This study reported that the intercalation of C20 organoclay was achieved in polyurea (PUr) matrices. The significant reinforcement was observed in a highly crosslinked PUr (HPUr), in which the Young’s modulus, stress and elongation at break was improved by ∼40%, ∼110% and ∼50%, respectively, with the addition of 5 wt% C20. The energy dissipation of HPUrs was more than doubled by 5 wt% C20 at the strain of 50% and 100%. It was also found that the reinforcement was not equally significant in a lowly crosslinked PUr, indicating that macromolecular structure of the PUr matrices was important for optimizing the nano-effect in the nanocomposites
