Surface additives chemicals are incorporated in full proportion in the sheet. The primary goal of incorporating this substance into paper is to increase overall strength while minimizing dusting, hardness, and other issues. . Suppose papermaking mills wish to obtain enhanced resistance to solvents or increasing concentrations of surface complexation. In that case, they might add polyurethanes such as urethane, styrene acrylates (SA), styrene-maleic anhydride (SMA), or copolymers to thickness starch.