Three S-G HEUR thickeners were synthesized by a step growth polymerization technique of poly (ethylene oxide) (PEO) and dicyclohexylmethane -4,4'-diisocyanate (H12MDI) and then end capped with two monofunctional aliphatic alcohols. These polymers were mixed together according to the hydrophilic and hydrophobic nature of their segments. Based on this, two sets Of associating polymers were introduced. In one set, the samples had identical hydrophobic segments while in the other one, hydrophilic segments were similar The steady shear viscosity profiles of aqueous solutions of all models were determined. In addition, aqueous binary mixtures with various ratios of the S-G HEUR models were studied using steady state and dynamic rheometry. It is suggested that combinations of associating polymers with different size of hydrophobic segments and similar hydrophilic segments produce an associative polymer-like behavior However the combination of those with similar long hydrophobic segments and different hydrophilic segments at similar weight ratio in solution falls short of displaying an associative polymer - like behavior.