1. n. [Drilling Fluids]

A copolymer of polystyrene (containing sulfonate groups on the ring) and anhydrous maleic acid (a di-hydroxy acid). The sulfonated ring-structure polymer component is anionic and usually low to moderate in chain length and molecular weight. As such, with negative groups on the structure (amount of negativity depending on degree of sulfonation), it is used as a clay deflocculant for bentonite-based water mud. It is especially stable to temperature up to around 400°F [204°C], and often used in high-density muds to stabilize rheology. Lignosulfonate is used for this purpose up to about 300°F [149°C] and then SSMA polymeric deflocculant is often phased into the mud system for drilling deeper and hotter zones.

Alternate Form: sulfonated polystyrene-maleic anhydride copolymer