Polyurethanes, as well known, have been so far a minor player in the whole composite world, with unsaturated polyesters and epoxies having the lion's shares among thermo-sets. Future outlook is although very positive with sizable lands of opportunities being opened in consideration of the increased concern for styrene emission (associated to most common unsaturated polyesters and vinyl esters) and the quest for fast, automated and quality consistent production. In fact, polyurethanes are enabling a broad range of technologies for composite production. These can be described in a two dimensional array as a function of polyurethane density (full density or expanded) and the type of reinforcement (short-fibers or platelets, chopped fibers, wovenot-woven mats, and endless fibers). Dow has been actively developing polyurethanes formulations to be applied in a broad range of composite manufacturing technologies. This paper will specifically focus on the study of the mechanical properties of laminates obtained by the continuous method of pultrusion using different resins and the same glass fiber reinforcement. Specific focus is put on the contribution of the polymer matrix to the final properties of the composite.
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