Synthesis of fast drying long oil alkyd resins using seed oil of Karawila (Momordica charantia)

Abstract

Seed oil of the agricultural variety, Momordica charantia (MC43) cultivated in Sri Lanka, has been used to synthesize long oil length (65%) air drying alkyd resins by monoglyceride process. Esterification reactions were continued until the resins were about to gel. Final acid values are found to be close to 10 mg g^-1 with high extent of polymerization values, mostly above 0.95. Alkyd resins of Seed Oil of MC43 are found to have fast drying characteristic, mainly due to the presence of 56.59% of eleostearic acid. Unlike for tung oil (80% of eleostearic acid), the risk of gelation for seed oil of MC43 is found to be less significant. Glycerol improves the extent of polymerization but imparted poor film properties. Good film properties have been achieved with a minimum molar ratio, 0.45, of pentaerythritol to seed oil of MC43.