Oligoesters and polyesters produced by the curing of sunflower oil epoxidized biodiesel with cis-cyclohexane dicarboxylic anhydride: Synthesis and characterization

Abstract

Oligoesters and polyesters produced from sunflower oil biodiesel were synthesized and characterized. The polymers were obtained through the reaction of fatty acid methyl epoxy esters (EE) with cis-1,2-cyclohexane dicarboxylic anhydride (CH) and triethylamine (TEA) as initiator. Some reactions were conducted by adding small amounts of 1,4-butanediol diglycidyl ether (BDGE). The intermediate products of the synthesis process, including sunflower oil, methyl ester, epoxidised methyl esters, and the oligoesters and polyesters produced, were followed by Fourier Transform Infrared Spectroscopy and 1H and 13C nuclear magnetic resonance. The products obtained from the curing of the epoxidised esters with different compositions present similar chemical structures; however, they still depend on the amount of the epoxy resin BDGE that was added in the polymerization reaction. Thermoplastic materials with molecular weights (MW) starting at 3800 g/mol and reaching very high MWs, resulted in cross linked polymers. The thermal behaviour of the different products was investigated using differential scanning calorimetry and thermogravimetric analyses. The presence of BDGE in the structure of the materials increases the bonding capacity, resulting in higher molecular weight materials, which present good thermal stability.