This study evaluated the effect of milling speed and compaction pressure on the densification and morphology of the CuZn-Gr composite. The composite was prepared by using the powder metallurgy technique. The effect on the microstructural and compaction was determined based on different milling speeds. The different milling speeds involved were 175, 200, 225, and 250 rpm. Meanwhile, the different compaction pressures used in this study were 127, 250, 374, and 500 MPa. The properties of the milled powder gave the result to green density and densification parameters. The XRD pattern of Cu and Zn broadened as milling time increased.

Tannic acid or tannin, type of phenolic compound contains in kenaf bast fibre. Conventional extraction has certain limitations in terms of time, energy, and solvent consumption. Ultrasound assisted extraction (UAE) can extract bioactive components in shorter time, low temperature, with lesser energy and solvent requirement. UAE as alternative extraction technique is better equipped to retain the functionality of the bioactive compounds. In this study, the conditions for ultrasound assisted extraction (UAE) of tannic acid from kenaf bast fibre by assessing the effect of sonication time and different duty cycles were optimized. The use of ultrasound to extract tannic acid from kenaf bast fiber was evaluated. Ultrasound-assisted extraction (UAE) was carried out using ethanol as solvent to intensify the extraction efficacy. Phytochemical screening was conducted to identify the presence of tannic acid in extracts. The extracts then were analyzed using High-Performance Liquid Chromatography (HPLC) and Scanning Electron Microscopy (SEM). It was found that 0.2429 mg/mL of tannic acid was obtained under the extraction conditions of extraction temperature of 40℃, sonication time of 20 minutes and duty cycle of 50%. From SEM analysis, it was found that the raw sample demonstrated rough surface and no porous but kenaf bast fibre display smoother surface with less impurities and few pores appeared after the extraction process using UAE. These results indicate that ultrasound-assisted extraction is an efficient method for extracting tannic acid from kenaf bast fibre with the advantages of lower extraction time and higher extraction yield.