NOVELTY - A copolymer composition comprises monomer units.    USE - Copolymer composition for use as a copolyelectrolyte to form a polymer blend that is utilized in an article such as membrane, fuel cell, humidification device, electrolyzer, water purification device, battery, ion exchange resin and dental adhesive (all claimed).    ADVANTAGE - The copolymer composition improves proton conductivity of the polyelectrolyte membranes, even at low humidity conditions. The composition forms the polymer blend with high degree of mechanical strength, low swelling property, hydrolytic stability, and low level of sulfur loss in hot water, hot acid, oxidizing and/or reducing environments.    DETAILED DESCRIPTION - A copolymer composition comprises monomer units of formulae (-(CH2-CH(Ar1(R2-R1)p))n-) (A) and (-(CH2-CH(Ar1(R2-R3)q))m-) (B).    Ar1=aryl containing phenylene, naphthalene, or anthrylene (all optionally substituted);    R1=proton, F, substituent, or sulfonate or phosphonate group(s), where the sum of all R1 units comprises two sulfonate or phosphonate groups, or phosphonate or sulfonate group and each sulfonate or phosphonate group has positively-charged counter ions (M+);    M+=proton, alkali metal, alkaline earth metal or positively charged 1-30C organic cation;    R2=bond, 1-14C aryl, 1-14C aliphatic group, 1-14C aliphatic ether or fluorinated perfluorinated analogue;    R3=cross-linking functionality;    n=number of moles of monomer unit(s) having two or more acid groups;    m=number of moles of monomer unit(s) having functional group capable of cross-linking;    p=number of substituents on aryl group of monomer A;    q=number of substituents on aryl group of monomer B, where the monomer A present in the copolymer is 30-99 mole% and the monomer B is present at from 1-50 mole%;and    n+m=2-10000.    INDEPENDENT CLAIMS are also included for the following:    (1) a polymer blend comprising 5-95 weight% of the polymer composition and 5-95 weight% of a matrix polymer    (2) a process for forming disodium 1-vinyl phenyl-2,4-disulfonate, which involves admixing 2,4-disulfonic acid benzaldehyde di-metalic salt, methyltriaryiphosphonium halide, a base and solvent to a reactor to form a slurry, heating the admixture with vigorous stirring, cooling the mixture, separating the disodium 1-vinyl phenyl-2,4-disulfonate solid from the solvent, optionally washing and/or purifying the disodium 1-vinyl phenyl-2,4-disulfonate, and drying the disodium 1-vinyl phenyl-2,4-disulfonate.