A Study on Aqueous Polymer‐Modified Aluminum Sol‐Based High‐Temperature Putty for Extreme Environments

ABSTRACT Three types of waterborne polymers, including polyvinyl alcohol, single‐component waterborne epoxy, and two‐component waterborne epoxy, were incorporated as organic modifiers to fabricate aluminum sol‐based organic–inorganic hybrid high‐temperature repair putties with nano‐alumina fillers. Comparative characterization results reveal that the two‐component epoxy‐modified system exhibits the most balanced overall performance, and an optimal formulation designated as AEA‐2 containing 10 wt% two‐component epoxy was identified. The AEA‐2 sample achieves a room‐temperature shear strength of 2.86 MPa. After thermal treatment at 1000°C, no obvious cracking or spalling defects are observed on the AEA‐2 putty layer. Thermogravimetric analysis demonstrates a high residual mass fraction during high‐temperature exposure. The formation of an organic–inorganic interpenetrating network through covalent crosslinking and hydrogen bonding interactions is proposed to contribute to enhanced thermal stress relaxation. This work provides insights into the design of aluminum sol‐based high‐temperature repair putties for extreme thermal environments.