Adhesion aspects of levulinic-acid-modified furan polymers to crystalline zinc phosphate metal surfaces

Abstract

SynopsisThe nature of the interfacial interactions between functional levulinic-acid-modified furan resin coatings and crystalline zinc phosphate hydrate films deposited on carbon steel surfaces has been systematically investigated. The typical surface topography of the highly crystallized zinc phosphate films was found to be characterized by the presence of a dendritic microstructure array of interlocking triclinic crystals. This structure acts significantly to develop mechanical interlocking bonds with the functional blend polymer which penetrates into the open surface structure of the films. Both the thickness of deposition film and the polar HzO molecules of hydrate at the outermost film surface sites play essential roles in wetting by the functional liquid resin. When the polarized furan polymers spread on the oxide film surfaces, the carboxylate groups derived from the levulinic ester and acid molecules react to form strong hydrogen bonds with the crystallized HzO molecules on the hopeite film. This formation of hydrogen bonding was shown to be a major factor affecting the chemical intermolecular attractions. A formulation consisting of 95 parts furan to 5 parts levulinic acid was found to yield the optimum protective coating. More than 5 parts levulinic acid resulted in the transformation of the characteristics of the polymer film from hydrophobic to hydrophilic.

Furfuryl Alcohol Polymerization in H−Y Confined Spaces: Reaction Mechanism and Structure of Carbocationic Intermediates

“…This assignment supports the hypothesis that, during oligomerization, formation of diketonic structures is occurring, following Scheme 4. 15,38 (iii) The band at 1628 cm -1 is of problematic assignment. In fact, it could be ascribed to the bending mode of H 2 O coordinated to the sodium cations of the H-Y zeolite 39 (H 2 O molecules are formed during the condensation processes, as reported in Schemes 1 and 2) or to the ring stretching mode of the 2,3-bisubstituted furan rings, as suggested in ref 40, thus supporting the formation of branched species.…”

Investigation of the adhesion toughness of lacquer to zinc-phosphated steel

“…Sugama et al [9] have shown that adhesion strength decreases with increasing zinc phosphate thickness. Previous results with iron-phosphated coldrolled steel [16] have shown the appearance of microcracks in thicker films.…”

Adhesion of a rigid polyurethane foam to zinc phosphated steel

“…E-mail: jangskim @lgchem.com surface structure, important in the bonding of polymer coatings to metal substrates. The intrinsic adhesion observed at polymer/ zinc phosphate joints is attributed to a mechanical interlocking bond produced from polymer melt penetration into the open spaces and micro ssures of the phosphate coating [8,9]. This physical interlocking results in a much stronger bond than that produced with a smooth substrate surface.…”

“…The role of crystallization in adhesion in PEEK/zinc phosphated steel joints was not examined. In another study, carboxylate groups in furan polymer lms, derived from the levulinic ester and acid molecules, were found to form strong hydrogen bonds with the H 2 O molecules on a hopeite (Zn 3 (PO 4 ) 2 ¢ 4H 2 O) lm [9]. Also, Sugama et al [11] reported that the products of the reactions between amide groups in polyurethane coatings and carboxylic acid groups on the outermost surface of a polyelectrolytemodi ed zinc phosphate played an essential role in developing interfacial adhesion strength.…”