1. n. [Drilling Fluids]
A copolymer of vinyl acetate (ethylenic polymer) and anhydrous maleic acid (a di-hydroxy acid). The vinyl acetate polymer component is usually high molecular weight. As such, with polar groups on the structure, it is used as a flocculant or bentonite extender.
Alternate Form: vinyl acetate-maleic anhydride copolymer