Cross-linked nanocomposite hydrogels based on cellulose nanocrystals and PVA: Mechanical properties and creep recovery

Cellulose nanocrystal (CNC) reinforced poly(vinyl alcohol) (PVA) hydrogels with a water content of similar to 92% were successfully prepared with glutaraldehyde (GA) as a cross-linker. The effects of the CNC content on the thermal stability, swelling ratio and mechanical and viscoelastic properties of the cross-linked hydro gels were investigated. The compressive strength at 60% strain for the hydrogels with 1 wt% CNCs increased by 303%, from 17.5 kPa to 53 kPa. The creep results showed that the addition of CNCs decreased the creep elasticity due to molecular chain restriction. The almost complete strain recovery (similar to 97%) after fixed load removal for 15 min was observed from the hydrogels with CNCs, compared with 92% strain recovery of the neat cross-linked PVA hydrogels. The incorporation of CNCs did not affect the swelling ratio and thermal stability of the hydrogels. These results suggest the cross-linked CNC-PVA hydrogels have potential for use in biomedical and tissue engineering applications. (C) 2016 Elsevier Ltd. All rights reserved.