Provided herein are compositions comprising an ionomer and a polyamine or a tertiary polyamide. The polyamine and the tertiary polyamide have a molecular weight of greater than 500 Da and do not contain an ester moiety or a primary amine moiety. The polyamine comprises at least three moieties that are tertiary amines or hindered secondary amines, and the polyamide comprises tertiary amide moieties and no secondary or primary amide moieties. The compositions may optionally include a filler. Further provided are articles such as golf balls and films containing these compositions.