Preparation and physicochemical characterization of emulsion alkyd resins from cottonseed, Hura crepitans L. seed and palm kernel oils

Abstract

The growing environmental concerns have led to the formulation of new coating strategies by employing inherently waterborne binders as a key component in order to eliminate the toxic volatile organic solvents from protective coatings. Hura crepitans L. seed oil (HCSO) was extracted from the seed pulp via solvent extraction and characterized using standard methods. Cottonseed oil (COSO), palm kernel oil (PKO), and HCSO were used in the formulation of emulsion alkyd resins (EMAR) via a two-stage alcoholysis-polyesterification process followed by the introduction of maleic anhydride in the polymer backbone and neutralization of the free acid functionality with triethylamine (TEA). Three grades EMAR (50%) were prepared using these oils, phthalic anhydride, glycerol, and maleic anhydride. The percentage yield of HCSO was 87.93%. While the iodine and acid values of HCSO were 145.90 g I2/100 g and 1.26 mg KOH/g respectively. COSO emulsion alkyd (CWAR), HCSO emulsion alkyd (HWAR), and PKO emulsion alkyd (PWAR) were highly soluble in water, while the iodine value of 81.38 gI2/100g, 85.02 gI2/100g, and 10.45 gI2/100g was recorded for CWAR, HWAR, and PWAR respectively. The solid content of the binders varied between 84.88 – 85.48%. While the viscosity varied between 1756.00 – 1768.00 mpa.s. HCSO and COSO can serve as good starting raw materials for the synthesis of environmentally friendly waterborne alkyd resin.