Key Engineering Materials Vol. 997

Abstract: Nowadays, thermoplastic starch-based biopolymers are an option to be developed into products for domestic use. However, thermoplastic starch (TPS) has poor antioxidant characteristic, which restricts its use in food packaging or films. To address this issue, the starch can be combined with a green and low-cost anti-oxidative agent, to create a new, reasonably priced TPS biocomposites. Anti-oxidative agent that derived from natural sources is the best option due to the non-toxicity, environmentally friendly and abundancy. In this study, the shear mixing and casting processes were employed to form biocomposite films made of TPS, red cabbage, and calcium carbonate with varying calcium carbonate loadings. Prior to the production of the biocomposite, the anthocyanins in the red cabbage was extracted for use as an antioxidant. The biocomposites' structures and morphology were examined using Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). Antioxidant and biodegradability testing were performed to assess the suitability of the TPS biocomposites for biodegradable food packaging application. Results indicate that the antioxidant activity and biodegradability of the TPS improved with the addition of the red cabbage, either in powder form or liquid form. Furthermore, the red cabbage powder not only acts as antioxidant but also as filler together with CaCO₃ to improve the performance of the TPS biocomposite for food packaging application.

Abstract: The non-biodegradable and non-renewable nature of synthetic plastics poses a long-term threat to ecosystems, contributing to environmental pollution and depletion of natural resources. Thermoplastic starch (TPS) is a biodegradable biopolymer and has been identified as one of the best alternatives to replace synthetic polymers, especially in packaging application. In this study, hybrid inorganic/organic fillers were incorporated into the TPS to form hybrid biocomposites films that performed better performance compared to the neat TPS. Oil palm empty fruit bunch (OP) and dolomite (DO) were combined to form the hybrid fillers of the TPS biocomposites in the ratio of 1:4, 2:3, 3:2 and 4:1. Neat TPS was also prepared as control sample. The effect of thermo-oxidative aging on the mechanical properties of all the samples was evaluated. The structure of all samples was assessed using. X-ray Diffraction analysis (XRD) and X-ray Fluorescent (XRF). Based on the results, the TPS films with the hybrid fillers exhibited 61 % increment in tensile strength compared to the neat TPS films. In this study, OP4DO1 is best loading of the hybrid fillers to incorporated in TPS matrix as it achieved the highest value of tensile strength (5.61 MPa), modulus of elasticity (66.13 MPa) and elongation at break (59.93 %). Apparently, this study demonstrates a significant improvement in the tensile properties of the TPS when incorporated with these OP/DO hybrid fillers, thus indicate the potential of utilizing this TPS hybrid biocomposite in packaging applications.

Abstract: There has been a tremendous increase in the amount of emphasis spent on biocomposite technology in recent years. This is primarily due to increased worries about health and the environment. The development of polymer biocomposites is critical in the field of composite material research, particularly in terms of improving mechanical properties and biodegradability. Even though not all polymers are suitable for use as matrix materials, there is growing interest in the usage of renewable polymer matrix architectures such as polylactic acid (PLA) because they degrade more quickly than traditional polymers. In order to produce the biocomposite, the solvent casting method was employed as the appropriate method for production. The material that was used as the filler material was cellulose, and the component of the matrix that was employed was PLA. Chloroform was utilised as the solvent. PLA was employed in the matrix's creation. The sample were cut into rectangles 50 mm long by 15 mm wide. The biocomposite was initially submerged in a buffer solution that contains -amylase in order to kickstart the process of enzymatic biodegradation. In order to finish the procedure without any problems, it was essential to carry out this step. The weight reduction was monitored at two-day intervals. The results showed that as cellulose concentration grew, so did tensile strength, and that weight lost during biodegradation also increased strength was then measured using the ASTM D882 standard. By immersing the sample in α-amylase buffer solution, enzymatic biodegradation was carried out, and the weight loss every two days was determined. According to the outcome, tensile strength rose along with the cellulose content, and the weight lost during biodegradation also increased.

Abstract: Coconut husk materials have become emerging candidates for the industry of furniture and housing due to their properties and abundance in tropical regions. This study explores using coconut chips, a sustainable and biodegradable resource as an alternative material to produce eco-friendly fibrous boards. The binderless chipboards were fabricated from coconut chips using compression molding at different pressing temperatures and times. The binderless chipboards’ thickness, density, and flexural properties were investigated. Results indicate that higher pressing temperatures and longer pressing times result in reduced thickness, lower density, and improved modulus of rupture (MOR) and modulus of elasticity (MOE). Based on the findings of this study, it is suggested that binderless chipboards produced under optimized conditions could offer a viable alternative to traditional wood based particleboards.

Abstract: This research investigates the effect of different particle sizes of recovered carbon black (rCB) on the electrical conductivity, flexural and fractured toughness properties and morphology of epoxy/rCB conductive composites. The rCB powder was a product from the pyrolysis process of waste rubber tires. This research aims for the application of tray production in semiconductor packaging. In this study, the composite was prepared by using a simple mechanical stirring method. The testing and characterizations carried out included electrical conductivity test, flexural test, fracture toughness test, Scanning Electron Microscopy (SEM) and viscosity. The epoxy/rCB conductive composite shows significant differences in electrical conductivity and mechanical properties when incorporated with different particle sizes of rCB. The conductivity percolation threshold was found at 1000 mesh with enhanced mechanical and electrical conductivity properties simultaneously.

Abstract: This paper presents a numerical simulation of a dual-junction tandem GaInp/GaAs cell made from top GaInp and bottom GaAs cells. For this purpose, we utilized a numerical simulation tool. Two methodologies were proposed, the first method consists of simulating each base layer cell of the top and bottom separately, and the second method simulated both layers in one file, to simulate both in one file. For improved electric characteristics of tandem solar cells, the current-match requirement between the top and bottom cells should be satisfied, necessitating the careful design of parameters. The top base GaInp layer thickness is adjusted to match this requirement. The solar spectrum reaching the lower cell is analytically calculated by subtracting the top cell spectrum from the total spectrum. the optimal value of short current density corresponds with a top cell base thickness of 0.8 µm, this results in an open circuit voltage of 2.45 V, a short circuit current of 15.7 Am/cm², a fill factor of 91 %, an efficiency of 35 % for the first method and the second method used a script file designed to verify the above results and confirmed the values to be; 2.68 V open circuit voltage, 15.26 Am/cm², a short circuit current, 90 % fill factor, and 36.86 % efficiency under AM 1.5 G solar spectrum.

Abstract: This research is concerned with the investigation of waste bentonite produced from a quarry in Cyprus, after being polymer-amended for use as a low-density solid additive in water-based drilling fluid systems (WBFS). According to API procedures, the waste bentonite samples are mechanically processed to a size < 63 μm and then activated with soda ash under “wet & thermal” conditions. The activated material is then used in the blending of actual WBF drilling fluid systems amended with polymers to obtain the desired colloidal properties because bentonite alone was not sufficient. For this procedure, three anionic polymers, Xanthan gum, CMC, and PAC-R were considered because they are very common as drilling fluid additives and under certain concentrations can help reach the desired colloidal properties of the WBFS. Results from this work show that minor polymer addition of all three polymers assists the waste material in reaching excellent filtration control qualifying the waste material according to API. Repurposing local waste clay material for drilling applications serves as a cost-effective solution leading to the management of local resources and aligning with environmental sustainability thus contributing to the circular economy principle.

Abstract: The utilization of recycled materials in the production of plastic products is an environmentally conscious and economically viable approach. This study delves into the mechanical and flow properties of low-density polyethylene (LDPE) blends, comparing virgin low-density polyethylene (vLDPE), recycled low-density polyethylene (rLDPE) and vLDPE/rLDPE blends with different ratio (100/0, 75/25, 50/50, 25/75, 0/100) for the purpose of reprocess into variable high-quality end products with minimal modification. Mechanical properties, such as tensile strength, elongation at break, Young’s modulus, flexural strength, and flexural modulus, were examined to assess the suitability of rLDPE in comparison to its virgin counterpart. Our results demonstrate that vLDPE/rLDPE blend exhibits mechanical properties comparable to those of vLDPE, suggesting its potential as a sustainable alternative for reprocessing. Flow properties, specifically melt flow index (MFI), were also assessed to evaluate the processability of the LDPE blends. The findings reveal that the flow properties of LDPE blends are within an acceptable range for extrusion moulding, indicating that these materials can be effectively processed without major adjustments to manufacturing processes. This research underscores the feasibility of incorporating rLDPE into vLDPE for reprocessing into variable products, offering both economic and environmental advantages. By extending the lifecycle of LDPE materials through recycling, we can contribute to reducing waste and the overall environmental footprint while maintaining the desired mechanical and flow properties for high-quality end products.

Abstract: The evaluation and walk-around check before an aircraft flight are essential for ensuring aircraft safety. This paper describes a method for creating a system capable of detecting and identifying damages on aircraft surfaces using imagery captured from UAV-based aerial platforms, achieving real-time Internet of Things (IoT) monitoring via other devices. Our aim in this project is to detect skin damage, such as scratches, cracks, and dents, that pose significant threats to the structural integrity and safety of aircraft. Traditional inspection methods are often time-consuming and labor-intensive, making real-time detection systems essential for timely maintenance and safety assurance.The system utilizes UAVs to capture high-resolution aerial images of aircraft surfaces. These images undergo processing by trained machine learning algorithms to detect and classify desired objects in real time at the ground station. The results of the image processing can then be monitored via IoT devices. Experimental results demonstrate the system's effectiveness and efficiency in identifying skin damage on aircraft materials. However, certain limitations have emerged, including restricted coverage of defect types, reduced accuracy with increased class numbers, and substantial hardware requirements. Despite these shortcomings, the system remains promising for enhancing aircraft safety through proactive maintenance and defect detection.