We demonstrate the self-assembly of highly dispersed NiO nanoparticles embedded in lignin-derived mesoporous carbon (MPC) frameworks. Self-assembly is induced by evaporation of the solvent from a mixture of metal-containing liquid crystalline mesophases of lignin-derived polymers and transition metal nitrate hydrate, which yielded NiO@MPC nanostructures at 600 °C under a N₂ atmosphere. The microstructure and morphology of the NiO@MPC are characterized by XRD, TEM and BET. The results show that the NiO nanoparticles are highly dispersed in a mesoporous carbon matrix. The NiO@MPC composites show metal oxide contents in the range 49–79 wt%, high surface areas (503–802 m² g⁻¹), uniform pore sizes (≈3.7 nm), various porous distributions and large pore volumes (0.46–0.68 cm³ g⁻¹). Electrochemical studies were carried out by measurement of cyclic voltammetry (CV) and charge–discharge tests. The results demonstrate that the NiO@MPC composites have high specific capacitance (880.2 F g⁻¹ at a current density of 1.0 A g⁻¹) and display good retention. 90.9% of the specific capacitance is retained when the current density changes from 1 A g⁻¹ to 10 A g⁻¹ in the charge–discharge tests and 93.7% of the specific capacitance is retained after 1000 charge–discharge cycles. Thus, the NiO@MPC composites are promising supercapacitor electrode materials.

A simple approach for the preparation of MOF-derived 2D assembled Ni(OH) ₂ –MnO ₂ /C ternary composites, which are used for flexible supercapacitors, is demonstrated.

The application area of a sound insulation material is highly dependent on the technology adopted for its processing. In this study, thermoplastic rubber (TPR, polypropylene/ethylene propylene diene monomer) composites were simply prepared via an extrusion method. Two microscale particles, CaCO₃ and hollow glass microspheres (HGW) were chosen to not only enhance the sound insulation but also reinforced the mechanical properties. Meanwhile, the processing capability of composites was confirmed. SEM images showed that the CaCO₃ was uniformly dispersed in TPR matrix with ~3 μm scale aggregates, while the HGM was slightly aggregated to ~13 μm scale. The heterogeneous dispersion of micro-scale fillers strongly affected the sound transmission loss (STL) value of composites. The STL values of TPR composites with 40 wt % CaCO₃ and 20 wt % HGM composites were about 12 dB and 7 dB higher than that of pure TPR sample, respectively. The improved sound insulation performances of the composites have been attributed to the enhanced reflection and dissipate sound energy in the heterogeneous composite. Moreover, the mechanical properties were also enhanced. The discontinued sound impedance and reinforced stiffness were considered as crucial for the sound insulation.

Polymer foams are promising for sound absorption applications. In order to process an industrial product, a series of polystyrene (PS) composite foams were prepared by continuous extrusion foaming assisted by supercritical CO₂. Because the cell size and cell density were the key to determine the sound absorption coefficient at normal incidence, the bio-resource lignin was employed for the first time to control the cellular structure on basis of hetero-nucleation effect. The sound absorption range of the PS/lignin composite foams was corresponding to the cellular structure and lignin content. As a result, the maximum sound absorption coefficient at normal incidence was higher than 0.90. For a comparison, multiwall carbon nanotube (MWCNT) and micro graphite (mGr) particles were also used as the nucleation agent during the foaming process, respectively, which were more effective on the hetero-nucleation effect. The mechanical property and thermal stability of various foams were measured as well. Lignin showed a fire retardant effect in PS composite foam.