Why does Silane Enhance the Protective Properties of Epoxy Films?

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• 作者：Peng Wang ; Dale W. Schaefer
• 刊名：Langmuir
• 出版年：2008
• 出版时间：December 2, 2008
• 年：2008
• 卷：24
• 期：23
• 页码：13496-13501
• 全文大小：444K
• 年卷期：v.24,no.23(December 2, 2008)
• ISSN：1520-5827

文摘

Using neutron reflectivity, the protection mechanisms of a novel one-step epoxy−silane coating system were investigated in terms of coating structure and water response behavior. By comparing pure epoxy and epoxy−silane mixtures in various aqueous environments, the effects of the addition of silane were determined. Specifically, a bridged bis-silane coupling agent with six alkoxy moieties and a polysulfur bridge was investigated. The key mechanisms of silane-enhanced protection are (1) the silane is enriched at the substrate-coating interface, forming a hydrophobic dense interfacial layer and good adhesion to the substrate, and (2) the silane serves as a cross-linker, resulting in a denser and less hydrophilic bulk film compared to the neat epoxy. The hydrophobic nature of bis-sulfur silane also increases the overall hydrophobicity of the mixed film.