Polyanionic cellulose, referred to as PAC, is a water-soluble cellulose ether derivative made from chemical modification of natural cellulose. It is an important water-soluble cellulose ether.

Polyanionic cellulose has good heat resistance, salt resistance, and strong antibacterial properties. The mud fluid formulated with this product has good water loss reduction, inhibition and high temperature resistance. Widely used in oil drilling, especially salt water wells and offshore oil drilling.