Abstract: A polymer composition contains, based on a total weight of the polymer composition: a) 40 wt. % to 99 wt. % of a polyalkenamer derived from at least one cycloalkene having 5 to 12 carbon atoms, and b) 1 wt% to 60 wt. % of graphene. The polyalkenamer has a trans-isomer content larger than 50)wt.° /0 based on a weight of the polyalkenamer. A moulded article can be produced from the polymer composition, which can be a board, a film, a bristle, or a foam. The moulded article can be used as a clothing element, sport element, sealing material, electrically conductive article, friction control element, transportation element, or structural element.