Polymerization catalyst activators, method of preparing and their use in polymerization processes

New polymerization catalyst activators are disclosed which include a heterocyclic compound, which may or may not be substituted, and an aluminum alkyl or an aluminoxane. Supported activators of the invention include the heterocyclic compound, combined with an alkylaluminum or aluminoxane, and a support material, preferably a silica support material. Also disclosed are methods for preparing these catalyst activators and polymerization processes utilizing same.