Utilization of oleic acid in synthesis of epoxidized soybean oil based green polyurethane coating and its comparative study with petrochemical based polyurethane

摘要

Epoxidation of soybean oil (ESBO) was carried out using Amberlyst 15 catalyst followed by ring opening using bio-based oleic acid to yield polyester polyol (ESOAP). Polyurethane (PU) coating was prepared by utilizing synthesized polyester polyol with hexamethylene diisocyanate (HDI) in the presence of dipentene as a green solvent. To meet industrial standards, biobased polyurethane coatings (Bio-PU) must match the performance of petroleum based polyurethane (Petro-PU) and hence a comparative study is carried out between synthesized bio based polyurethane coating and a petroleum based polyurethane coating. The characterization techniques like Fourier-transform infrared spectroscopy (FT-IR) and Nuclear magnetic resonance (NMR) used for structural elucidation of epoxidized soybean oil and polyester polyol. The cured Bio-PU coating shows good optical and mechanical properties compared to Petro-PU coating. Differential scanning calorimetry (DSC) and Thermo gravimetric analysis (TGA) analysis were carried out to analyse the glass transition temperature (Tg) and thermal stability of the PU coatings. The Electrochemical impendence spectroscopy (EIS) study revealed that the Bio-PU coating exhibited high corrosion resistance (1.23 x 10(7)) against Petro- PU coating. The bio-based content of synthesized polyurethane was calculated to 88.43%. The contribution of oleic acid grants a novel approach to this scheme along with making the end application of coatings more environment friendly.