Study on Preparation and Performance of Low Water Absorption Thermal Insulation Coating Using Aluminate Coupling Agent‐Modified Hollow Glass Microspheres

ABSTRACT This study addresses the critical deterioration of thermal efficiency, mechanical properties, adhesion strength, and corrosion resistance in waterborne insulation coatings (WICs) caused by excessive water absorption. Systematic immersion‐aging tests revealed that heightened hydrophilicity originates from synergistic effects between hydrophilic film‐forming polymers and interfacial defects at filler‐matrix boundaries. A dual modification strategy was developed: polymer hybridization effectively reduced the resin's inherent water absorption, while surface modification of hollow glass microspheres (HGMs) with aluminate coupling agent (ACA) enhanced interfacial compatibility. Optimal loading of 30 wt% modified HGMs was determined through performance benchmarking, accompanied by rheological additive optimization ensuring exceptional storage stability. Custom‐designed thermal barrier evaluations demonstrated sustained insulation capability and long‐term thermal stability, validating the coating's durability. This work establishes systematic material design principles for high‐performance WICs, providing a technically viable solution for industrial applications requiring balanced thermal resistance and environmental durability.