Modification of poly(vinyl butyral) coatings using bis-silanes

A commercially available poly(vinyl butyral) (PVB) coating was modified using a combination of 1–10 wt.% bis(trimethoxysilylethyl)benzene and dibutyltin dilaurate as the hydrolysis catalyst. Results of attenuated total reflectance (ATR)–FTIR analysis indicated the modification resulted in a hybrid coating material containing silicate moieties covalently bonded to the PVB polymer chains. Gravimetric analysis indicted the bis-silane addition resulted in a reduction in the diffusion coefficient of the parent coating to 2-chloroethyl ethyl sulfide (2-CEES), dimethyl methylphosphonate (DMMP), diisopropyl methylphosphonate, and methyl salicylate; the most significant reduction was observed for 2-CEES and DMMP at temperatures ≥50 °C. Glass transition temperature, abrasion resistance, tensile strength, and coating hardness were increased upon incorporation of the bis-silane. Despite incorporation of an inorganic component, coating flexibility was retained at low temperature (−15 °C).