Facile fabrication and characterization of highly stretchable lignin-based hydroxyethyl cellulose self-healing hydrogel.

In this study, hydroxyethyl cellulose (HEC) and polyvinyl alcohol (PVA) as the framework, borax as the cross-linker, and biomass lignin from pulping black liquors and biorefinery as the plasticizer were used to synthesize the lignin-based HEC-PVA (LCP) self-healing conductive hydrogel with highly stretchable and thermosensitive properties by the one-step fabrication method. Compared with the PVA hydrogel, the maximum storage modulus and the elongation rate was increased by 7 times and 20 times, respectively. Uniformly distributed lignin could increase the mobility and distance of polymer molecular chains, therefore improve the viscoelasticity and stretchability of the LCP self-healing hydrogel. The LCP hydrogel could recover to the original state in 12 s after 10000% shear strain for 4 cycles. The LCP hydrogel also presented good thermosensitivity and electrical conductivity, and were very promising for applications in the fields of 3D printing and wearable electronic devices, that broadened the efficient utilization of biorefinery lignin.