Synthesis of polyesteramide resin from lower purity dimer acid and ethanolamine and its utilization as hardener for epoxy resinAuthor(s): Pravin G.Kadam, Shashank T.Mhaske
Polyesteramide (PEA) resin was synthesized using lower purity dimer acid (Pripol 1017, composition: 22%trimer acid, 75%dimer acid and 3%linoleic acid) and ethanolamine.Molar ratio of Pripol 1017: ethanolamine was varied as 1:1, 1:1.5 and 1:2. Prepared PEAs were characterized for acid value, amine value, hydroxyl value, Fourier transform infrared spectroscopy, gel permeation chromatography (number averagemolecularweight (Mn),weight average molecular weight (Mw) and polydispersity index (PDI)) and rheological (viscosity vs shear rate) properties. It was determined that amine value and hydroxyl values increased, whereas, acid value, Mn, Mw, PDI and viscosity decreased with increased molar concentration of ethanolamine in the PEA. Prepared PEAs were used as hardener for epoxy resin as a partial replacement for triethylenetetraamine (TETA), to prepare epoxy sheets. PEAs were added as 5%replacement of TETA. Cross-linked epoxy sheets were characterized for mechanical and thermal properties. It was found that tensile strength remained near about constant, YoungÂs modulus and degradation temperature decreased; whereas elongation at break increased with addition of PEAin epoxy as 5%replacement of TETA.Addition of PEA, thus helps in improving the flexibility of epoxy.