"tructural units, the first one having a perhalogenocarbon chain of the general structure, CnXm??? (C is carbon; X is a halogen such as F, Cl, Br, or I), where the chain may be straight, branched or may be a perhalogenated arylalkyl chain, where n is an integer from about 1 to about 200 and m is an integer from about 3 to about 600; and the second structural unit which does not contain CnXm??? unit" . . . .