High performance polyurea coatings based on cardanol
Several phenalkamines were synthesised by conventional Mannich reaction; selecting various structural amines such as hexamethylene diamine (HMDA), isophorone diamine (IPDA), diaminodiphenyl methane (DDM), Jeffamine D-400 and Jeffamine T-403. Structures of these phenalkamines were confirmed by FTIR, 1H NMR spectroscopy and evaluation of amine value.
Improvement in anticorrosive performance
The curing agents were mixed with HDI and IPDI based blocked polyisocyanates to obtain polyurea coatings which were subsequently characterised for mechanical, chemical, optical, thermal and anticorrosive properties. In addition, structure property relationship of all the systems was studied and compared with commercial phenalkamine (AG-141). Anticorrosive properties evaluated by salt spray test and electrochemical impedance spectroscopy (EIS) revealed significant improvement in anticorrosive performance when compared with commercial phenalkamine. All polyurea coatings exhibited excellent performance properties irrespective of the isocyanates used.
The study is published in: Progress in Organic Coatings, Volume 106, May 2017, Pages 96–110