Synthesis and characterization of Luffa cylindrica fatty acids-based alkyd resins

The work reports on preparation of three grades of alkyd resins using a two-stage alcoholysis-polyesterification method. Phthalic anhydride, glycerol and Luffa cylindrica seed oil were used in the formulation of the alkyds. The oil was extracted with n-hexane and 30.30 % was obtained. The fatty acids and physicochemical analyses of L. cylindrica seed oil revealed 77.78 % unsaturated fatty acids with linoleic acid (50.25 %), oleic acid (27.30 %), palmitic acid (13.40 %), and stearic acid (6.38 %) being the most abundant; and iodine value, 153 mg I₂/g respectively. Properties of the alkyds having oil content of 40 % (I), 50 % (II) and 60 % (III) were evaluated. The acid value was observed to decrease as the reaction progressed. FTIR spectra of the alkyds revealed ester linkages and olefenic hydrogen stretch at 1737.92-1734.06 and 3064.99-3007.12 cm^-1 respectively. Evaluation of prepared alkyds by determination of acid values, iodine values, solubility in xylene, toluene and acetone; resistance of dry film to acid, alkali and water; scratch and gouge film hardness and drying time revealed that L. cylindrica seed oil is a potential raw material for the coatings industry.