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.

Sulfur–soybean oil polymers with tunable thermal insulation properties were synthesized via inverse vulcanization of elemental sulfur and soybean oil and reinforced with biochar (BC) derived from spent barley biomass. Biopolymer films (F-BPs) with sulfur contents ranging from 20 to 80 wt% were prepared, and biochar-filled biocomposites (F-BP-Cs) were obtained using different filler loadings and processing routes. Their structural, morphological, thermal, mechanical, and surface properties were systematically analyzed to establish structure–property relationships, with particular focus on thermal transport behavior. Differential scanning calorimetry (DSC) revealed that sulfur contents ≤ 50 wt% favored the chemical incorporation of elemental sulfur into the polymer network via covalent bonding, significantly reducing the presence of free crystalline sulfur in the material. SEM images and porosity analysis revealed that BC incorporation and processing conditions significantly affected microstructural connectivity and air-filled porosity. As a result, F-BP-C materials exhibited low thermal conductivities, reaching values of ~0.033–0.039 W/(m·K), comparable to commercial insulating materials such as cork and polymeric foams. This reduction was attributed to increased structural disorder, high interfacial density, and enhanced phonon scattering within the heterogeneous polymer–BC–air system. These findings demonstrate the potential of these biocomposites as sustainable thermal insulating materials derived from industrial and agricultural waste.

Sulfur–soybean oil polymers with tunable thermal insulation properties were synthesized via inverse vulcanization of elemental sulfur and soybean oil, and reinforced with biochar (BC) derived from spent barley biomass. Biopolymer films (F-BP) with sulfur contents ranging from 20 to 70 wt% were prepared, and biochar-filled biocomposites (F-BP-C) were obtained using different filler loadings and processing routes. Their structural, morphological, thermal, mechanical, and surface properties were systematically analyzed to establish structure–property relationships, with particular focus on thermal transport behavior. Differential scanning calorimetry showed that sulfur contents ≤50 wt% favored effective incorporation into the polymer network, reducing the presence of free crystalline sulfur. Scanning electron microscopy and porosity analysis revealed that BC incorporation and processing conditions significantly affected microstructural connectivity and air-filled porosity. As a result, F-BP-C materials exhibited low thermal conductivities, reaching values of ~0.033–0.039 W·m⁻¹·K⁻¹, comparable to commercial insulating materials such as cork and polymeric foams. This reduction was attributed to increased structural disorder, high interfacial density, and enhanced phonon scattering within the heterogeneous polymer–BC–air system. These findings demonstrate the potential of these biocomposites as sustainable thermal insulating materials derived from industrial and agricultural waste.