Synthesis and characterization of palm oleic acid based polyester for bioplastic applications

Abstract

Oleic acid (OA) is a monounsaturated fatty acid and natural constituent of a number of foods, particularly plant oils. In this work, palm OA epoxidation was performed using formic acid and hydrogen peroxide. The epoxidation of OA showed that the relative conversion of oxirane oxygen (RCO) 97.4% with 85.3 % yield. The FTIR spectrum of epoxide oleic acid (EOA) clearly showed the signals at 1701 and 845 cm -1 attributed to C=O (carboxylic acid) and oxirane ring groups, respectively. The 1 H and 13 C NMR analysis showed the chemical shift of (-CH-O-CH-) group at 2.93 and the 54.30-57.40 ppm, respectively, for EOA. The bioplastic polyester was prepared from EOA as monomer through the polycondensation polymerization at 120 °C with different polymerization times (6, 12, 18, 24 and 30 hr). The synthesized bioplastic polyester showed about 97 % yield. The FTIR spectra showed the peaks of C=O and C-O of ester carbonyl group appeared at 1735 cm -1 and 1244 cm -1 respectively. The 1 H NMR showed the proton ester group -COO-CH- an appeared at 4.7 ppm while the 13 C NMR showed C=O ester appeared at 173.79 ppm. The molecular weights of bioplastic polyester were between 1963 g/mol to 5501 g/mol and having a glass transition of -19 °C. The thermal degradations of the bioplastic polyester occurred at temperatures higher than 328 °C. The synthesized bioplastic is plausible to be used as plastic wrapping material.