▎ 摘　　要

NOVELTY - Cast elastomer comprises the reaction product of 10-98 wt.% of at least one isocyanate component, 2-90 wt.% of at least one polyol component, 0.1-20 wt.% of graphene nanoplatelets having an average lateral dimension (x, y) of 1-100 mu m determined by atomic force microscope according to ASTM E2859, an average through-plane dimension (z) of 5-100 nm determined by atomic force microscope according to ASTM E2859 and an oxygen content of 0.01-10 wt.% based on the total weight of the nanoplatelets, and 1-30 wt.% of at least one crosslinker or a chain extender. USE - The cast elastomer is useful in an article (claimed) including rollers, castor, wheels, millable casting, belts, cast, sheet, track, seals, gaskets, scraper blades, screens, sieves, tubing, sprockets, gears, couplings, coatings, mold forms and adhesives. ADVANTAGE - The cast elastomer: has improved mechanical properties e.g. modulus, compression set, Bayshore resilience, stress and break at elongation with a broad shore hardness range at -30 degrees C to 150 degrees C; has a Shore A hardness of 60-99 (preferably 80-99) as determined according to ASTM D2240, a specific gravity of 1.05-1.35 (preferably 1.05-1.15) g/cm3, a tensile strength of 100-40000 (preferably 2000-10000) psi at 23 degrees C as determined by ASTM D412, a Taber abrasion resistance of 2-100 (preferably 2-30) mg as determined according to ASTM D4060 and/or a tear strength of 100-2000 lb-f/in at 25 degrees C as determined according to ASTM D624; and has a glass transition temperature of -60-10 degrees C determined by dynamic mechanical thermal analysis at a heating rate of 3 degrees C/minutes at 0.3% strain and a frequency of 1 Hz torsion mode. DETAILED DESCRIPTION - Cast elastomer comprises the reaction product of (a) 10-98 wt.% of at least one isocyanate component, (b) 2-90 wt.% of at least one polyol component, (c) 0.1-20 wt.% of graphene nanoplatelets having an average lateral dimension (x, y) of 1-100 mu m determined by atomic force microscope according to ASTM E2859, an average through-plane dimension (z) of 5-100 nm determined by atomic force microscope according to ASTM E2859 and an oxygen content of 0.01-10 wt.% based on the total weight of the graphene nanoplatelets, and (d) 1-30 wt.% of at least one crosslinker or a chain extender, where the cast elastomer has a hard segment content of 50-97% and the hard segment content is defined as given in the specification. An INDEPENDENT CLAIM is also included for preparing a cast elastomer comprising (a1) preparing an isocyanate prepolymer comprising the isocyanate component, the polyol component and the graphene nanoplatelets, where the isocyanate prepolymer has an isocyanate index of 1-300 and (b1) reacting the isocyanate prepolymer with the crosslinker or the chain extender to obtain a cast elastomer having the hard segment content of 50-97%.