Studies on the preparation and properties of biodegradable polyester from soybean oil

Crude dimer acid (DA) was prepared with soybean oil (SO) used as raw material and organic montmorillonite as a catalyst. Fourier transform infrared (FTIR) spectroscopy, hydrogen nuclear magnetic resonance (1H-NMR) and gel permeation chromatography (GPC) were used to characterize the structure of DA. It was demonstrated that the synthesis of crude DA using SO was feasible. A molecular weight of 995–1304 g/mol was obtained by GPC measurement. Then, a type of polyester was synthesized using the crude DA and polyethylene glycol. The effects of reaction temperatures and different catalysts on the conversion rate were explored. The results showed that the esterification conversion rate was improved to 83.13% when SnCl2 was used as the catalyst, with a reaction temperature of 180°C The FTIR, 1H-NMR, GPC and TGA were used to characterize the structure and performance of this polyester. The polyester had a molecular weight ranging from 8259 to 10892 g/mol. In addition, its biodegradable behavior was analyzed by the soil burial test and was compared with that of terephthalic acid. The results showed that the composites prepared from DA had a pronounced effect on weight loss during biodegradation