Effect of karawila (Momordica charantia) seed oil on synthesizing the alkyd resins based on soya bean (Glycine max) oil

Air drying long oil alkyd resins of 65% oil length were synthesized from a blend of soya bean (Glycine max) oil and karawila (Momordica charantia) seed oil. Different proportions of karawila seed oil (w/w% 10, 20, 30, 40 and 50) were blended with soya bean oil to examine the effect of karawila seed oil on the drying behavior of alkyds synthesized from soya bean oil. A sharp variation of viscosity is only observed for alkyd resins having more than 40% (w/w) of karawila seed oil. The polyesterification time was reduced and correspondingly the extent of polymerization was also reduced up to 30% (w/w). Significant variation in transesterification time was also observed for 30% (w/w). However, further increase in karawila seed oil above 40% (w/w) had only a marginal effect on the polyesterification reaction. The drying properties of the alkyd resins had been significantly improved with the increase of karawila seed oil up to 30% (w/w) but further increase in karawila seed oil resulted in poor drying characteristics. The film properties (drying time, hardness, adhesion, chemical resistance and gloss) of the alkyd resins were determined. The optimum film properties were recorded for the oil blend with 30% (w/w) karawila seed oil and 70% (w/w) soya bean oil.

► We examined the effect of karawila seed oil on soya bean oil based alkyd resins. ► Viscosity of alkyd resins increased significantly after increasing karawila seed oil above 40%. ► Both polyesterification time of reaction and drying time of alkyds had significantly dropped. ► Optimum film properties were observed for alkyd resins with 30% (w/w) karawila seed oil in oil blend.