Generally useful polymers are polymers of monoolefins, i.e. compounds having the formula R-CH:CH wherein R is hydrogen, or an aromatic or aliphatic hydrocarbon group such as an aryl or alkyl group, particularly an alkyl group having from 1 to 8 carbon atoms, such as polyethylene, polypropylene, polystyrene, ethylene/propylene copolymers and like polymers; and copolymers of such olefins with one or