posted on 2024-03-11, 18:06authored byKaren
Y. Patiño Jaimes, Eugene B. Caldona, Ellis M. Kim, James Lambert, Evelyn C. Winn, Erick L. Ribeiro, Yijie Jiang, Sanjida Ferdousi, Blake Hicks, Yangyang Wang, Ilia N. Ivanov, Rigoberto C. Advincula
Compared to other polymers, composite coatings with fluoropolymers
as the matrix have attracted considerable interest due to their mechanical
performance, chemical stability, and low surface energy. Herein, we
present an anticorrosion mechanism of fluoropolymer composite coatings
achieved by dispersing varying amounts of polyamide 12 (PA-12) particles
over a poly(vinylidene fluoride-co-hexafluoropropylene)
(PVDF-HFP) matrix. The choice of PVDF-HFP as a coating matrix was
driven by its superior processability and mechanical properties over
Teflon, while PA-12 afforded swelling capacity, preventing electrolyte
permeation, and inhibiting matrix stress crack propagation. The corrosion
resistance of the coatings was assessed mainly by potentiodynamic
polarization and impedance measurements while being immersed in a
NaCl solution. Our electrochemical measurement findings showed that
0.75% w/w PA-12 in the PVDF-HFP matrix significantly enhanced corrosion
protection even after 21 days of immersion. Microscopy, dielectric
spectroscopy, surface analysis, and mechanical testing (American Society
for Testing and Materials standards) corroborated the results. PVDF-HFP
coatings containing a minimum percolation threshold of 0.75 wt % PA-12
with 1 mil thickness on mild steel exhibited a remarkable increase
in resistance and film adhesion, and a notable corrosion rate decrease.
Finite element analysis simulation with a bilinear traction-separation
law confirmed the swelling mechanism and adhesion behavior. This study
highlights the potential of nylon particle dispersion in PVDF-HFP
matrices as a practical approach to developing advanced anticorrosion
coatings with promising practical applications in various industries.