Preparation and Properties of Double Network Hydrogel with High Compressive Strength.

In this work, p-double network (p-DN) hydrogels were formed by the interpenetration of poly(2-acrylamide-2-methylpropanesulfonic acid-copolymer- acrylamide) microgel and polyacrylamide. The initial viscosity of prepolymer solution before hydrogel polymerization, mechanical properties, temperature and salt resistance of the hydrogels were studied. The results showed that the initial viscosity of the prepolymer was less than 30 mP·s, and the p-DN hydrogel not only exhibited high compressive stress (37.80 MPa), but the compressive strength of p-DN hydrogel could also reach 23.45 MPa after heating at 90 °C, and the compressive strength of p-DN hydrogel could reach 13.32 MPa after soaking for 24 h in the solution of 5W mineralization. In addition, the cyclic loading behavior of hydrogel was studied. The dissipation energy of p-DN hydrogel under 80% strain was 7.89 MJ/m, which effectively dissipated energy. Meanwhile, p-DN hydrogel maintained its original form while breaking the pressure greater than 30 MPa, indicating excellent plugging performance.