Synthesis of Ordered Packing Sheet‐Like C‐S‐H Structure Modified by Polyurethane

A novel approach has recently been uncovered to attain the ordered packing structure of sheet-like C-S-H, which is fabricating a polyurethane bonding and inserting the C-S-H structure at the nanoscale. The results disclose that nanosized sheet-like C-S-H gel forms a layered network, and both its chemical structure and morphology undergo changes. When the calcium-silicate ratio is set at 0.8 and the amount of PU employed is 0.3%, the degree of polymerization of the silicate chain increases. Specifically, the average chain length extends from 2.67 to 6.68. Computational analyses indicate that both the soft and hard components of PU contribute to enhancing the toughness of the PU intercalation-bonding C-S-H structure. When this new structure is incorporated into macro-defect-free cement, the flexural strength and compressive strength of the 3-day-cured MDF cement samples can reach 33.3 MPa and 88.0 MPa, respectively. This provides a new pathway for the development of advanced cement-based composites.