Biocompatible elastomer of waterborne polyurethane based on castor oil and polyethylene glycol with cellulose nanocrystals

► In our study, biocompatible waterborne polyurethane was synthesized. ► Eucalyptus globulus cellulose nanocrystals were introduced as reinforcing filler. ► The aspect ratio of E. globulus cellulose nanocrystals was 23.87. ► Elongation at break of the nanocomposite films showed no significant reduction. ► Thermal stability of the hard-segment of the waterborne polyurethane was enhanced.