Properties of polyurethane coatings based on linseed oil phosphate ester polyol

Abstract

Linseed oil was epoxidized using hydrogen peroxide (H2O2), acetic acid (AcOH) and ion exchange resin Amberlite IR-120 as a catalyst. Epoxidized oil was separately dissolved in isopropyl alcohol (IPA) or diethylene glycol butyl ether (DGBE) and phosphorylated with different amounts of phosphoric (H3PO4) acid (1%, 2%, 3% and 5%). The formation of phosphate polyesters was confirmed by Fourier-transform infrared (FTIR) and31P nuclear magnetic resonance (NMR) spectra. Based on the synthesized polyols, polyurethane (PU) coatings were prepared. PU coating based on linseed oil diethylene glycol ester polyol was used as the reference. For the characterization of coatings, mechanical tests and thermogravimetric analysis (TGA) were used. The flammability parameters of wood samples with PU coatings at a heat flux of 35 kW/m2 were determined. It was found that PU coatings based on IPA polyols had higher mechanical characteristics, char residue upon thermal decomposition and flame retardancy.