OLYACRYLAMIDE
Polyacrylamide is a condensation polymer with an unusual and useful property. The structure of polyacrylamide
is similar to that of polyethylene, but having a hydrogen on every other carbon replace by an amide group,
–CONH . The molecule is composed of repeating –CH –CH(CONH )– units. The amide groups allow for linking 2 2 2
between polymer strands. The –CONH group from one molecule can react with the same group of another molecule, 2
forming a link between them with the structure –CONHCO–. This produces a network of polymer chains, rather like
a tiny sponge. The free, unlinked amide groups, because they contain –NH groups, can form hydrogen bonds with 2
water. This gives the tiny cross linked sponges a great affinity for water. Polyacrylamide can absorb many times its
mass in water. This property is useful in a variety of applications, such as in diapers and in potting soil. The
polyacrylamide will release the absorbed water if a substance that interferes with hydrogen bonding is added. Ionic
substances, such as salt, cause polyacrylamide to release its absorbed water. [For more information about this
polymer