Using the Memory Effect of Layered Double Hydroxides to Prepare Superabsorbent Polymers (SAP) for Internal Curing in Concrete

Superabsorbent polymers (SAP) are emerging as promising materials for internal curing in concrete. However, the water absorption performance of most SAP in concrete is significantly affected by complex ionic environments. This study developed a novel method to fabricate SAP composites. Utilizing calcination‐exfoliation and structural memory effects, we synthesized acrylic acid‐intercalated layered double hydroxide (AA‐LDH), which was incorporated into P(AA‐co‐AM) copolymer to form a composite SAP with unique physicochemical structures. The study evaluated the SAP's water absorption performance, water retention, thermal stability, and desorption behavior under various conditions. The results show that the water absorption rate of the composite SAP added 1 wt% AA‐LDH in deionized water reached 618.2 g/g, which is 6.7% higher than that of the unmodified SAP. The water retention rate of the composite SAP is significantly improved, and the highest is 92.5%. The addition of AA‐LDH improves the thermal stability of the SAP. Specifically, AA‐LDH can effectively inhibit the thermal decomposition of the molecular chain of the SAP above 400°C. These enhanced physicochemical properties enable the SAP to better adapt to the concrete environment.