Rotational cast polyurethane composition prepared from a prepolymer composition comprising: a) an isocyanate-terminated polyurethane prepolymer; and b) a curative agent comprising i) a polyol; ii) an aromatic diamine; iii) a thixotropic aliphatic amine; and iv) a thixotropic colloidal additive, wherein the prepolymer comprises a product produce by the reaction of a polyol with an organic diisocyanate monomer comprising 4,4′-diisocyanato diphenylmethane (MDI), and which prepolymer comprises less than 1.0% by weight of free MDI monomer, based on the toal weight of the prepolymer, exhibits a range of enhanced physical properties compared to those obtained from prepolymers comprising a higher level of free MDI monomer.