Synthesis and antibacterial activity of waterborn polyurethane containing quaternized silica

Abstract

Silica was prepared from sodium silicate by reacting with acetic acid. Its surface was firstly modified by coupling with 3-aminopropyltriethoxysilane (APTES) and further reacted with 3-chloro-2-hydroxyltrimethyl ammonium chloride to obtain quaternized silica. Polyurethane prepolymer was then generated from polyester polyol, isophoronediisocyanate and dimethylolpropionic acid. APTES was added to polyurethane prepolymer prior to the addition of the as-prepared quaternized silica. The quaternized silica content was varied. Waterborne polyurethane was then produced by self-emulsification method in which an oil phase containing NCO-terminated prepolymer, the catalyst dibutyltin dilaurate, the crosslinking agent triethyl amine (TEA) and the chain extender ethylene diamine (EDA), was dispersed in the water phase. All the products were characterized by FTIR, ¹³C NMR and 29Si NMR spectroscopy and TEM. The antibacterial activity of quaternized silica and water polyurethane containing quaternized silica against Escherichia coli and Staphylococcus aureus was examined by the suspension quantitative method. The waterborne polyurethane containing quaternized silica showed good thermal stability and mechanical property.