Physical and mechanical properties of a vegetable oil based nanocomposite

•Waterborne polyurethane was synthesized using a biobased macrodiol derived from castor oil.•Cellulose nanocrystals (CNC) from Kraft pulp were used as reinforcement for the nanocomposites.•Only 5 wt.% CNC was needed to increase the elastic modulus over 700%.•The tensile properties were reasonably fitted using simple models.•A percolation threshold was inferred from the analysis of the different characterization results.