Biocomposite is a material that have potential to heal injured bones and teeth due to their biocompatible, non-toxic, non-inflammation, and bioactive properties which can prevent infections that occurs frequently during surgical processes. Biocomposites made of PLA, PCL, and HA from bovine bone as a substitute for metal materials in medical applications have been widely studied. However, there are limited studies on the biocomposites made of PLA, PCL, and HA from green mussel shells. Therefore, this study aims to produce biocomposites from Polylactic Acid (PLA), Polycaprolactone (PCL), and Hydroxyapatite (HA) from green mussel shells and to determine the effect of HA concentration on the mechanical properties and degradation rate of the resulting biocomposite. 80 ml of chloroform was used to dissolve 16 grams of a PLA/PCL mixture with a composition of 80% and 20%. After 30 minutes, the solution was agitated for 30 minutes with a magnetic stirrer at 50°C and 300 rpm. After obtaining a homogenous solution, hydroxyapatite was added in percentages of 5%, 10%, 15%, and 20% of the total weight of the PLA/PCL mixture. The resulting mixture is poured into a glass mold in accordance with ASTM D790. Three-point bending, density, and biodegradable test were performed to investigate the effect of HA content on the mechanical properties and degradation rate of the biocomposite. The results of this study indicate that the mechanical properties of the biocomposite improved with the HA concentration increases. However, the more HA content used, the faster the biocomposite degrades.

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The manufacturing of materials, in conjunction with green technology, emphasises the need to employ renewable resources to ensure long-term sustainability. Re-exploring renewable elements that can be employed as reinforcing materials in polymer composites has been a major endeavour. The research goal is to determine how well palm kernel cake filler (PKCF) performs in reinforced epoxy composites. In this study, PKCF with 100 mesh was mixed with epoxy resin (ER) in various ratios ranging from 10% to 40% by weight. Hand lay-up with an open mould is proposed as a method for fabricating the specimen test. Surface modification of PKCF with varying concentrations of NaOH (5 wt.% and 10 wt.%) will be contrasted with the untreated samples. Using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), the effect of alkaline treatment will be examined. The tensile and maximum flexural strength of the untreated PKCF/ER composite were determined in this work, with a 30 wt.% of PKCF having the highest tensile strength of 31.20 MPa and the highest flexural strength of 39.70 MPa. The tensile and flexural strength were reduced to 22.90 MPa and 30.50 MPa, respectively, when the filler loading was raised to 40 wt.%. A 5 wt.% alkali treatment for 1 h improved the composites’ mechanical characteristics. Lastly, an alkali treatment can aid in the resolution of the problem of inadequate matrix and filler interaction. Alkaline treatment is a popular and effective method for reducing the hydroxyl group in fillers and, thus, improving interfacial bonding. Overall, palm kernel cake is a promising material used as a filler in polymer composites.

Recently, the most critical issue related to the use of natural fibre-reinforced polymer composites (NFRPC) is the degradation properties of composites exposed to the environment. NFRPC’s moisture absorption behaviour has adverse effects on the composite’s mechanical properties and dimensional stability. The purpose of this study is to analyse the mechanical properties of epoxy composites reinforced by jute–ramie hybridisation. This study also analysed the effect of stacking sequence hybridisation of the jute–ramie composite on water absorption behaviour. A five-layer different type of stacking sequence of single and hybrid jute–ramie is produced with the hand lay-up method. The results obtained from this study found that the mechanical properties and water absorption behaviour of a single jute fibre are lower compared to a single ramie fibre. The hybrid of jute–ramie has been able to increase the performance of composite compared to pure jute composites. The mechanical properties of the hybrid jute–ramie composite show a reduction effect after exposure to an aqueous environment due to the breakdown of fibre matrix interfacial bonding. However, after 28 days of immersion, all types of the stacking sequence’s mechanical properties are still higher than that of pure epoxy resin. In conclusion, the appropriate sequence of stacking and selecting the material used are two factors that predominantly affect the mechanical properties and water absorption behaviour. The hybrid composites with the desired and preferable properties can be manufactured using a hand-lay-up technique and used in the various industrial applications.

Hydroxyapatite is generally utilized in medical fields especially as a substitute to bone and teeth. Hydroxyapatite nanoparticles have been succesfully synthesized from green mussel shells as a source of calcium carbonate by hydrothermal method. The green mussel shells were calcined, hydrated, and undergone carbonation to form Precipitated Calcium Carbonate (PCC). The PCC of shells was then added with (NH4)2HPO4 with the mole ratio of Ca/P = 1.67. Hydrothermal reaction was carried out at 160oC with variations of the holding time (14, 16, and 18 hrs). The formation of hydroxyapatite was characterized using XRD and SEM-EDX. The XRD patterns showed that the products were hydroxyapatite crystals. The morphology of hydroxyapatite observed using SEM showed that the crystal uniformity of hydroxyapatite. The best result was obtained at 18 hrs holding time of hydrothermal because the hydroxyapatite produced has the highest purity without any impurities phase.

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The braking system is a crucial element in automotive safety. In order for the braking mechanism to function effectively, the brake pads’ durability as well as quality are crucial aspects to take into account. A brake pad is a part of a vehicle that holds the wheel rotation so that braking can occur. Asbestos, which is harmful to human health, is a raw material that is recently being widely used as a material mixture for the manufacturing of brake pads. Many efforts have been made by researchers to find other natural alternative materials to replace the use of asbestos. Natural materials that have received much attention and research include coconut fiber, wood powder or flour, bamboo fiber, shell powder, etc. This review paper focuses on analyzing the main parameters that affect brake pad performance. The composition of filler and fiber types of reinforcement for polymer composites is discussed. Previous studies’ information on the fabrication and testing of brake pads are also highlighted. Furthermore, the findings of this review can provide researchers and academicians with useful information and points to consider for further research.