Abstract: The tetrapolymer scale inhibitor of MAAAAMSMAS, denoted as PMAAS, is prepared by aqueous solution polymerization and phosphonylation of monomers, i.e., maleic anhydride(MA), acrylic acid(AA), acrylamide(AM), sodium methyl allysulfonate(SMAS) etc. The relationship between such factors as the tetrapolymer dosage, Ca2+ concentration, solution pH and temperature etc. on the scale inhibitor are comprehensively discussed, the changes between crystals of the preliminarily studied with environment scanning electronic microscope (ESEM). The scale inhibition percentage could reach 99% for CaCO3 and 88.5% for CaSO4 respectively, when pH=7 and 7mg/L of PMAAS is used. Additionally, the comparison with corresponding products indicates that the scale inhibition performance of calcium carbonate and calcium sulfate is of advantage.

Key words: scale inhibitor, tetrapolymer, maleic acid, acrylamide, calcium carbonate, calcium sulfate, organophosphonate acid