Polymaleic acid is the homopolymer of maleic acid. It is very stable in presence of chlorine and other oxidizing biocides. It has good scale inhibition and high temperature resistance properties. Therefore, it can be used in the water desalination plants. It is also an excellent calcium carbonate antiscalant upon high temperature and in the high alkaline cooling water systems. In addition, it can be used in combination with zinc salts as a corrosion inhibitor. It can also be used as concrete additive and for crude oil evaporation. It can be manufactured through the polymerization of maleic anhydride I an aromatic hydrocarbon upon 60° to 200° C.