Development of new bio-based polyol ester from palm oil for potential polymeric drug carrier

Abstract

The polyol ester derived from palm oil polymers is a promising material for utilizing it as a polymeric drug carrier due to its natural and biocompatible properties. In this study, the palm oil-based diol is used as a precursor for developing the polyol ester via the transesterification-alcoholysis reaction of the diol with triethanolamine and lithium hydroxide. Preliminary results showed that the polyol ester displayed high hydroxyl value at 182.51 mg KOH/g with the yield reached more than 90%. Meanwhile, its molecular weight was around 5,000 Dalton. The appearances of ester (C–O) between 1,300 and 1,000 cm−1 in the Fourier transform infrared (FTIR) spectra have confirmed the hydrolyzable ester structure of the polyol ester. Consequently, the δH- and δC-NMR spectra also confirmed the presences of the ester proton (i.e., -COO–CH2-) and the ester carbons (i.e., -CH2CH2CO(O)C-, -CH2COO-, -CH2C(O)OC-). Thermogravimetric analysis of the polyol ester displayed three stages of maximum decomposition temperature (Tmax): 203.56°C, 362.79°C, and 481.91°C. Differential scanning chromatography (DSC) analysis indicated that the glass transition temperature (Tg) of the polyol ester was found between −3.27 and 7.5°C. As a result, the analyses affirmed that this polyol ester is a hydrolytically degradable polymer due to the presence of its hydrolyzable ester bonds. Its low molecular weight and low-melting biodegradable properties could show a faster degradation compared to the higher molecular weight synthetic polymers. Thus, the characteristic of the developed polyol ester demonstrates promising physicochemical and good thermal properties, which makes it a potential candidate for a polymeric drug delivery system.