2-Acrylamido-2-methylpropane sulfonic acid
2-Acrylamido-2-methylpropane sulfonic acid (AMPS) was a trademark name by The Lubrizol Corporation. It is a reactive, hydrophilic, sulfonic acid acrylic monomer used to alter the chemical properties of wide variety of anionic polymers.
Source: Wikipedia — 2-Acrylamido-2-methylpropane sulfonic acid (CC BY-SA 4.0)