A polyethylene copolymer blend consisting essentially of (A) an ethylene/unsaturated carboxylic ester bipolymer and (B) an ethylene/unsaturated carboxylic ester/carbon monoxide terpolymer. The polyethylene copolymer blend is defined by constituents (A) and (B) and at least one omitted material that would have otherwise restricted a physical property of the blend. The (A) ethylene/unsaturated carboxylic ester bipolymer is defined by features comprising choice of unsaturated carboxylic ester, unsaturated carboxylic ester comonomeric content in weight percent (wt %), and bipolymer melt index (I2; 190° C., 2.16 kg) in grams per 10 minutes (g/10 min.). The (B) ethylene/unsaturated carboxylic ester/carbon monoxide terpolymer is defined by features comprising choice of unsaturated carboxylic ester, unsaturated carboxylic ester comonomeric content in wt %, carbon monoxide comonomeric content in wt %, and terpolymer melt index (I2; 190° C., 2.16 kg) in g/10 min. Also formulations, cured polymer products, strippable semiconductive insulation shield layers, coated conductors, methods of making and using same.