Polyurethane/Polysiloxane Ceramer Coatings: Evaluation of Corrosion Protection

• Published in: Macromolecular materials and engineering Vol. 287; no. 7; pp. 470 - 479
• Main Authors: Ni, Hai, Johnson, Aaron H., Soucek, Mark D., Grant, John T., Vreugdenhil, Andrew J.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.07.2002; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; coatings; Composites; Corrosion; Corrosion prevention; Exact sciences and technology; Forms of application and semi-finished materials; hybrid; Metals. Metallurgy; Polymer industry, paints, wood; polysiloxanes; polyurethanes; Technology of polymers; Corrosion protective layer; Coating material; Solid solid interface; Hybrid material; Aluminium; Triazine derivative polymer; Experimental study; Corrosion protection; Polyaddition; Mechanism; Interface structure; Esterurethane polymer; Sol gel process; Silicon oxides; Preparation; Crosslinked polymer; Silicon polymer
• ISSN: 1438-7492; 1439-2054
• DOI: 10.1002/1439-2054(20020701)287:7<470::AID-MAME470>3.0.CO;2-D

A series of polyurea and polyurethane ceramer coatings were formulated using hexamethylene diisocyanate (HDI) isocyanurate, alkoxysilane‐functionalized HDI isocyanurate, tetraethyl orthosilicate (TEOS) oligomers and cycloaliphatic polyesters. The coatings were prepared as a function of alkoxysilane‐functionalized HDI isocyanurate and TEOS oligomers concentration. Also, the effect of acid catalyst was investigated. The corrosion resistance of polyurea or polyurethane ceramer coating systems were evaluated using a prohesion chamber on aluminium alloy 2024‐T3 substrate. The polyurethane ceramer coatings were compared with the chromate pretreatment and the epoxy‐polyamide primer containing the chromate pigment. In addition to prohesion, the interface between the coating and substrate was characterized using X‐ray photoelectron spectroscopy (XPS). The prohesion data showed that the corrosion was inhibited by the TEOS oligomers. However, high concentrations of TEOS oligomers and acid catalyst produced blistering in the polyurea/polysiloxane ceramer coatings. The prohesion data also showed that the corrosion protection of ceramer coatings performed as well as the chromate pretreatment and competitively with the epoxy primer. From the XPS and prohesion data, a self assembling silicon oxide layer at the metal‐coating interface was proposed.