Elastomer-modified perfluorocyclobutyl polymer/SiO2 composites for corrosion-resistant coatings

Abstract

This study investigates the development of elastomer-modified perfluorocyclobutyl (E-PFCB) thermosetting polymer composites containing polydimethylsiloxane (PDMS)-modified silica as nanofiller and exhibiting enhanced corrosion protection. Electrochemical impedance spectroscopy results revealed that the incorporation of silica significantly improved the composites' corrosion resistance, with an impedance modulus (|Z|_0.1 Hz) for the PFCB/silica composite containing 5 % silica remaining above 10⁶ Ω cm² even over 30 d of immersion in a 3.5 wt% NaCl solution. This demonstrates the composite's superior ability to resist water uptake and electrolyte penetration. Potentiodynamic polarization scans showed a notable shift in corrosion potential from −700.2 mV for the unfilled E-PFCB to −101.1 mV for the 5 % silica composite, indicating lowered tendency for corrosion. Mechanical testing further confirmed the improvements in the composites' properties, with hardness values increasing as silica loading increased. The 5 % silica composite showed the highest hardness, reflecting the enhanced durability imparted by the silica particles. Thermomechanical analysis revealed a shift in the glass transition temperature from 308 °C for the unfilled E-PFCB to 330 °C upon the addition of 5 % silica. In addition, water contact angle measurements confirmed the hydrophobic nature of the composites, with contact angles consistently above 90°, further limiting water interaction and corrosion risk. Hence, the use of PDMS-modified silica as a nanofiller in crosslinked E-PFCB composites significantly enhances both corrosion resistance and thermomechanical properties, making these composites suitable for applications in harsh environments. These findings open up opportunities for the development of new and advanced protective coatings for many practical applications.