Materials Science Forum Vol. 1005

Abstract: Usage of mineral admixture and chemical admixture in concrete or mortar is a usual solution to reach full compaction, particularly where reinforcement blockage and lack of skilled labor happen. In this paper effect of mineral admixtures (Carbon-free fly ash, hereafter CfFA, and normal fly ash) on fresh properties and rheology of mortar have been investigated. As a result, it was confirmed that CfFA increased significantly the fluidity and air content of mortar in comparison to normal fly ash, both in 15% and 30% replacement; however, the flow loss and air stability within one hour were almost equal. In addition, the initial setting time has also been affected by variation of materials. The two mixing of 30% and 15% of CfFA had a shorter setting time in comparison to the mortar with normal fly ash. Furthermore, CfFA based mortar had a great influence on rheology of mortar. Compared to normal fly ash, CfFA Considerably decreased the plastic Viscosity and increased the productivity of the mortar, both in non-vibrated and vibrated condition, particularly those with 30% replacement.

Abstract: In this research, utilizing of Arabica spent coffee ground oil was investigated for textile processing applications including scouring and reactive dyeing for cotton. The spent coffee ground oil was extracted using hexane and its chemical compositions were analyzed. The synthesized biosurfactant from spent coffee ground oil was investigated for use in cotton scouring. The results showed that the biosurfactant could well work as a scouring agent for cotton. Much better water absorption and reduced yellowness on cotton were achieved but higher applied concentration was needed as compared with the commercial wetting agent. It was also found that scouring efficiency of the biosurfactant could be promoted by adding alkali i.e. sodium carbonate, into a scouring bath, resulting in a satisfactory scouring level. A study on utilizing spent coffee ground oil in reactive dyeing process informs that by incorporating the oil into an aqueous dyebath to create oil/water dual-phase dyeing system, the dye exhaustion and color yield of Reactive Red 120 dye obtained on cotton could be enhanced without adding salt. This promotes a development of salt-free reactive dyeing process.

Abstract: Amine-modified solid sorbents have attracted extensive interests in post-combustion carbon capture for power plants. Among various amines, polyethyleneiemine (PEI) is likely to be the most effective and promising candidate. However, previous studies have mainly focused on examining various supports to increase PEI loading and then enhance CO₂ adsorption capacity. In this study, one rare earth element (Ce) and 6 first-row transition metals (from V to Cu) in the oxidation states impregnated on PEI incorporated γ-Al₂O₃ were prepared and investigated as potential catalyst/promotor for base-catalyzed reaction. Thermodynamic analysis, including isothermal and quasi-static CO₂ adsorption tests, were implemented to evaluate the performances amongst the 7 metal oxides. The results showed that MnO₂, CeO₂ and Fe₂O₃ showed a better performance in isothermal CO₂ adsorption at 75°C. Upon quasi-static tests, the results also indicates that the peak adsorption temperatures (T_{peak, a}) of V₂O₅ and Cr₂O₃ shifted to high temperature region, whilst opposite behavior of MnO₂ was observed. In preliminary study, density functional theory (DFT) was also adopted to assist the screening of metal oxide in terms of bond length and adsorption energies.

Abstract: Response surface methodology (RSM) was used to determine the optimal blend of alginate (ALG), poly (vinyl alcohol) (PVA) and graphene oxide (GO), as well as glutaraldehyde (GA) crosslinking solution concentration for the synthesis of dual-crosslinked ALG/PVA/GO nanocomposite hydrogel adsorbent beads for methylene blue (MB) removal. Statistical analyses show that PVA concentration contributes the largest effect to the adsorption capacity response, attributed to improved accessibility of MB molecules to adsorption sites. The optimal blend was determined to be 3% polymer with 50% PVA, 383.8384 ppm GO, crosslinked in 1% CaCl₂ and 5% GA. These results were validated, and the experimental value of the adsorption capacity deviated by only 1.702% from the RSM model prediction, suggesting good model predictability. Adsorption isotherm models were tested to provide a description of the adsorption process. The Sips isotherm model, suggesting monolayer adsorption over heterogeneous surface with action of cooperative adsorbate-adsorbate interactions, was the best fit to the experimental equilibrium data, with an R² of 0.9782. Furthermore, the ALG/PVA/GO beads demonstrated a maximum monolayer adsorption capacity of 1081.62 mg/g, showing superior performance compared to known biosorbents of MB.

Abstract: Polyvinylidene fluoride (PVDF) membranes, enhanced with metal-organic framework (MOF), were fabricated on a non-woven polyethylene terephthalate (PET) support using the non-solvent induced phase inversion (NIPS) method to produce mixed matrix membrane (MMM). Polymer concentration of 10%, 15%, and 20% were used in the study whereas UiO-66(Zr) was used as a MOF filler. The resulting membranes were characterized in terms of their morphology, porosity, wettability, mechanical strength, pure water flux, and gas permeability. Results show that the presence of UiO-66(Zr) filler improved membrane morphology, mechanical strength, and hydrophobicity of MMM as compared to pristine PVDF.

Abstract: Sulphatoethylsulphone reactive-disperse dye was synthesized via diazotization reaction of aminophenyl-4-(β-sulphatoethylsulphone) followed by coupling reaction of the diazonium salt with phenol as a coupling agent. The synthesized dye was well dyeable on both natural and synthetic fibers with providing orange shade on cotton, silk and nylon, while the dyed PLA and PET fibers appeared in yellow shade. The dyeing conditions for cotton and silk could be conducted using 60 g/l Na₂SO₄ and 20 g/l Na₂CO₃ at 60°C for 90 minutes whereas dyeing on PLA and PET fibers was optimally done at 110°C for 30 and 45 minutes for PLA and PET, respectively. In case of nylon, it could be dyed at 100°C for 15 minutes. The synthesized reactive-disperse dye could well dye on these 5 fibers with excellent color fastness to washing.

Abstract: In this study, a combined aroma finishing and pigment printing process was investigated in order to develop 1-step, all-in aroma finishing/pigment printing process for Thai silk. Lemongrass oil microcapsules, an aroma finishing agent, was applied on silk by screen printing process and the properties of the printed fabrics were examined. Pigment printing was also performed individually by screen printing and the colorimetric properties of the print were measured. Binder content affected the print properties of both aroma microcapsules and pigment on silk. An appropriate binder content was chosen at 20 g/100 g print paste. The 1-step, all-in aroma finishing/pigment printing process was performed by printing both lemongrass oil microcapsules and pigment simultaneously on silk fabrics. The process efficiency was determined in two different aspects i.e. aroma finishing effect and coloring effect. Aroma finishing effect of the 1-step, all-in process was examined in comparison with the individual microcapsule print results while the coloring effect was compared between the printed fabric from 1-step, all-in process and the individual pigment printing. The results showed that the 1-step, all-in process could provide comparable aroma finishing effect and pigment print quality to the separated finishing and pigment printing processes.

Abstract: The generation of waste batteries is increasing yearly, and it is more prone to improper disposal resulting in environmental and health concerns. Treatment and handling of this waste are often costly and complex. Hence, an upcycling route to turn such waste into valuable material, specifically the production of graphene from graphite rods of waste batteries, was explored. Graphene dispersions were prepared by the solvent exfoliation of powdered graphite rods. A significant increase in the surface area was observed from 3.75 m² g^-1 (graphite rod powder) to 239.05 m² g^-1 (graphene powder) with a transparent sheet-like appearance. Then, the graphene dispersed in the solvent used for dip-coating of paper, cardboard, and composite plyboard. The tearing strength of paper and cardboard was improved by 70.6% and 31.0%, respectively. The compressive and shear strength of the composite plyboard increased by 14.8% and 72.0%, respectively. These results demonstrate the feasibility of utilizing the graphene solvent from graphite rods of spent primary batteries for the fabrication of composite samples with significantly augmented mechanical properties for various applications.

Abstract: Fused Deposition Modelling (FDM) technology is one of most common technique used in 3D printing as of today for several reasons such as it is low cost and high speed printing capacity. However, common characteristic of FDM 3D printed materials are poor layer adhesion strength and rough surface finish which requires post-processing to improve it. Heat treatment and vapor-polishing are post-processing techniques used to address the poor layer adhesion and rough surface finish of 3D printed materials, respectively. This study will combine these two post-processing techniques and investigate its effect on the mechanical properties of 3D printed materials. The present study describes the effect of acetone vapor-polishing to facture behavior of ABS 3D printed material at higher operating temperatures. The study will compare the fracture behavior of ABS 3D-printed material when polished using acetone vapor bath and tested at high operating temperature to unpolished material. Five replications for each test condition were conducted. All experiment was carried out using ASTM Izod Type E tests with a 2.75J pendulum. The results showed that acetone vapor polishing strongly affects the fracture behavior of ABS 3D printed materials when operating at high temperature.

Abstract: This paper explores the possibility of using different 3d printing methods and materials in the production of polymer molds for injection molding applications. A mold producing a cube was designed using a commercial software. Following the standard 3d printing process, injection molds which could produce a cube were printed using different 3d printing materials and 3d printing technologies. The 3d printing technologies used were Stereolithography (SLA), Polyjet and Fused Filament Fabrication (FFF). A bench-top injection molding machine was used to inject polylactic acid (PLA) in these molds. The quality of the injected parts in terms of dimensional accuracy has been investigated. In some cases, the damage mechanism of the polymer molds has also been observed.