On the curing of linseed oil epoxidized methyl esters with different cyclic dicarboxylic anhydrides

Methods for obtaining epoxidized linseed oil methyl esters and curing them with phthalic (PA), cis-1,2,3,6-tetrahydrophthalic (THPA) and cis-1,2-cyclohexanedicarboxylic (CH) anhydrides in the presence of 2-methylimidazole as initiator/catalyst are presented. The methodology employed for the characterization includes lH and 13C NMR and FTIR spectroscopy. The curing processes were evaluated by non-isothermal differential scanning calorimetry (DSC) to evaluate the reaction mixture molar compositions and types of dicarboxylic anhydrides. The optimum conditions for curing were determined. The experimentally obtained enthalpies per epoxy group-equivalent are 37.9 kJ/ee for PA, 46.8 kJ/ee for THPA and 51 kJ/ee for CH. The average activation energies were obtained by using the Kissinger, Osawa, Samios and Barrett standard techniques.