A polymer made by reacting a polyisocyanate with a compound having the formula below. R1 is an organic group. R2 is an aliphatic group. R3 is an aliphatic group. The polyisocyanate reactants are at least 50 mol % aromatic polyisocyanates. The reaction forms urea groups from the isocyanate groups of the polyisocyanate and the NH groups of the compound.