Materials Science Forum Vol. 1142

Abstract: This study investigates the enhancement of hardness and mechanical properties of PPG-based polyurethane elastomers for wheel dolly applications through the incorporationof carbon black and the use of Plast 002 as a dispersing agent. The challenge addressed is the inherent lower mechanical performance of cost-effective PPG-based polyurethane compared to traditional polyester-based alternatives. Three dispersion methods were explored: the impactof Plast 002 on carbon black distribution, varying carbon black content (1, 3 and 5 phr), and comparing high-speed agitation with ultrasonic dispersion. The results indicate that without Plast 002, carbon black tends to agglomerate, leading to significant differences in hardness between the top and bottom of samples, particularly at higher carbon black contents. The addition of Plast 002 significantly improved dispersion, resulting in uniform hardness. Ultrasonic dispersion had more effective than high-speed agitation, delivering higher and consistent hardness values across the sample. Optimal mechanical performance was observed at 1 and 2 phr of carbon black, where tensile strength and modulus improved. The optimized carbon black content and ultrasonic dispersion can significantly enhance the performance of PPG-based polyurethane, offering a more economical alternative to polyester-based polyurethanes for wheel dolly applications.

Abstract: This study synthesized bio-polyols from epoxidized palm oil (EPO) and polysorbate (Tween20), and developed polyurethane foams using these bio-polyols. FT-IR confirmed the formation of urethane linkages, with increased EPO ratios enhancing urethane content. SEM showed that the PU foams exhibited a spherical open-cell structure, with cell sizes increasing at higher EPO ratios. The compressive modulus decreased with higher EPO ratios at an NCO/OH molar ratio of 0.8, whereas compressive strength increased at an NCO/OH molar ratio of 1.0 due to thicker cell walls and enhanced urethane linkages. Resilience tests showed increased energy absorption with higher EPO ratios, attributed to phase mixing and the presence of free urethane and urea. These findings suggest that EPO-based polyol PU foams could be used in applications such as cushioning, noise reduction, and vibration energy mitigation, primarily in the furniture, bedding, carpet underlay, and transportation industries.

Abstract: In this paper, polyethylene terephthalate (PET) fibers were blended with a biodegradable polymer, poly (butylene succinate) (PBS) was investigated in this study. The melt-spinning process produced PET/PBS fibers at the different PBS contents in the PET matrix. We evaluate the effectiveness of the dyeability of PBS contents in PET fibers. The yellow organic dye (Turmeric extract) was used as a coloring agent. The spectrophotometer results show that the dye absorption of the fiber increased with PBS contents. The SEM images confirm the relationship between the dye coating on the fiber and PBS contents in the PET matrix. This indicates that the PBS can act as a compatibilizer or modifier to improve dye penetration and fixation in PET/PBS fibers.

Abstract: In this work, the Fe-Cr-Mo-V-W-C-MoS₂ composites were fabricated using the powder metallurgy process. The uniaxial cold compaction was used to produce green specimens with the density of 6.3 g/cm³. Subsequently, the specimens were sintered at temperatures of 1150 and 1200 °C for 45 min in a vacuum furnace. Sintered specimens were cooled down in the furnace with N₂ at a cooling rate of 0.1 °C/s. The influence of MoS₂ addition on the density, hardness and microstructure were investigated. Density and hardness of composites were improved due to MoS₂ addition, especially, 5 wt.% MoS₂ addition and sintering at 1200 °C. The dissociation of MoS₂ contributed to the formation of sulfide phases and hard carbide particles within the composites. Sulfide phases such as FeS, CrS and other sulfides were detected by x-ray diffraction analysis. The reciprocating wear test was used to study the effect of MoS₂ addition on friction and wear resistance of composites. The synergy of FeS and CrS contained in the compacted layer and hard carbide particle formation within the matrix were expected to enhance tribological properties of composites by decreasing friction coefficient and improving wear resistance.

Abstract: Oil palm empty fruit bunch (OPEFB) is one of the waste by-products when palm oil is produced. Although a waste product, it can be turned into a valuable product by extracting nanocellulose through acid hydrolysis. The process requires a few steps; the most important is the pre-treatment process. In this research, bleaching pretreatment was used to characterize empty oil palm fruit bunches as raw materials for hydrolysis reactions to extract nanocellulose. The bleaching process was done using H₂O₂ and the resulting samples were characterized using FT-IR and SEM. FT-IR analysis revealed that lignin-associated carbonyl groups were removed and there was a decrease in hemicellulose-related acetyl group peaks which confirmed effective pre-treatment. According to Scanning Electron Microscopy (SEM), surface morphology has also changed where the bleached fibres exhibited a rougher surface than the ones that were not bleached. Bleaching is proven to be successful at removing surface impurities, hemicellulose, and lignin and isolating the cellulose for the acid hydrolysis process.

Abstract: Graphene is the only carbon allotrope in which every carbon atom is densely connected to its neighbours by an electronic cloud, raising various quantum physics concerns. In recent years, many researchers have focused their efforts on developing more efficient methods for synthesizing graphene. However, only few methods can simultaneously synthesize mass-produced, cost-effective, and high-quality graphene. In this study, we are emphasizing the use of rice husk (RH) as the raw material to prepare graphene by using two-step pyrolysis. Zinc chloride (ZnCl₂) is an example of an activating agent that is used to improve the efficiency of the synthesis of graphene from rice husk. After conducting pre-treatment of rice husk, the first stage of pyrolysis was conducted by varying the ratio of ZnCl₂ to the RH (1:1, 2:1, 3:1) at a carbonization temperature of 500 °C for 1 hour, followed by second-stage pyrolysis under 900 °C for 90 minutes and post-treatment. The findings of the characterizations, which included yield analysis, scanning electron microscopy (SEM) and Raman spectroscopy, Brunauer-Emmett-Teller (BET), and CO₂ adsorption analysis, revealed the impacts of the ZnCl₂ as activating agent, on the yield and graphitic structure of graphene and the potential application of graphene as a CO₂ adsorbent. Raman spectroscopy confirmed the graphitic properties of graphene synthesized in all samples with RH1:1 produced the best quality of graphene due to its low I_D/I_G intensity ratio (0.8913) and the highest I_2D/I_G intensity at 0.24. In addition, RH1:1 exhibited the highest surface area, whereby the highest total pore and micropore volume is contributing to the highest CO₂ adsorption capacity of 8.73 mmol/g. This proves that the activating agent ratio has significant effects on the graphene quality produced from rice husk as well as the adsorption performance.

Abstract: Biodiesel is a promising alternative energy source instead of fossil fuels that can be produced by the esterification process, which is the reaction of the production of ester compounds by reacting the alcohol with fatty acids in the presence of acid catalysts. In this work, a solid acid catalyst was prepared from cellulose aerogel, which is subsequently pyrolyzed into carbon aerogel before being sulfonated. Cellulose aerogel was derived from coir fiber in the system of NaOH-urea crosslinking solution at −14 °C. Carbon aerogel was produced through pyrolysis at 700 °C for 2 h. The sulfonation process was carried out by adding H₂SO₄ at a temperature of 100 °C for 5 h under atmospheric N₂ conditions. Sulfonated carbon aerogel was characterized by acid density, SAA, SEM, and FTIR analysis. Carbon aerogel obtained by pyrolysis has a larger surface area of 1655.10 m² g⁻¹ than the initial cellulose aerogel of 430.52 m² g⁻¹. A solid acid aerogel catalyst with a surface area of 1322.93 m² g⁻¹ and an acid density of 3.29 mmol g⁻¹ was obtained after the sulfonation process. Esterification reaction involving oleic acid−methanol reactants with molar ratio of 1:9 was carried out at a temperature of 65 °C. Oleic acid conversion of 90.21% was achieved at a catalyst dose of 5% for 2 h.

Abstract: The development of seawater batteries has constraints on oxygen reduction reactions in the battery discharge process that runs slowly. Therefore, an electrocatalyst is needed that accelerates the process. The electrocatalyst developed is a carbon-rich material doped with doping atoms of N and Fe. The effect of adding non-precious metal Fe to nitrogen doped carbon aerogel on the performance of the cathode electrocatalyst in seawater batteries was investigated in this study. This study began with the synthesis of cellulose pulp from palm empty fruit bunch, then progressed to the synthesis of cellulose aerogel by crosslinking NaOH‒Ammonia-Urea with the addition of Fe 5% wt., followed by pyrolysis into carbon aerogel at a temperature of 700 °C. Based on research data, N and Fe doped carbon aerogels have better seawater battery performance than N‒doped carbon aerogels without Fe. Carbon aerogels doped with N and Fe have an iron oxide phase in the form of Fe₃O₄ (magnetite) with a specific surface area of 2869.9 m²/g. Based on the battery test with magnesium alloy anode and 3.5% NaCl electrolyte, cathode with carbon aerogel with N-Fe codoping produces a voltage of 1.4 V, discharge energy of 269.71 mWh and discharge capacity in 1C of 189.76 mWh.

Abstract: Nanotechnology has been the prime approach over the last several decades including in scaling prevention. There has been a flurry of activity in incorporating nanoparticles (NPs) with scale inhibitors (SI) to help mitigate the scales’ growth at the early stage before it worsens. However, despite the increasing use of nanoparticles in industry, reservoir complexity such as salinity and heterogeneity have significantly impacted the nanoparticles' performance in the medium. The nanoparticles' repulsive forces are reduced when brine salinity is present, resulting in flocculation and coagulation of nanoparticles in suspension and phase separation. However, the stability and dispersion of nanoparticles may be improved by altering their characteristics by coating them with a surfactant for a particular application. This can be done by introducing a surfactant in the nanoparticle suspension. Herein, this paper aims to study the dispersion and stability of different types of NPs and their performance in Sodium Dodecyl Sulfate (SDS) surfactant solution. Results obtained proved that carbon-based NPs (graphene oxide (GO) and multi-walled carbon nanotube (MWCNT)) showed an excellent zeta potential measurement up to -116 mV when these NPs were dispersed in SDS solution. This surfactant has significantly improved the NPs stability by increasing electrostatic repulsion between the NPs while reducing the average size of agglomeration.