isophthalic acid dihydrazide, adipic acid dihydrazide, and sebacic acid dihydrazide, wherein the content of the amine is in the range of from 1.5 to 10 parts by weight based on 100 parts by weight of the polymer (i), and (iii) at least one bi- or polycyclic aminic base which is selected from the group consisting of 1,4-diazabicyclo[2.2.2] octane (DABCO) 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD) and its derivatives. (i) a polymer having a main polymer chain derived from (ia) at least 45 to 75% by weight based on the polymer, of at least one diene monomer, which introduces at least one of a secondary carbon and a tertiary carbon to the main polymer chain, and (ib) in the range of from 20 to 50% by weight based on the polymer, of at least one α,β-ethylenically unsaturated nitrile monomer; (ic) in the range of from 1.5 to 10% by weight based on the polymer of at least one α,β-ethylenically unsaturated dicarboxylic acid monoester monomer, α,β-ethylenically unsaturated dicarboxylic acid monomer, α,β-ethylenically unsaturated dicarboxylic acid anhydride monomer or α,β-ethylenically unsaturated dicarboxylic acid diester as a third monomer, wherein the sum of all monomer units mentioned under (ia), (ib) and (ic) is 100% by weight; wherein the polymer (i) comprises a residual carbon-carbon double bond unsaturation of 5.5 to 0.05 mole percent, (ia) at least 45 to 75% by weight based on the polymer, of at least one diene monomer, which introduces at least one of a secondary carbon and a tertiary carbon to the main polymer chain, and (ib) in the range of from 20 to 50% by weight based on the polymer, of at least one α,β-ethylenically unsaturated nitrile monomer; (ic) in the range of from 1.5 to 10% by weight based on the polymer of at least one α,β-ethylenically unsaturated dicarboxylic acid monoester monomer, α,β-ethylenically unsaturated dicarboxylic acid monomer, α,β-ethylenically unsaturated dicarboxylic acid anhydride monomer or α,β-ethylenically unsaturated dicarboxylic acid diester as a third monomer, (ii) at least one polyamine crosslinking agent wherein such polyamine crosslinking agent is selected from the group consisting of hexamethylene diamine, hexamethylene diamine carbamate, tetramethylene pentamine, hexamethylene diamine-cinnamaldehyde adduct, hexamethylene diamine-dibenzoate salt, 2,2-bis (4-(4-aminophenoxy) phenyl) propane, 4,4'-methylenedianiline, m-phenylenediamine, p-phenylenediamine, 4,4'-methylene bis (o-chloroaniline), isophthalic acid dihydrazide, adipic acid dihydrazide, and sebacic acid dihydrazide, wherein the content of the amine is in the range of from 1.5 to 10 parts by weight based on 100 parts by weight of the polymer (i), and (iii) at least one bi- or polycyclic aminic base which is selected from the group consisting of 1,4-diazabicyclo[2.2.2] octane (DABCO) 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD) and its derivatives.