This study aims to develop a double-network (DN) hydrogel with excellent mechanical properties, self-healing ability, and fatigue resistance to solve the common drawbacks of the existing single-network (SN) hydrogels with low strength and semi-interpenetrating network (Semi-IPN) hydrogels with incompatible toughness and dynamic performance. Leveraging the synergistic effect of a hydrophobically associating polyacrylamide (P(SMA-AM), which can be abbreviated as HPAAm) network and a sodium tetraborate decahydrate (Borax)-ionically cross-linked konjac glucomannan (KGM) network, the P(SMA-AM)/KGM-Borax double-network hydrogel is successfully prepared. The experiment systematically studies the effects of different Borax and KGM contents on the hydrogel’s properties and analyzes its performance through characterization methods such as infrared spectroscopy, scanning electron microscopy, mechanical tests, and self-healing experiments. The results show that when the KGM content is 7.5 wt % and the Borax content is 1.5 wt %, the hydrogel exhibits optimal comprehensive properties, with a fracture strength of 0.34 MPa, a toughness of 2.12 × 103 kJ m–3, a Young’s modulus of 0.78 MPa, and significant notch insensitivity and fatigue resistance (the maximum stress retention rate is 83.6% after 50 stretching cycles), good water retention, and stable swelling structural integrity. In addition, dynamic ionic cross-linking also endows the hydrogel with a certain degree of self-healing ability. By combining the advantages of natural polysaccharides (KGM) and synthetic polymers, this study proposes an efficient method for preparing high-performance double-network hydrogels, providing a theoretical foundation and technical support for their application in oilfield profile control and water plugging.
Zhou et al. (Fri,) studied this question.