A polyesteramide from Pongamia glabra oil for biologically safe anticorrosive coating

Pongamia glabra is a widely grown tree in the coastal regions and elsewhere in India. The estimated annual production of oil from its seeds is about 50,000 t. The oil has not yet found any significant commercial application. In the present study attempt has been made to synthesize polyesteramide resin from R glabra seed oil (PGO) and use the former as anticorrosive coating material. Oil from P. glabra was extracted and characterized. It was first converted into N,N-bis(2-hydroxyethyl) R glabra fatty amide (HEPGA), which was further transformed into polyesteramide (PGPEA, P. glabra polyesteramide) by reacting with the phthalic acid. Characterization of PGPEA resin was carried out by Fr-IR, H-1 NMR, DSC, TGA and other chemical tests. The coatings of PGPEA resin were obtained on mild steel strips. The coatings can be cured between 185 and 250 degreesC. The best temperature and time for curing were obtained as 210 degreesC and 20 min. Physico-mechanical properties of PGPEA coatings were found to be superior to the reported polyesteramide coatings; however, its anticorrosive properties were found comparable with the reported high performance polyesteramides. The nature and amount of unsaturation in the fatty acid chain as well as its conversion into the cross-links all were found to influence the physico-mechanical and anticorrosive properties. The toxicity evaluation and skin irritation tests of HEPGA and PGPEA have shown that these materials are biologically safe for industrial application. (C) 2003 Elsevier B.V All rights reserved.