Preparation and mechanical properties of regenerated cellulose/poly(vinyl-alcohol) physical composite hydrogel

Regenerated cellulose (RCE)/poly(vinyl alcohol) (PVA) composite hydrogels were successfully prepared via physical repeated freezing and thawing method. The structure and properties of the RCE/PVA composite hydrogel were investigated by Fourier transform infrared spectrum, scanning electron microscopy, mechanical and swelling tests. The results revealed that a novel compact dual-network structure was formed between the cross-linked cellulose network and PVA matrix, which can strongly enhance the mechanical properties of the composite hydrogels as expected. Compared with neat PVA hydrogels, a 611% increase in tensile strength of RCE/PVA composite hydrogel from 0.09 to 0.64 MPa and 643% improvement in compressive strength from 0.07 to 0.52 MPa were achieved with the addition of 4 wt% of cellulose. The presence of cellulose is also beneficial to the elasticity of PVA hydrogels. With the incorporation of RCE, the composite hydrogels perform better shape recovery after compression test. Moreover, the addition of RCE has improved the swelling, water-absorbing, and water-retaining properties of the PVA hydrogels significantly.