Solvent-free preparation of bio-based composite coating with improved crystallinity and unique corrosion resistance

Abstract

Bio-based materials have garnered considerable attention in the context of the “two‑carbon” strategy. However, the unsatisfactory barrier properties and hydrophobicity have affected their application in the field of metal protection. In this work, a poly(lactic acid) (PLA) /poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer (PHBV) biocomposite coating (80A/20B) with perfect anti-corrosion performance was successfully prepared employing hot pressing method. In addition, the addition of perfluorooctane triethoxysilane modified talc (talc-POTs) to 80A20B further improves the crystallinity and compactness of the composite, thereby significantly enhancing the barrier properties, impermeability and corrosion resistance of the composite coating. EIS tests demonstrate that the low-frequency impedance of the 5Talc-POTs/80A20B coating maintained above 1011 Ω·cm2 after 90 days of immersion in 3.5 wt% NaCl solution. More significantly, in contrast to previous reports, the 5Talc-POTs/80A20B biocomposite coating has a broad potential for application due to its preferable antiseptic property and green preparation technology (no VOCs emission).