The present invention relates to polymer composites comprising at least one, optionally hydrogenated, nitrile rubber polymer having a Mooney viscosity (ML 1+4 @ 100.degree. C.) below 30 at least one filler and optionally at least one cross-linking agent, a process for preparing said polymer composite wherein at least one, optionally hydrogenated, nitrile rubber polymer having a Mooney viscosity (ML 1+4 @ 100.degree. C.) below 30, at least one filler and optionally at least one cross-linking agent are mixed and a process for the manufacture of a shaped article comprising the step of injection molding a polymer composite comprising at least one, optionally hydrogenated, nitrile rubber polymer having a Mooney viscosity (ML 1+4 @ 100.degree. C.) below 30, at least one filler and at least one cross-linking agent.