A rigid and flexible combination 3D network with hyperbranched materials as bridge and the enhancement of mass transfer resistance in coatings

Defects formed during the curing process of epoxy resin coatings can compromise their shielding efficacy, necessitating mitigation strategies to preserve functional performance. This study introduces a multiscale composite filler (PHL) employing hyperbranched polymers to integrate flexible polymeric chains with rigid inorganic particulates. A three-dimensional network structure was constructed within the coating by bridging flexible polyamide and rigid rod-shaped lanthanum oxide with resin using hyperbranched materials. Following the reaction between PHL and epoxy resin at 160 °C, they rapidly settle in solution, demonstrating the successful construction of the three-dimensional network structure of PHL resin. The 35 % PHL epoxy coating exhibited a low-frequency impedance of 10⁹ Ω·cm² after 48 h exposure to high-temperature/high-pressure CO₂ environments. This indicates that the addition of PHL increases the mass transfer resistance of the corrosive medium in the coating, and the coating has high shielding performance under high-pressure and harsh conditions. Notably, the wear resistance and adhesion of 35 % PHL epoxy coating are improved by 100 % and 50 % respectively compared to pure epoxy coating. These results establish that the incorporation of PHL composite filler enhances both shielding performance and mechanical performance in epoxy coatings. This study proposes an innovative methodology for combining multi-scale, rigid and flexible opposite materials and establishing a three-dimensional network structure in the resin matrix, hoping to provide a valuable theoretical basis and scientific evidence for the construction of protective coating structures in harsh environments.