Higher Tensile Strength Values Research Articles

Effects of Process Parameters in Thermoforming of Unidirectional Fibre-Reinforced Thermoplastics.

Process-induced defects during thermoforming are widespread problems in laminate manufacturing. The aim of this study is to describe the effects of holding time and pressure on several properties of the manufactured laminate. A design of experiments is performed, followed by an analysis of variance to examine significant effects. Subsequently, a regression model is created to predict the laminate's properties, which is also validated. A significant interaction between holding time and pressure is determined for the resulting tensile strength and elongation at break with a p-value of 1.52·10-16 and 0.02, respectively. The highest values of tensile strength and elongation at break are found for low settings of holding time and pressure. The fibre volume fraction is not affected by the process parameters. As holding time and pressure increase, significant fibre misalignment takes place, leading to a decrease of the mechanical properties. The regression model corresponds well with the validation and a tensile strength of 1049 MPa with an elongation at break of 2.3% is reached.

Optimization of Unsaturated Polyester Resin Matrix Composite Materials Reinforced Banana (Musa Balbisiana) Fronds Composition Towards Tensile Test

This study aims to find out how the physical and mechanical properties of banana tree frond fibers are strengthened by a polyester matrix with various variations of fiber fractions. The study began by making three types of specimens with differences in volume fractions, namely 6% fiber + 94% matrix, 9% fiber + 91% matrix and 12% fiber + 88% matrix with the hand lay – up method. The results of making composites are carried out physical properties testing in the form of density testing, water absorption and thick development and mechanical testing with tensile tests. The results of the physical properties test show that the average density value of each volume fraction variation is above the JIS A509 – 2003 standard. The water absorption value and the thick development of the three fraction variations are still below the maximum limit. While in mechanical properties testing, the highest tensile strength value was obtained at a volume fraction of 12% fiber + 88% matrix with an average tensile strength value of 37.28 MPa.

Synthesis and characterization of new electrospun medical scaffold-based modified cellulose nanofiber and bioactive natural propolis for potential wound dressing applications.

Recently, the design of polymer nanofibers using the electrospinning process has attracted much interest. Particularly the use of natural polymers has promoted many advantages in their biomedical applications. However, the combination of multiple natural polymers remains a great challenge in terms of electrospun production and applied performance. From this perspective, the current investigation highlights the study of the preparation of electrospun nanomaterial scaffolds based on combined natural polymers for improved wound healing performance. First, we have synthesized a crosslinked polymer by reacting microcrystalline cellulose (MC) and chitosan (CS) biopolymer via the intermediate of citric acid as a crosslinking agent. Then a natural propolis biomolecule was incorporated into the polymer network. Different MC/CS blend ratios of 90/10 and 70/30 were then used and various machine parameters were optimized to obtain nanofiber scaffolds with excellent strength and structures. SEM, IR, physicochemical, mechanical, and morpho-logical characterization were then performed. SEM evaluation revealed homogeneous and bead-free nanofibrous structures, with well-defined morphology and a random deposition that could accurately mimic the extracellular matrix of native skin. The calculated average nanofiber diameters for the MC/CS blend ratios at 90/10 and 70/30 were 431.4 and 441.2 nm, respectively. The results showed that when the chitosan amount increased, larger nanofibers with narrow diameter distribution appeared. The prepared nanomaterials had a significant and close water vapor permeability of about 1735.12 and 1698.52 g per m per day for the two blend ratios of 90/10 and 70/30, respectively. The examination of swelling behavior revealed a noteworthy enhancement in hydrophilicity, a necessary attribute for improved healing efficacy. FT-IR analysis confirmed the success and the stability of the chemical crosslinking reaction between the two biopolymers before nanofiber conception. Excellent mechanical properties were acquired, based on the chitosan content. Both developed nanofiber scaffolds exhibited high tensile strength and Young's modulus values. The incorporation of 30% chitosan versus 10% results in an increase in tensile strength of 11% and 14% in Young's modulus. Therefore, we could adjust the different mechanical properties simply by varying the mixing rate of the electrospun polymers. Using epithelial HepG2 cells, viability and kinetic cell adhesion assays were assessed to obtain biological evaluation. No cytotoxicity was observed and good cytocompatibility was confirmed. Functionalized nanofiber biomaterials with different MC/CS ratios substantiated significant bactericidal effectiveness against Gram-positive and Gram-negative bacterial culture strains. The novel functional electrospun wound dressing scaffold demonstrated effective and promising biomedical performance, healing both acute and chronic wounds.

Review of MIG and TIG welding current variation of low-carbon steel materials based on tensile strength

SS400 and ASTM A36 a low-carbon steel materials that are used in the industry in the connection process to create materials according to the design. The aim of this research is to review the mechanical properties that occur in low-carbon steel materials in the MIG and TIG welding process with current variations and provide advice on low-carbon steel in welding. The materials used are ASTM A 36 and SS 304 steel. MIG welding uses a plate with a thickness of 6mm and uses AWS A5.18 ER 705-6 electrode diameter of 1.2mm. TIG welding uses a cylinder with a diameter of 6mm. The method of this review reported the tensile strength of low-carbon steel ASTM A36 with current variations of 150, 155, and 160A for MIG. Current variations of SS304 low-carbon steel are 80, 100, and 120A for TIG. The result of tensile strength with the MIG process produces the highest average current of 150 A of 354.92MPa. The results of tensile strength TIG process for 100A of 1007.31 MPa. The suggestion of this review is in MIG welding a greater current is required to obtain a high tensile strength value than the current required for TIG welding on low-carbon steel ASTM A 36 with a carbon content of 0.29% C and on SS304 with a carbon content of 0.042% - 0.07% C. Welding for stainless steel material can be used on TIG welding to get maximum tensile strength values. For ASTM A36 steel materials, MIG welding can be an option.

Thermal and Mechanical Properties of Polymeric Films Based on PLA / PBAT and Corn Starch and Babassu Mesocarp Starch by Flat Extrusion for Packaging

The influence of different amounts (1, 3 and 5%) of commercial corn starch and of babassu mesocarp starch on a (polylactic acid)/poly (butylene co-terephthalate adipate) (PLA/PBAT) based blend obtained by flat extrusion was ascertained. The thermal and mechanical properties were determined and the results obtained are independent of the type of starch employed but are dependent on its concentration, the nucleating effect of the different starches and on the mobility of the polymer chains that make up the blend. Thermogravimetric analysis indicated the presence of two defined stages of mass loss for all films under investigation. Tensile testing shows that films containing starch had similar behavior to that of PLA in the PLA/PBAT blend, presenting high values of tensile strength, elastic modulus and tensile strength and low values of strain at break. The results suggest that babassu mesocarp starch is viable alternatives to the production of packaging films.

Investigation on the Attainment of High-Density 316L Stainless Steel with Selective Laser Sintering.

Due to the low density of the green part produced by selective laser sintering (SLS), previous reports mainly improve the sample's density through the infiltration of low-melting metals or using isostatic pressing technology. In this study, the feasibility of preparing high-density 316L stainless steel using 316L and epoxy resin E-12 as raw materials for SLS combined with debinding and sintering was investigated. The results indicated that in an argon atmosphere, high carbon and oxygen contents, along with the uneven distribution of oxygen, led to the formation of impurity phases such as metal oxides, including Cr2O3 and FeO, preventing the effective densification of the sintered samples. Hydrogen-sintered samples can achieve a high relative density exceeding 98% without losing their original design shape. This can be attributed to hydrogen's strong reducibility (effectively reducing the carbon and oxygen contents in the samples, improving their distribution uniformity, and eliminating impurity phases) and hydrogen's higher thermal conductivity (about 10 times that of argon, reducing temperature gradients in the sintered samples and promoting better sintering). The microstructure of the hydrogen-sintered samples consisted of equiaxed austenite and ferrite phases. The samples exhibited the highest values of tensile strength, yield strength, and elongation at 1440 °C, reaching 513.5 MPa, 187.4 MPa, and 76.1%, respectively.

Optimization of an edible film formulation by incorporating carrageenan and red wine lees into fish gelatin film matrix

The study aimed to use response surface methodology (RSM) to create and understand a novel edible film made from fish gelatin (FG). This film includes wine lees (WL) and carrageenan (CAR). The concentrations of WL (0, 1, 2, and 3 %) and CAR (0, 1, and 3 %) were considered independent variables. The process variable combinations for the optimal response functions were 1.926 % WL and 3 % CAR, forming soft and rigid films with low tensile strength (TS) and high elongation at break (EAB%). Based on the evaluation of each response, FG film had the highest TS value, FG/CAR(3 %) film had the maximum EAB, and FG/WL (3 %)/CAR (3 %) film had the lowest vapor permeability (WVP) and the highest opacity (OP). The incorporation of WL considerably improved the functional properties of these films, enabling strong antioxidant activity and high phenolic content. Characterization of the films with analytical techniques: Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis demonstrated a considerable interaction between WL and FG, indicating a high level of compatibility between the two substances. Our data suggest that the formulation of edible films can be adjusted to fit the specific requirements of the design.

The effect of carbon nanoparticles on cellulosic handsheets

Abstract This article describes the study of the effects of carbon nanoparticles on fibrous cellulosic webs. The handsheets were coated with coating colours containing graphene oxide (GO), carbon nanotube (CNT) and super conductive black carbon (SCBC) nanoparticles at different concentrations. The Raman method was used to assess the quality of the carbon materials and the changes in the band gap of the nanoparticles deposited on the handsheets. The influence of the type and content of the nanoparticles on the structural, mechanical, chemical and electrical properties of the composites was investigated and discussed. It was found that the range of failure modes and fracture surfaces seen in the SEM image is due to the influence of the different carbon materials as the main source of coating colour. The experimental percolation threshold curve and the total surface electrical resistivity of the samples were investigated. The SCBC coated samples exhibited low percolation threshold and comparatively high electrical conductivity at a certain maximum concentration. Each composite exhibited a pronounced stress distribution along the surface layer and the nanoparticle distribution was uniform. The surface resistance of the coated handsheets declined by about 14.103 times with the addition of only 1.0 wt% SCBC compared to the control sample. The composites coated with GO and SCBC nanoparticles at a concentration of 1.0 wt% had the highest tensile strength values.

Parametric based optimization of friction stir welded wrought AZ80A Mg alloy employing response surface methodology

An endeavour was put forward to friction stir weld flat plates of AZ80A Mg alloy by employing the central composite based design technique of response surface methodology, taking into consideration the parameters namely tool rotational speed, traverse speed, tool’s tilt angle, and pin geometry of the employed tool. Numerical model was formulated to correlate the relationship amidst the employed parameters of FSW process and the responses, namely tensile strength and elongation percentage of the AZ80A Mg alloy joints. The formulated model was also optimized to attain AZ80A Mg alloy joints possessing highest value of tensile strength. Competency of the formulated numerical model was validated employing the analysis of variance and the observations of the affirmation experiments plotted in the form of scatter diagrams revealed an appreciable agreement with the values of the anticipated models. Response and contour plots generated from the established numerical model was employed to understand the interactive impacts of the parameters of FSW process on the variables of the response. AZ80A mg alloy joints fabricated during the employment of tool possessing straight cylindrical geometry at atilt angle of 0.630, rotational speed of 962.077 rpm, tool traverse speed of 2.105 mm sec−1 possessed the highest tensile strength of 195.299 MPa and was proven to be free from flaws.

Making of Biodegradable Plastic Based on Corn Starch (Amylum Maydis) with Addition of Acid (CH3 COOh) and Gliserol Plasticizer

Almost all countries face the problem of plastic waste due to the large production of conventional plastics and the long degradation process. Therefore, to protect nature from the accumulation of plastic waste, research on biodegradable plastics needs to be done. Biodegradable plastics are made from starch, cellulose, chitosan, and proteins extracted from renewable biomass. Starch for making biodegradable plastics can be obtained from plants, one of which is corn. This study aims to determine the effect of the composition of acetic acid, glycerol and corn starch on the quality of biodegradable plastics which include tensile strength, elongation and biodegradation. The independent variables were variations of acetic acid and glycerol. Control variables are plastic mold size, corn starch mass of 5 grams, other compounds outside the independent variables. The dependent variable is tensile strength, elongation and biodegradation. To test the tensile strength and elongation of biodegradable plastic, Ultimate Testing Machine Mini was used. The results showed that the addition of acetic acid and glycerol to the corn starch and glycerol blending material had an effect on increasing the tensile strength value and reducing the elongation and biodegradation values of biodegradable plastics. The highest tensile strength value is 50.04 Mpa, obtained from the addition of 1.44% acetic acid and 35.71% glycerol from a volume of distilled water of 70 ml. The highest length gain or elongation of 90% was obtained from the addition of 0.48% acetic acid and glycerol as much as 21.43% of the 70 ml volume of distilled water. Percent weight loss of the largest plastic obtained from the addition of acetic acid as much as 0.48% and glycerol as much as 21.43% of the volume of distilled water as much as 70 ml, which amounted to 93.33%.

Fabrication of Gentamicin Sulfate‐Loaded 3D‐Printed Polyvinyl Alcohol/Sodium Alginate/Gelatin‐Methacryloyl Hybrid Scaffolds for Skin Tissue Replacement

Abstract3D‐printed scaffolds can better mimic the function of human skin, both biologically and mechanically. Within the scope of this study, the effect of the addition of different amounts (10, 15, 20 mg) of gentamicin sulfate (GS) to a 10 mL solution of natural and synthetic polymers is investigated. Sodium alginate (SA), gelatin‐methacryloyl (GelMA), and polyvinyl alcohol (PVA) are chosen as bioactive materials. The surface morphology and pore structures are visualized by scanning electron microscopy (SEM). According to the results, it is observed that the pore sizes of all scaffolds are smaller than 270 µm, the lowest value (130 µm) is obtained in the scaffold loaded with 15 mg GS, and it also has the highest tensile strength value (12.5 ± 7.6 MPa). Similarly, it is observed that the tensile strength (9.7 ± 4.5 MPa) is high in scaffold loaded with 20 mg GS. The biocompatibility test is performed with fibroblast cells, and the results show that the scaffolds are biocompatible with cells. The antibacterial test is carried out against the S.aureous and E. coli and the results indicate that all GS‐loaded scaffolds demonstrate antibacterial activity.

Preparation of Multifunctional Additive [MFA] from Castor Oil (CO) and Study of its Effects on the Physical Properties of Natural Rubber Vulcanizates

This experiment focuses on the synthesis of Multifunctional Additives (MFA) from Castor seed oil (CO) and pure Oleic acid (OA) respectively. These multifunctional additives (CO-MFA and OA-MFA) were investigated as potential substitutes for process oil, activator, co-activator, and accelerator in the formulation of a natural rubber vulcanizate. During processing, the castor seed oil was characterized for acid value (AV), free fatty acid (FFA) and saponification value (SV) and subsequently reacted with 1, 6-hexane diamine to obtain a mixture of salts termed castor oil-based multifunctional additives (CO-MFA), similarly, a pure oleic acid was also reacted with 1, 6-hexane diamine to obtain a pure salt termed oleic acid-based multifunctional additive (OA-MFA). These compounds were investigated as substitutes for process oil/stearic acid, process oil/stearic acid/zinc oxide, process oil/MBT, and process oil/stearic acid/zinc oxide/MBT in the formulation and compounding of natural rubber vulcanizate. The pre-mastication of the rubber and subsequent mixing with additives was carried out in a Banbury Internal Mixer at a rotor speed of 50 rpm for 7 mins while the vulcanization was achieved on a compression molding machine at a temperature of 140oC for 15 mins. The various vulcanizates samples were evaluated for tensile properties, compression set, abrasion resistance, and hardness. The use of castor seed oil-based multifunctional additives (CO-MFA) as a substitute for process oil/stearic acid/zinc oxide/MBT gave the highest value of tensile strength (12.24 MPa) as against the conventional rubber compound (4.21 MPa).

Анализ механических свойств и характеристик свободных колебаний полимерного композита на основе переплетенных обработанных волокон джута

Introduction: Recently, the use of natural fibers have been increased to replace the use of synthetic fibers to save our environment from waste disposal problems, natural fibers have a lower level of mechanical properties. The purpose of work: This study examines the effect of treating the surface and deeper layers of jute fiber on the mechanical behavior and characteristics of free vibrations of a composite material based on it. The methods of investigation: due to the uniform distribution of stresses in the WARP and WEFT directions, four-layer basket weave jute fibers were used in this study. Result and discussion: the mechanical and free vibration properties of composite materials are significantly improved when NaOH is applied to jute fibers because it eliminates the weak matrix material lignin and makes the fibers stiffer and stronger. However, increasing the percentage of NaOH and soaking time for the fibers in NaOH solution have little effect on these properties. The highest value of tensile strength and tensile modulus are found 50 ± 1.17 MPa and 1.94 ± 0.23 GPa respectively seen in case of basket weave jute fiber composite with 1 hour treatment. Tensile strength and tensile modulus increase about 12 % and 40 % over the stokes value, respectively. Similarly the value of flexural strength and flexural modulus are found 95 ± 1.17 MPa and 3.99 ± 0.23 GPa respectively in case of basket weave jute fiber composite with 1 hour treatment. It also shows the highest value of fundamental frequency 77.837 Hz.The presence of an O-H bond in the composite, as revealed by FTIR study, gives it a hydrophilic character and limits its use in humid environments. The fiber to matrix ratio is shown in SEM images.

Sulfur and Cystine Content in Various Sheep Wool Breeds and Their Correlation with Wool Growth and Strength

This scholarly article presents a comprehensive analysis of sulfur and cystine content in the wool of various sheep breeds, with a particular focus on their relationship with wool growth and strength. The breeds under scrutiny include the Askanian fine-wool, Prekos, Latvian dark-headed, Ukrainian Carpathian mountain, and Karakul breeds. Our research revolves around wool samples extracted from the scapula area before the spring shearing process. Our findings reveal that the highest sulfur content is observed in the wool of Karakul sheep (3.05 %) and Prekos sheep (2.90 %), whereas the lowest sulfur content is noted in Latvian dark-headed sheep (2.65 %). Conversely, the highest cystine content is exhibited in the wool of Askanian fine-wool sheep (11.87 %) and Prekos sheep (11.46 %), while the lowest cystine content characterizes the wool of Karakul sheep (8.99 %) and the Latvian dark-headed breed (10.10 %). The genetic factors, specifically breed-specific characteristics, impact on the rate of wool growth. The most rapid growth rates are observed in Karakul sheep (873 mg/cm/day) and Askanian fine-wool sheep (857 mg/cm/day). Slightly lower growth rates are noted in Prekos breed sheep (844 mg/cm/day) and Ukrainian Carpathian mountain breed sheep (766 mg/cm/day). The lowest growth rates are recorded in Latvian dark-headed sheep (742 mg/cm/day). Furthermore, we establish that the highest tensile strength values are associated with the coarse wool of Karakul sheep (9.6 cN/tex) and the semi-coarse wool of Ukrainian Carpathian mountain sheep (9.3 cN/tex), as these fibers possess the thickest cuticular layer. Conversely, the lowest tensile strength values are observed in the wool of Latvian dark-headed sheep (7.0 cN/tex) and Prekos breed (7.1 cN/tex). An examination of the data reveals that there is no statistically significant correlation between the content of sulfur and cystine and the rate of wool growth. However, a robust direct correlational relationship is identified between the sulfur content and fiber strength (with correlation coefficients of r = 0.831 for Karakul breed sheep wool, 0.713 for Latvian dark-headed, 0.698 for Ukrainian Carpathian mountain, 0.544 for Askanian fine-wool, and 0.460 for Prekos breed wool).

MECHANICAL BEHAVIOR OF AN HIGH STRENGHT STEEL (AHSS) WITH MEDIUM MN CONTENT IN TWO ROLLING CONDITIONS: HOT AND WARM

The microstructure before intercritical annealing of an AHSS (Advanced High Strength Steel) with medium Mn content plays an important role in the final mechanical properties, since the transformations occurring during annealing modify phases, composition, and morphology. The microstructural changes that occur during intercritical annealing treatment of a medium Mn steel were examined. Two starting material comes from different conditions, hot rolling at 1200°C and warm rolling (initial rolling at 1200°C and subsequent at 680°C). The mechanical properties were related to the transformation phenomena that occur in these steels, mainly TRIP (Transformation Induced Plasticity) and TWIP (Twinning Induced Plasticity) effects. The transformations were verified by SEM (Scanning Electron Microscopy) and X-RD (X-Ray Diffraction). Tensile strength values of 1111 MPa and 17% elongation were obtained by hot rolling route. For the warm rolling route, 35% deformation and a tensile strength of 1357 MPa were obtained. The strain hardening curve was analyzed, showing the presence of the TWIP effect subsequently "saw" behavior related to the discontinuous TRIP effect. The mechanic properties values are related to the difference in morphology phases present. An acicular morphology of a/? (ferrite/austenite) provides a higher value of tensile strength, but low elongation percentage, and a mixture of lamellar and globular morphologies, provides an optimized combination of strength and ductility. Key words: AHSS, medium manganese steel, rolling, heat treatment, discontinuous TRIP effect, TWIP.

Tension and bending behaviors of 3D printed PLA+ at different printing parameters

3D-printed polylactic acid (PLA+) is one of the newest biodegradable materials seeking entrance into the industrial field. The effect of 3D printing process parameters (infill pattern (IP), infill density (ID), layer height (LH), line width (LW), shell thickness (ST), printing temperature (PT), printing speed (PS), and raster angle) on mechanical properties has been studied. In addition, this paper aims to investigate the effect of changing both the IP and raster angle on the mechanical properties of 3D-printed PLA+. The results revealed that the highest value of tensile strength can be obtained at an ID of 100%, concentric IP, LH of 0.1[Formula: see text]mm, LW of 0.8[Formula: see text]mm, ST of 0.8[Formula: see text]mm, PT of 215∘C, and PS of 60[Formula: see text]mm/s.

The highly stable indicator film incorporating roselle anthocyanin co-pigmented with oxalic acid: Preparation, characterization and freshness monitoring application

A novel stable PVA/HPMC/roselle anthocyanin (RAE) indicator film co-pigmented with oxalic acid (OA) was prepared, its properties, application effects and stability enhancement mechanism were investigated correspondingly. The structural characterization revealed that more stable network was formed due to the co-pigmentation facilitated generation of molecular interactions. Meanwhile, the co-pigmentation improved film mechanical and hydrophobic properties compared to both PVA/HPMC/RAE newly prepared (PHRN) or stored (PHRS) film, expressing as higher tensile strength values (12.25% and 14.44% higher than PHRN and PHRS), lower water solubility (7.22% and 10.09% lower than PHRN and PHRS) and water vapor permeability values (33.20% and 21.05% lower than PHRN and PHRS) of PVA/HPMC/RAE/OA newly prepared (PHON) or stored (PHOS) film. Compared with the PHRS film, the PHOS film still presented more distinguishable color variations when being applied to monitor shrimp freshness, owing to the stabilization behaviors of co-pigmentation in anthocyanin conformation. Hence, the co-pigmentation was an effective strategy to enhance film stability, physical and pH-responsive properties after long term storage, leading to better film monitoring effects when applied in real-time freshness monitoring.

Circular Production, Designing, and Mechanical Testing of Polypropylene-Based Reinforced Composite Materials: Statistical Analysis for Potential Automotive and Nuclear Applications.

The circularity of polymer waste is an emerging field of research in Europe. In the present research, the thermal, surface, mechanical, and tribological properties of polypropylene (PP)-based composite produced by injection molding were studied. The pure PP matrix was reinforced with 10, 30, and 40% wt. of pure cotton, synthetic polyester, and polyethylene terephthalate post-consumer fibers using a combination of direct extrusion and injection molding techniques. Results indicate that PP-PCPESF-10% wt. exhibits the highest value of tensile strength (29 MPa). However, the values of tensile and flexural strain were lowered with an increase in fiber content due to the presence of micro-defects. Similarly, the values of modulus of elasticity, flexural modulus, flexural strength, and impact energy were enhanced due to an increase in the amount of fiber. The PP-PCCF-40% wt. shows the highest values of flexural constant (2780 MPa) and strength (57 MPa). Additionally, the increase in fiber loadings is directly proportional to the creation of micro-defects, surface roughness, abrasive wear, coefficient of friction, and erosive wear. The lowest average absolute arithmetic surface roughness value (Ra) of PP and PP-PCCF, 10% wt., were 0.19 µm and 0.28 µm. The lowest abrasive wear value of 3.09 × 10-6 mm3/Nm was found for pure PP. The erosive wear value (35 mm3/kg) of PP-PCCF 40% wt. composite material was 2 to 17 times higher than all other composite materials. Finally, the single-step analysis of variance predicts reasonable results in terms of the p-values of each composite material for commercial applications.

Enhancing CO2 separation from N2 mixtures using hydrophobic porous supports immobilized with tributyl-tetradecyl-phosphonium chloride [P44414][Cl

The main obstacles in adopting solvent-based CO2 capture technology from power plant flue gases at the industrial scale are the energy requirements for solvent regeneration and their toxicity. These challenges can be overcome using new green and more stable ionic liquids (ILs) as solvents for post-combustion CO2 capture. In the current study, tributyl-tetradecyl-phosphonium chloride [P44414][Cl] as an IL, was immobilized on hydrophobic porous supports of polypropylene (PP), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE) at 298 ± 3 K and pressures up to 2 bar. The surface morphology indicated homogenous immobilization of the IL on the membrane support. Supported ionic liquid membranes (SILMs) were tested for CO2 permeability and CO2/N2 selectivity. None of the SILMs exhibited IL leaching up to 2 bar. The PTFE-based SILM performed better than other supports with minimum loss in water contact angle (WCA) and achieved good antiwetting with a maximum CO2 permeability and selectivity over N2 of 2300 ± 139 Barrer and 31.60 ± 2.4, respectively. This work achieves CO2 permeability about two-fold more than other works having CO2/N2 selectivity range of 25–35 in similar SILMs. The diffusivity of CO2 and N2 in [P44414][Cl] was measured as 3.64 ± 0.18 and 2.01 ± 0.09 [10−8 cm2 s−1] and CO2 and N2 solubility values were 9.79 ± 0.47 and 0.19 ± 0.001 [10−2 cm3(STP) cm−3 cmHg−1], respectively. The high values of Young's modulus and tensile strength of the PTFE support-based SILM (234 ± 12 MPa and 6.07 ± 0.31 MPa, respectively) indicated the long-term application of SILM in flue gas separation. The results indicated phosphonium chloride-based ILs could be better solvent candidates for CO2 removal from large volumes of flue gases than amine-based ILs.

Comparative assessment of gas and water atomized powders for additive manufacturing of 316 L stainless steel: Microstructure, mechanical properties, and corrosion resistance

In this study, the microstructure, and mechanical properties of 316 L stainless steel (SS316L) produced by laser powder bed fusion (LPBF) using water-atomized (WA) and gas-atomized (GA) powders were compared. The results showed that the use of WA powder, with a finer average particle size and better spreadability, led to significantly higher values of tensile strength (UTS), yield strength (YS), elongation (El%), and toughness in the WA samples (728 MPa, 580 MPa, 31.8%, and 215 J/m3, respectively) compared to the GA sample (602 MPa, 503 MPa, 25.2%, 145 J/m3, respectively). The WA samples also exhibited a non-uniform hardness distribution and superior work-hardening rate due to the presence of multiple inclusions that tightly bound to the matrix and created stress fields, increasing the required energy for dislocation motion. The higher solidification rate of melt pools in the WA sample left more intensive residual stress with distorted grains, exhibiting a higher grain orientation spread (GOS). Additionally, a multitude of geometrically necessary dislocations (GNDs) formed around the boundaries of elongated grains with tilted boundaries to maintain lattice continuity, resulting in a higher kernel average misorientation (KAM) and congestion of low-angle grain boundaries (LAGBs), particularly in the WA sample. XRD patterns confirmed the higher lattice distortion in the WA sample, and the smaller cellular structures observed in SEM images were consistent with the higher dislocation density observed in the WA specimens. Finally, the WA sample exhibited lower surface roughness and rather higher resistance to corrosive media containing chlorides.