Facile Synthesis of Biobased Polyamide Derived from Epoxidized Soybean Oil as a High-Efficiency Triboelectric Nanogenerator

A biobased thermosetting polyamide has been synthesized through the crosslinking of epoxidized soybean oil (ESO) with hexamethylenediamine (HMDA) for application in sustainable energy harvesting devices, triboelectric nanogenerators (TENGs). A simple synthetic method requiring neither a solvent nor catalysts was employed. Amide formation was confirmed by FTIR signals corresponding to C═O stretching at ∼1650 cm–1, N–H bending vibration at ∼1540 cm–1, and C–N stretching at 1168 cm–1. Polyamides of ESO/HMDA demonstrated excellent thermal stability (displaying a DTG peak at around 460 °C), high hydrophobicity with a water uptake of lower than 1.5%, and contact angles in the range of 86–120°. Importantly, the ESO/HMDA TENG exhibited outstanding electrical performance compared to other biobased devices, with the highest output voltage and current of 150 V and 14 μA, respectively. The high efficiency of the TENG was attributed to the significant nitrogen content within the polyamide structure, where enhanced electrical performance correlated with greater ratios of HMDA. ESO/HMDA biobased polyamides offer an exciting new opportunity for utilization in the fabrication of sustainable energy harvesting devices, such as TENGs.