Self-Healing Thermosets from Camphoric Acid for Fabrication of Biobased Triboelectric Nanogenerators

Bioderived camphoric acid (CPA) was cross-linked with epoxidized soybean oil to yield fully biobased thermosets with self-healing ability at room temperature. The self-healing performance improved with increasing temperature close to the curing temperature of 180 °C, with the welding starting as early as 1 h, and the cut was completely repaired after 16 h. The cross-linker’s rigid 5-carbon ring reinforced the polymeric structure, resulting in a higher Tg (28.9 °C) as compared to aliphatic cross-linkers. The thermoset films exhibited hydrophobic properties, with a contact angle of greater than 90° and excellent thermal stability above 300 °C. These biobased thermosets were synthesized through a facile method in the absence of a catalyst, enhancing the green credential of the products. These thermoset materials were utilized in the fabrication of biobased triboelectric nanogenerators (bio-TENGs). The electrical output performance of the bio-TENG demonstrated significant promise with an output voltage of 75 V and a current of 4 μA. The ESO/CPA thermoset films therefore represent an interesting alternative for manufacturing environmentally friendly TENGs.