Key Engineering Materials Vol. 985

Abstract: Current research is carried out for newly developed of Bio-CPNC biomaterial nanocomposite for dentistry applications. The developed Bio-CPNC is invented of clay-based polymer CPNC and palm-tree micro-fibers, where CPNC is composed by nanotechnology of HDPE and MMT nanoclay. The research contains the methodology of design, processing, testing and characterization mainly focusing on mechanical and fracture properties, microstructure morphology and testing of thermal effect changes due to surrounding temperature changes. The necessity for finding new biomaterials and new techniques for dental materials for restoration and orthodontics with high biocompatibility with human bones and tissue are the aim for developing this natural bio-nanocomposites to be instead of using ceramics and metals like titanium. The new developed bio-CPNC dental material have special mechanical, thermal and fracture properties to resist the effects of occlusal loads of mastication with sustainability without expecting bad effects with orofacial esthetics and normal lingual ability because it is green. It can be applied for different types of orthodontics like crowns, bridges and dental implants. The study included processing, design, testing and characterization of different properties. The testing included detailed fundamental experimental work for investigation of the changes of mechanical and fracture properties based on fracture mechanics science. The results and comparison are promising where they are showing large enhancement of the mechanical, fracture and thermal properties of Bio-CPNC in comparison to the polymer material which encourage the researchers, dentists, and dental-companies for extra research to stabilize these natural green Bio-CPNC nanocomposite for dental applications with reducing the cost where all materials components are available locally in comparison to use of conventional ceramics materials or expensive zirconia composites.

Abstract: In our research, we demonstrate an innovative process for preserving polyphenolic compounds in a selected plant extract through a modified encapsulation technique. This can enhance preservation strategies and unlock potential industrial applications. The polyphenolic contents of butterfly pea (Clitoria ternatea) were extracted using the reflux extraction method using distilled water as a solvent. The flower-to-solvent ratio was 1:20 w/v. The total phenolic contents of C. ternatea extract were evaluated. To keep the stability of the phenolic contents in C. ternatea extract, the encapsulates of extract were performed using different combinations of wall material. In preparation for encapsulation, sodium alginate was used as the main wall material, which cooperated with other wall materials including gum arabic, maltodextrin, and casein sodium salt. The encapsulation which was performed using 3.0% w/v of sodium alginate mixed with 1.0% w/v of gum arabic, and C. ternatea extract in 5.0% w/v of CaCl₂ solution provided a smooth surface and spherical shape of the particles. However, the optimized condition of encapsulation of C. ternatea extract using the combinations of wall materials which reveal thermal stability and degradation of polyphenolics was performed using 3.0% w/v of sodium alginate mixed with 1.0% w/v of casein sodium salt, and C. ternatea extract in 5.0% w/v of CaCl₂ solution. This condition exhibited the highest thermal stability at 205°C and offered the lowest polyphenol contents degradation at 2.76±0.52 gallic acid equivalents/100 mg dried bead. The average particle sizes of encapsulates using the three conditions of 3.0% w/v of sodium alginate mixed with 1.0% w/v of casein sodium salt, gum arabic, and maltodextrin were 1247, 977, and 1210 µm in diameter, respectively. This method would be an alternative way to prevent polyphenolic compound degradation and boost shelf life at high temperatures in many potential applications.

Abstract: Single crystal of [Ni(4-AP)₄(NCS)₂] complex compound has been obtained using solvothermal method at 70 °C for 15 hours (yield = 41%). Crystal structure of [Ni(4-AP)₄(NCS)₂] has a distorted octahedral structure with orthorhombic crystal system, Pccn space group, Z = 4, and a, b, and c values of 17.1091(5) Å, 9.6686 (3) Å, 16.1998 (5) Å. Hirshfeld Surface analysis shows that intermolecular hydrogen bonds in the complex compound comes from N–H∙∙∙∙N and N–H∙∙∙∙S. The intermolecular interactions are dominated by H---H, C---H/H---C, and H---S/S---H by 39.0%, 29.6%, and 24.7%, respectively. The relatively less contributions are N---H/H---N, S---C/C---S, and S---N/N---S at 6.3%, 0.2%, and 0.1%, respectively. The [Ni(4-AP)₄(NCS)₂] complex has antibacterial activity against Escherichia coli and Staphylococcus aureus.

Abstract: This research aims to synthesize and characterize Ni(II)-terephthalate-pyrazine complex and to determine the thermal stability and porosity profile of the synthesized compound. The Ni(II)-terephthalate-pyrazine was made by solvothermal reaction using dimethylformamide at 130 and 150 °C and in Ni(II):terephthalic-acid:pyrazine mol ratios of 1:1:2 and 1:1:4. The precipitated products were characterized by infrared spectroscopy, SEM, and powder-XRD in order to confirm the presence of both ligand in the synthesized compound. Meanwhile, the thermal stability and porosity profile of the synthesized compound were determined by DTA-TGA and surface area analysers, respectively. Experimental data shows that green pale powder was obtained from all reactions in considerably good yield, which is different from the dark green crystalline solid of Ni(II)-terephthalate. SEM image reveals that the product has a smooth-wavy surface morphology. Infrared spectra of the synthesized compound show peaks of functional groups of C=O, C–O, C=N, and C–N groups, which confirm the presence of both ligands. Powder XRD analysis suggests that the crystal system of the synthesized compound is different from that of the Ni(II)-terephthalate. Based on these analyses, the targeted Ni(II)-terephthalate-pyrazine is successfully obtained. Moreover, the synthesized compound has lower thermal stability than that of Ni(II)-terephthalate, while the BET calculation suggest that the synthesized compound has pore volume of 0.10-0.14 cm³/g, pore diameter of 8.1-10.65 nm and surface area of 24-30 (m²/g). This porosity profile suggest that the synthesized compound is open for further application, such as adsorption or photocatalysis.

Abstract: Hematite (α-Fe₂O₃) has been synthesized from iron sand using the coprecipitation method. This study aims to determine the morphology and mineral content using SEM-EDX, crystal structure and phases formed using XRD, and magnetic properties using VSM on iron sand before and after synthesis. SEM-EDX results show that the average particle size of iron sand before and after synthesizing is 356.23nm and 12.40 µm, respectively. XRD results show that iron sand before synthesizing has multipahase including Hematite, magnetic, and ilmenite and after synthesizing produces Single Phase hematite. VSM results show that iron sand before synthesizing has saturation, remanence, and coercivity of 47.56 emu/g, 5.97emu/g, and 121.03 Oe respectively, and after synthesizing has saturation, remanence, and coercivity of 9.47 emu/g, 1.53 emu/g and 102.97 Oe respectively.

Abstract: Inclusion compound based on crystalline water is increasingly recognized as a promising solution for carbon dioxide (CO₂) capture, either for carbon sequestration from greenhouse gas emissions or for gas mixture separation. Molecular dynamics simulations revealed that water crystallizes into a novel porous structure in a carbon nanobrush environment even at room temperature, thus termed ”hot” ice whose structure code is dtc. This study employs a hybrid Grand Canonical/isothermal-isobaric Monte Carlo (GCMC) simulations to investigate CO₂ confinement inside the cylindrical channels of ice dtc structure. The results show that CO₂ occupancy, here expressed as CO₂-to-water mole ratio, is approximately 2:5 at maximum. The simulations also demonstrate the mechanical stability of ice dtc structure under positive pressures when its voids are filled with CO₂. Furthermore, molecular dynamics simulations are performed to provide molecular insights into the structures and dynamics of CO₂ inside the porous channels framework. The results show that CO₂ molecules form a bilayer structure inside the cylindrical channels, where certain molecule orientation angles are favored. Dynamics analysis shows that CO₂ molecules are relatively immobile in all directions at maximum occupancy.