Preparation and characterisation of a high-strength self-healing hydrogel

Abstract

In this paper, two-step cross-linking method was used to prepare a composite hydrogel. Explore the effects of the mass ratio of polyvinyl alcohol to sodium alginate, the concentration of cross-linking agent and the times of freeze-thaw cycle on the strength and self-healing properties of hydrogels. The hydrogel were characterized by Infrared Spectroscopy, X-ray Diffraction and Environmental Scanning Electron Microscopy,the water absorption capacity was evaluated bythe swelling rate and the tensile strength was measuered by Electronic Universal Testing Machine. The results indicated that when the mass ratio of PVA and SA was 30:1, the concentration of sodium tetraborate solution was 10wt%, and freeze-thaw cycle once composite hydrogel had the best comprehensive performance: its maximum tensile strength reached 0.90 MPa, and it has good self-healing performance which can be proved by that its tensile strength could return to 75% of initial level 24 hours after being cutting off.