The most efficient catalyst for the synthesis of polyacrylonitrile from acrylonitrile monomer is an initiator, typically a redox system or a persulfate. These initiators help to start the polymerization process by generating free radicals. Examples of efficient catalysts include ammonium persulfate, potassium persulfate, and azobisisobutyronitrile AIBN . The choice of catalyst depends on the specific reaction conditions and desired properties of the final product.