Copper nanoparticles have been prepared by electro-reduction process using plating bath containing homogeneously acidified copper sulphate solution. The nanoparticles are formed as spongy layers of ball structures on the plating electrode. The spongy layers of copper can be easily separated to give fine particles. Structural characterizations are done by using X-ray diffraction, X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy. Morphological characterizations are done by scanning electron microscope (SEM) and transmission electron microscope (TEM).

The brittleness of polylactic acid (PLA) has always limited its usage, although it has good mechanical strength. In this study, flexibility of PLA/starch (PSt) blend was enhanced using epoxidized palm oil (EPO) as the green plasticizer. The PLA/starch/EPO (PSE) blends were prepared while using the solution casting method by fixing the content of starch and varying ratio of EPO. The thermal properties, such as glass transition temperature (T_g), melting temperature (T_m), and crystallization temperature (T_cc) were decreased by increasing the amount of EPO into PSt, indicating that EPO increases the chain mobility. Thermogravimetric analysis (TGA) showed that thermal degradation resistance of PSE was higher when compared to PSt. The mechanical testing revealed that EPO at all contents improved the mechanical properties, such as increment of the elongation-at-break and impact strength. Whereas, dynamic mechanical analysis showed that the addition of filler into PLA decreased the storage modulus of PLA. The carbonyl group of the aliphatic ester remained the same in the PSE blends. The morphological study verified the ductility of PSE blends surface when compared to the brittle surface of PSt. As for the soil burial tests, EPO accelerated the degradation of blends. From these results, it can be concluded that EPO improved the flexibility of PLA blends.

Poly (vinyl alcohol) (PVA)-based solid polymer electrolytes doped with ammonium thiocyanate (NH₄SCN) and glycerol were fabricated using a solution casting method. Lithium-based energy storage devices are not environmentally friendly materials, and they are toxic. Thus, proton-conducting materials were used in this work as they are harmless and are smaller than lithium. The interaction between PVA and the electrolyte elements was shown by FTIR analysis. The highest conductivity of 1.82 × 10⁻⁵ S cm⁻¹ was obtained by the highest-conducting plasticized system (PSP_2) at room temperature. The mobility, diffusion coefficient, and number density of anions and cations were found to increase with increasing glycerol. FESEM was used to investigate the influence of glycerol on film morphology. TNM showed that the cations and anions were the main charge carriers. LSV showed that the electrochemical stability window of the PSP_2 system was 1.99 V. The PSP_2 system was applied in the preparation of an electrical double layer capacitor device. The shape of the cyclic voltammetry (CV) curve was nearly rectangular with no Faradaic peaks. From the galvanostatic charge-discharge analysis, the power density, energy density, and specific capacitance values were nearly constant beyond the first cycle at 318.73 W/Kg, 2.06 Wh/Kg, and 18.30 F g⁻¹, respectively, for 450 cycles.

This review provides a comprehensive overview of natural rubber (NR) composites, focusing on their properties, compounding aspects, and renewable practices involving natural fibre reinforcement. The properties of NR are influenced by the compounding process, which incorporates ingredients such as elastomers, vulcanizing agents, accelerators, activators, and fillers like carbon black and silica. While effective in enhancing properties, these fillers lack biodegradability, prompting the exploration of sustainable alternatives. The potential of natural fibres as renewable reinforcements in NR composites is thoroughly covered in this review, highlighting both their advantages, such as improved sustainability, and the challenges they present, such as compatibility with the rubber matrix. Surface treatment methods, including alkali and silane treatments, are also discussed as solutions to improve fibre-matrix adhesion and mitigate these challenges. Additionally, the review highlights the potential of oil palm empty fruit bunch (EFB) fibres as a natural fibre reinforcement. The abundance of EFB fibres and their alignment with sustainable practices make them promising substitutes for conventional fillers, contributing to valuable knowledge and supporting the broader move towards renewable reinforcement to improve sustainability without compromising the key properties of rubber composites.