The present invention provides a cross-linkable functionalized isocyanate composition comprising (1) a functionalized isocyanate product being the reaction product of (i) an isocyanate component having at least two isocyanate groups and (ii) an ethylenically unsaturated component having at least one functional group that is reactive with an isocyanate group of the isocyanate component and at least one ethylenically unsaturated group, wherein the isocyanate component and the ethylenically unsaturated component are selected so that the functionalized isocyanate product has at least three ethylenically unsaturated groups, (2) a monomer component comprising a cross-linking monomer having at least two ethylenically unsaturated groups, and (3) a reinforcing component. Embodiments of the invention being resins that have been cross-linked and cured demonstrate high heat deflection temperature and excellent tensile and flexural properties.