Triboelectric Performance and Post-Contact Transient Response of Triglyceride–Sulfur Copolymer Paired with Waste-Derived Materials

Triboelectric nanogenerators (TENGs) provide a simple approach for converting mechanical excitation into electrical signals through contact electrification and electrostatic induction. In this work, a triglyceride–sulfur copolymer (TGS), prepared by inverse vulcanization of elemental sulfur with soybean oil, was investigated with two waste-derived counter materials: recycled residual waste plastic (RRWP) and waste goatskin leather (WGL). The TGS–RRWP and TGS–WGL pairs exhibited opposite electrical polarities, with triboelectric charge densities of approximately +41.3 µC m−2 for TGS–RRWP and −56.0 µC m−2 for TGS–WGL, where the sign refers to the charge measured on the TGS electrode. Repeated contact–separation cycling showed an initial conditioning period followed by stabilization of the electrical response. Load-dependent measurements at 1 and 10 Hz revealed maximum output power at approximately 2–4 MΩ, reaching about 2.7 mW for TGS–RRWP and 1.8 mW for TGS–WGL at 10 Hz. Post-contact measurements further revealed reproducible voltage transients after circuit closure while the mechanically conditioned layers remained in static contact. Biexponential fitting showed that the faster decay time increased approximately linearly with effective load resistance, corresponding to apparent effective system capacitances of about 69 pF for TGS–RRWP and 44 pF for TGS–WGL, measured using a high-impedance differential probe to minimize measurement-induced loading, although residual parasitic contributions cannot be excluded. These results demonstrate opposite triboelectric polarity, load-dependent energy conversion, and a reproducible post-contact transient response with a substantial RC contribution.