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| Reason Analysis on Peel-off between Mica Iron Oxide(MIO) Epoxy and Polyurethane Layer |
| Received:February 09, 2016 Revised:August 15, 2016 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7643/ issn.1672-9242.2016.04.023 |
| KeyWord:PUFC epoxy mica iron interface adhesion micro pores of coating |
| Author | Institution |
| SHEN Zhi-cong |
Corrosion Science and Technology Institute of Minhang District, Shanghai , China |
| YANG Hua |
×××Assembly Engineering Command Department, Wengchang , China |
| SHI Wen-ming |
Shanghai Huneng Anticorrosion and Insulation Engineering Co, Ltd., Shanghai , China |
| WU Xian-guan |
Corrosion Science and Technology Institute of Minhang District, Shanghai , China |
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| Abstract: |
| Objective To analyze the reason why polyurethane peels off from epoxy micaceous iron oxide layer in a big coastal steel structure project. Methods The composition of PUFC was analyzed using MS, amino salt on coating surface was detected using ion chromatograph and conductivity meter, and the release coating surface was observed using environmental scanning electron microscope. Results Polyurethane coatings contained high boiling solvents trimethylbenzene and tetramethylbenzene; ammonium salt substance existed on the interface between polyurethane coating and fluorocarbon composite epoxy mica iron oxide; Through the microscopic observation of the electron microscope, the existence of the incomplete and micro pores in the coating was found. Conclusion The causes for peeling off of polyurethane fluorocarbon coating might be explained as the following. Micro pores were formed in the coating because polyurethane coatings contained high boiling solvent. Epoxy mica iron and H2O and CO2 in air reacted to generate carbamate due to the slow curing reaction of epoxy resin at low temperature. Carbamate formed an aqueous solution in marine environment, which was enriched at the adhesive interface of epoxy micaceous iron oxide coating and polyurethane coating, reducing the adhesion and further decreasing the phase interfacial adhesion, leading to severe peelability of polyurethane fluorocarbon coating. |
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