High-Performance Cement Composites Achieved by Synergistic Modification of In-Situ Polymerized AM and Gelatinized OS for Interpenetrating Polymer-Cement Networks

Polymer modification has demonstrated effectiveness in improving fracture resistance and mitigating brittleness in cement-based materials. However, conventional modification methods result in compromised strength or an imbalance in mechanical properties. This study develops an innovative dual-network modification strategy through the synergistic combination of in-situ acrylamide (AM) polymerization and oxidized starch (OS) gelatinization in cement-based materials. The gelatinized OS forms a homogeneous framework that regulates moisture, while the in-situ formed polyacrylamide (PAM) interacts with it to create an interpenetrating network. This unique structure refines the polymer morphology and enhances the interface with cement hydrates. The resulting composite demonstrates a 103% increase in 28-day flexural strength compared to plain cement. Furthermore, the composite maintains superior performance over both in-situ polymerization-modified specimens and conventional polymer-modified systems, retaining 12% higher 28-day flexural strength and 19% greater compressive strength than AM in-situ polymerization modified samples. Microstructural analysis indicates that the approach optimizes hydration and promotes stress redistribution. This work suggests that controlled dual-network interpenetration offers a promising pathway to mitigate the traditional strength-toughness trade-off in cement-polymer composites.