Prevention of fouling in polymerization reactors and antistatic agents

In a process in which at least one olefin is polymerized in a hydrocarbon diluent in a turbulent reaction zone to produce particles of polymer which are substantially insoluble in the diluent;

• the method of reducing adherence of polymer particles to the walls of the reaction zone which comprises adding to the reaction medium at least one compound selected from the group consisting of ##STR2## and (3) a compound of either of the foregoing structures having the hydrogen-free nitrogen atoms protonated, where each R is hydrogen, an alkyl group of 1 to 8 carbon atoms or a carboxy group, each R.sub.1 is hydrogen, an alkyl group of 1 to 4 carbon atoms, an aromatic hydrocarbyl group of 6 to 10 carbon atoms or such an aromatic group substituted with an alkyl group of 1 to 12 carbon atoms, and Z is M or M=0, where M is copper, zinc, chromium, iron, nickel, cobalt or vanadium.