Cross-linked polyvinyl alcohol (PVA) foams reinforced with cellulose nanocrystals (CNCs)

Poly(vinyl alcohol) (PVA) foams reinforced with cellulose nanocrystals (CNCs) were prepared with formaldehyde as a crosslinking agent. Two initial reaction times (10, 120 s) and the addition of CNCs (0-2 wt% based on total reaction suspension) were found to affect the foam density, water uptake, morphology and mechanical properties. A longer initial reaction time resulted in higher mechanical properties and density, due to the small pore size. The addition of CNCs induced a progressive decrease in the pore diameter and an increase in the foam density, as well as improved mechanical properties. With 1.5 wt% CNC content, the compressive strength of the PVA foams was significantly improved from 7 to 58 kPa for 10 s-initial reaction time and from 65 to 115 kPa for 120 s-initial reaction time. Results showed that the cross-linked PVA foams with CNC had promising properties for use in biomedical applications.