Water Retention. The water retention capacity was determined under the condition of centrifugal separation (6000 rpm) and high-temperature drying (60 °C). The results are shown in Figure 3a, which indicates that the WR maintained 39 and 0.5% after centrifugation for 60 min and drying for 70 h, respectively. van der Waal’s forces and the hydrogen-bonding interaction between the superabsorbent and water molecules directly affected the water retention performance of the absorbent resin.33 The substantial carboxylate groups contained in MB−PAA made the chemical interaction stronger, which could improve the WR. From the centrifugation curve, it can be seen that in the first 20 min, the curve showed a sharp decline, whereas 20 min later, the water retention went down slowly. The reasons for this phenomenon were that, initially, more weak absorption water contained in the gel was more easily broken free, and with the passage of the centrifugation time, the relative proportion of strong absorption water increased, leading to a relatively slow dehydration. The drying curve showed similar properties, but the changes in the rate of water loss were not so obvious. This indicates that the water-absorbing resin was more sensitive to pressure than to temperature. The obtained good water absorbency and retention properties would allow for a further development of the material, such as in agricultural, forestry, and horticulture applications as a water-retaining agent in arid soils.