Synthesis of a Multi‐Armed Hydrazide‐ <scp>POSS</scp> and Its Enhancement on the Salt and Thermal Resistance of Hydrophobically Associated Polymers

ABSTRACT The viscosity and elasticity of water‐soluble polymers are critical in the petroleum industry, particularly under high‐temperature and high‐salinity conditions. In this study, a multi‐armed hydrazide‐POSS (HPOSS) and a carbonyl‐functionalized hydrophobic association polymer (CFHAP) were developed to create dual networks (CFHAP/HPOSS). Unlike conventional binary cross‐linkers, HPOSS promoted the formation of dense and stable covalent cross‐linked structures. Even at low concentrations of both CFHAP and HPOSS, CFHAP/HPOSS exhibited robust network formation with exceptional thickening properties, achieving a significantly higher viscosity of 3927 mPa·s at 2 g/L compared to the polymer's 410 mPa s and the binary cross‐linking system's 2453 mPa s. Under a 40 g/L Na + solution, CFHAP/HPOSS exhibited salt responsiveness by enhancing their hydrophobic network, resulting in a viscosity of 5325 mPa s and a modulus G′ &gt; G″. These enhanced rheological properties were further utilized to improve aqueous foam stability. The results revealed improved foam stability with an extended half‐life time (8248 s), low drainage rate (0.0064 g/s maximum), and minimal bubble size distribution variation. SEM images also reveal a fully formed polymer film network, which effectively inhibits foam drainage and coarsening. Our strategy provides valuable insights into developing new materials with adjustable thickening and elastic properties.