Dody Ariawan

Adding flame‐retardant fillers to Glass Fiber Reinforced Polymer (GFRP) composites used for cabin car panels can improve flammability resistance and enhance passenger safety. Research on GFRP composites with nano Active Filler of Pumice Particle (nAFPP) and Sodium Silicate (SS) fillers has been conducted to evaluate the composites with FTIR, thermal properties (TGA‐DSC), flammability performance (ASTM D 635), and emission (smoke particle matter). The GFRP composite with 5 wt.% nAFPP and 5 wt.% SS exhibits the highest burning residue at 27.5% among the others, whereas the filler‐free composite shows the lowest burning residue at 20.99%. The DTG test indicates that composites with fillers decompose longer than those without. All composites with fillers exhibit amorphous nAFPP, indicated by sharp exothermic curves of crystallization. The DSC test shows higher heat flow during crystallization and melting, indicating exothermic and endothermic processes, respectively. Adding SS filler offers greater flammability resistance advantages than nAFPP. The filler‐free composite has the lowest flammability resistance with a burning rate of 0.494 mm/s, whereas the specimen with 7 wt.% nAFPP and 3 wt.% SS achieved the best flammability resistance with a burning rate of 0.215 mm/s. The SS proves more effective in enhancing flammability resistance. The use of fillers reduces smoke‐particle pollutants in GFRP composites, and SS is a better inhibitor of particle matter in smoke. Industries have an opportunity to improve GFRP composite products, and further investigation is needed to achieve the excellence of GFRP composites.

Polymer foams are increasingly used in sandwich composites to achieve a high stiffness-to-weight ratio. This study scientifically investigates polymer foam cores for sandwich composites from 1966 to 2024. Using 2220 articles (426 sources) from Scopus, Bibliometrix (Biblioshiny), and VOSviewer, the publication dynamics were measured, networks between sources, authors, and countries were mapped, and the co-occurrence of keywords was determined. This area is growing rapidly (9.51% per year; 29.82 citations/article) and can be divided into three phases: Beginning (1966–1996), Developing (1997–2011), and Booming (2012–2024), with a shift in topics from basic mechanics to interfacial engineering, impact behavior, and multifunctionality. Composite Structures have emerged as the main source, with China and the United States dominating, while international collaboration remains low (20.14%). The material landscape and manufacturing routes demonstrated the applications of polymer foam in insulation, structural components, and energy absorption. The keyword analysis revealed that bio-based and sustainable applications strengthen niche markets. The proposed roadmap for the future recommends prioritizing leading journals, partnering with high-performing groups, and focusing on recyclable thermoplastics and sustainability-oriented studies, accompanied by transparent numerical validation and life cycle analysis.

Aluminum matrix composites (AMCs) reinforced with industrial by-products have attracted attention as lightweight, sustainable materials, yet most research has focused on fly ash. The higher density of bottom ash compared to fly ash makes bottom ash suitable for use as reinforcement in AMC. This study investigates the combined effect of BA reinforcement (0, 3, and 6 wt%) and T6 heat treatment (aging at 175, 200, and 225 °C) on the microstructure, mechanical performance, thermal expansion, and dimensional stability of AA6061 composites. Mechanical testing, thermomechanical analysis (TMA), and coordinate measuring machine (CMM) evaluations were conducted to establish correlations between microstructure and macroscopic reliability. The results show that aging plays a decisive role in strengthening and stabilizing the alloy. The unreinforced AA6061 achieved peak hardness (69.43 BHN) and tensile strength (274.60 MPa) at 200 °C, but exhibited the largest distortion due to high thermal expansion. BA addition significantly reduced the mean coefficient of thermal expansion, with the 3 wt% BA composite aged at 200 °C demonstrating the most balanced behavior: stable CTE response, minimal distortion (0.1–0.4 mm²), and improved mechanical reliability. In contrast, 6 wt% BA composites, despite their lowest mean CTE (≈25 ppm/K), suffered from local instabilities due to particle agglomeration and porosity, leading to reduced toughness and higher geometric irregularities. Overall, this work highlights the novelty of employing BA as a sustainable reinforcement distinct from fly ash, showing that moderate BA addition coupled with optimized heat treatment can enhance dimensional stability and mechanical performance. The findings provide new insights into the design of cost-effective, environmentally friendly AMCs for structural applications.

The properties of polylactic acid (PLA) are encouraging as a bioplastic that could substitute conventional petroleum-based plastics. The objective of this research is to enhance the mechanical properties of PLA for a broader range of applications by incorporating Microcrystalline Cellulose (MCC) as a filler. Solvent blending is employed in conjunction with sonication to incorporate MCC into the PLA matrix. The MCC composition varies in 0 and 10wt%, and the sonication time was varied by 0, 5, 10, and 15 min. The results of mechanical testing on composite PLA sheets, which included the tensile test (ASTM D638) and puncture test (ASTM 2582), indicated that the presence of MCC can enhance tensile strength and puncture resistance. The efficacy of the sonication was demonstrated for five minutes. This is due to the effective dispersion of MCC in PLA, which leads to an increase in the tensile strength and puncture resistance of PLA. The morphological image shows that the MCC dispersion after 5 minutes of sonication is more homogeneous than at other durations. Experimental results indicate that the homogeneous dispersion of fillers in bioplastics contributes to the enhancement of tensile strength and puncture resistance.

The increasing amount of tire waste has become a global environmental problem due to its non-biodegradable nature and potential to pollute the air, soil, and water. One solution is to recycle the tire waste into Styrene Butadiene Rubber (SBR) as a filler in polymer composites for 3D printing filaments. This study aims to analyze the effect of adding SBR on the physical, mechanical, and thermal properties of Polypropylene (PP) composites. The methods used included extrusion and filament molding with variations in SBR mass fraction: 0%, 5%, 10%, and 15%. Density testing, tensile testing, thermal analysis, and morphological observation were conducted. The results show that theoretically, the density of the composite increases with the addition of SBR, but in practice, the density decreases due to the formation of voids. The increase in porosity also affects the mechanical properties. The tensile tests show an 8.8% increase in the tensile strength with a 5% addition of SBR, but a significant decrease with 10% and 15% additions due to the particle agglomeration and poor interfacial adhesion. The thermal stability decreases slightly with the addition of SBR, as seen from the earlier degradation and increased post-Thermogravimetry Analysis (TGA) residue. The surface morphology becomes rougher with an increase in the SBR fraction, affecting the quality of the 3D prints. It can be concluded that the addition of up to 5% SBR improves the mechanical properties, whereas further increases in the fraction result in a decline in the material performance. This study demonstrates the potential for utilizing tire waste in the production of PP/SBR composites for 3D printing applications with the necessary formulation and process optimization.

This study investigates the effects of different synthesis parameters of Acrylonitrile Butadiene Styrene/Microcrystalline Cellulose (ABS)/(MCC) composites on their physical, mechanical, and morphological properties. Composites were fabricated using a twin-screw extruder followed by hot pressing, with variations in the MCC volume fraction (0–8 vol%), screw speeds (10–20 rpm), and extrusion temperatures (150–170 ℃). Density and flexural strength tests were conducted in accordance with ASTM standards, and the surface morphology was analyzed using Scanning Electron Microscopy (SEM). The results showed that incorporating 2–4 vol% of MCC improved both density and flexural strength by reducing voids and enhancing interfacial bonding. However, higher MCC contents led to particle agglomeration and diminished performance. A lower screw speed of 10 rpm facilitated better filler dispersion and stronger interfacial adhesion, yielding the highest flexural strength. Conversely, excessive screw speeds and elevated extrusion temperatures caused filler degradation, matrix shrinkage, and void formation, negatively impacting composite integrity. These findings demonstrate that careful optimization of filler content and processing parameters is essential to produce high-performance ABS/MCC composites with improved structural and mechanical characteristics.

The stir casting process involves several key parameters, including agitation speed, agitation time, holding time, stirrer size and dimension, stirring position, and particle treatment. This study evaluates the effect of stirring depth and surface particle modification on the hardness and tribological properties of Al6061-Al2O3 composites. These composites were manufactured using the current method at a temperature of 720 oC, with an agitation speed of 600 rpm for 10 minutes. The reinforcement consisted of 6%wt Al2O3 particle, while 2.5%wt Mg was added as a wetting agent. The results indicate that the optimum stirrer depth was 30% of the molten metal height, leading to enhanced hardness (66.5 HBN ) and reduced specific wear rate (1.17x10-4 mm3/Nm). Additionally, the electroless coating treatment at a stirrer depth of 30% improved wettability, further increasing hardness, and lowered the specific wear rate (70.2 HBN and 1.10x10-4 mm3/Nm). These findings highlight the importance of stirrer depth optimization and surface modification techniques in enhancing the mechanical and tribological performance of Al6061-Al2O3 composites.

Exposure to humid environments can influence the behaviour of the composite brake pad. The use of hazardous materials in brake pads poses health risks. Therefore, it is essential to utilise more environmentally friendly materials. The brake pads in this study, composed of 35 vol. % phenolic resin, 25 vol. % eggshell particles, 10 vol. % bamboo fibre, 5 vol. % bamboo particles, 10 vol. % alumina powder, 5 vol. % zinc powder and 10 vol. % graphite powder, underwent a rigorous manufacturing process involving cold compaction, hot compaction and post-curing. The samples were immersed in engine oil for 12, 24, 36 and 48 hours. The results of the study indicated that composites made from calcined eggshell and bamboo particles maintained their performance even after being exposed to engine oil. Following this exposure, the composites exhibited a coefficient of friction ranging from 0.33 to 0.36, a friction stability coefficient between 71.59 and 79.19, a flexural strength ranging from 7.23 to 8.25 MPa and a flexural strain ranging from 0.54 to 1.11 %. Additionally, the wear rate experienced a slight increase, measuring between 4.75 and 6.64 mm3/m. The flexural modulus was found to be between 4.44 and 5.49 GPa, while the hardness ranged from 43.35 to 91.05 HRR.