Mechanical Properties Research Articles

Innovative biopolymers composite based thin film for wound healing applications

Efficient wound and burn healing is crucial for minimising complications, preventing infections, and enhancing overall well-being, necessitating the development of innovative strategies. This study aimed to formulate a novel thin film combining chitosan, carboxymethyl cellulose, tannic acid, and beeswax for improved wound healing applications. Several formulations, incorporating chitosan, carboxymethyl cellulose, tannic acid, and beeswax in various percentages, were utilized to deposit thin films via the solvent evaporation technique, Mechanical properties, morphology, antioxidant activity, antibacterial efficacy, and wound healing potential were evaluated. The optimized thin film (M4), composed of 2% chitosan, 2% carboxymethyl cellulose, and 1% tannic acid, along with 0.2% glycerol and 0.2% tween80, exhibited a thickness of 39.0 ± 1.14 μm and a tensile strength of 0.275 ± 0.003 MPa. It demonstrated a swelling degree of 283.0 ± 2.0% and a drug release capacity of 89.4% within 24 h. The film also showed a low contact angle of 40.5° and a water vapour transmission rate of 1912.25 ± 13.10 g m−2 0.24 h−1. FT-IR spectroscopy indicated that chitosan and carboxymethyl cellulose were cross-linked through amide linkages, with tannic acid occupying the interstitial spaces and hydrogen bonding stabilizing the structure. Microscopy of M4 revealed a uniform morphology. The film exhibited strong antioxidant activity of (95.17 ± 0.02%) and antibacterial efficiency (80.8%) against S. aureus. In a rabbit model, the film significantly enhanced burn and excision wound recovery, with 90.0 ± 3.3% healing for burns and 88.85 ± 1.7% for infected wounds by day 7. Complete skin regeneration was observed within 10–12 days. The M4 thin film demonstrated exceptional mechanical properties and bioactivity, offering protection against pathogens and promoting efficient wound healing. These findings suggest its potential for further investigation in treating various infections and its role in developing novel therapeutic interventions.

Antipolyelectrolyte Response of Amphiphilic Sulfobetaine Polymer Coatings

AbstractZwitterionic, amphiphilic polymer coatings are an effective strategy to decrease biofouling. Yet their performance strongly depends on the mechanical properties, the degree of swelling, and the structure of the swollen hydrogels. These properties depend on the zwitterionic groups in the polymers and the properties of the surrounding electrolyte. Therefore, the influence of the ions present and their concentrations on the swelling behavior of amphiphilic zwitterionic copolymers is studied. Coatings of 3‐[N‐2′‐(methacryloyloxy)ethyl‐N,N‐dimethyl]‐ammoniopropane‐1‐sulfonate (SPE) with increasing amounts of butyl‐methacrylate (BMA) are compared to the respective homopolymers PSPE and PBMA. Surface plasmon resonance spectroscopy shows a salt concentration‐dependent anti‐polyelectrolyte behavior. A variation of the salts revealed that the anions dominated the swelling response, while a change of cations has hardly any effect. Small angle X‐ray scattering reveals the morphological changes in the polymer films that accompanied the swelling. With increasing salt concentration, the internal structure changed from compact pores in a gel‐like network to elongated cylindrical pores at higher salinities. The understanding gained from the presented multi‐technique approach allows to understand the behavior of zwitterionic coatings in saline solutions and helps to tailor the swelling response and mechanical properties for future marine and medical low‐fouling applications.

Influence of Cu and Co addition on metallurgical and wear characteristics of AlCrFeNi high entropy alloy

The creation of new alloys with improved qualities has become essential in modern industries for high-performance materials. This work’s main objective is to use vacuum arc melting (VAM) to synthesize two different high-entropy alloys (HEAs): AlCrFeNiCu and AlCrFeNiCo. The mechanical properties, phase composition, grain boundaries, and alloy composition of the HEAs were studied. The predominant crystal structure, the Body-Centred Cubic (BCC) phase was obtained for both alloys. Significantly, the Co-containing HEA showed a smaller particle size than the Cu-containing HEA, which led to a 14.21% increase in microhardness. It indicates that the Co-based HEA will likely perform better than the Cu-based HEA in applications prone to abrasion, and indentation, and requiring high hardness levels based on the observed microstructure and hardness parameters. According to wear surface morphology studies, main effects analysis and ANOVA show that increasing loads and sliding distances increase wear rate, whereas sliding velocity has less effect. The best wear rate-reducing parameters are 10 N, 0.5 m/s, and 500 m for Cu-containing HEAs, and the same can be predicted using regression analysis. The study categorizes the intricate worn surface structure by describing different surface properties and wear mechanisms, such as grooves, delamination, adhesive wear, and pitting.

Preparation of multiaxial glass fiber/epoxy prepreg and its mechanical properties in composites

Preparation of multiaxial glass fiber/epoxy prepreg and its mechanical properties in composites

Chemical and Solvent‐Based Recycling of DGEBA‐Based Epoxy Thermoset and Carbon‐Fiber Reinforced Epoxy Composite Utilizing Imine‐Containing Secondary Amine Hardener

AbstractEpoxy systems are essential in numerous industrial applications due to their exceptional mechanical properties, thermal stability, and chemical resistance. Yet, recycling epoxy networks and reinforcing materials in epoxy composites remains challenging, raising environmental concerns. The critical challenge is the recovery of well‐defined molecules upon depolymerization. To address these issues, an innovative strategy is developed utilizing imine‐containing secondary amine hardener (M1). The reaction of M1 with DGEBA produced high‐performance epoxy thermoset P1, which exhibits Young's modulus of 2.18 GPa and tensile strength of 63.4 MPa, and excellent stability in neutral aqueous conditions. Upon carbon‐fiber reinforcement, Young's modulus and tensile strength are significantly elevated to 10.99 GPa and 328.3 MPa, respectively. The reactive secondary amine functionalities enabled the tailored network to display a well‐defined growth pattern, yielding only well‐defined molecules and intact carbon fibers upon acidic depolymerization. Consequently, the recycled polymers retained properties identical to those of P1. Notably, it is discovered that despite the cross‐linked nature of the epoxy networks, complete dissolution in dichloromethane facilitated straightforward solvent‐based recycling, allowing the recovery of undamaged carbon fibers and an epoxy thermoset with properties matching the virgin material. Presented novel monomer design and approach showcased two important and efficient recycling options for epoxy systems.

Impact of process parameters on mechanical properties and surface characteristics in hybrid metal additive manufacturing of maraging steel

Impact of process parameters on mechanical properties and surface characteristics in hybrid metal additive manufacturing of maraging steel

Repetitive corrugation and straightening (RCS) of NiTi shape memory alloy strip product

ABSTRACT Repetitive corrugation and straightening (RCS) is a novel method of severe plastic deformation in bulk metallic materials. In this study, the effect of RCS on the properties of NiTi shape memory alloy (SMA) is investigated. Cold-rolled (CR) Ni49.8–Ti50.2 (at. %) strips with varying degrees of cold-work were subjected to RCS and evaluated for transformation, mechanical and functional properties. The study demonstrated that RCS can be used effectively to improve the strength and ductility of the CR SMA strips, while its transformation and functional properties are largely preserved. The ultimate tensile strength (UTS) and elongation to failure of the 30% CR strip post RCS increased from 950 MPa to 1130 MPa and ~19% to ~26%, respectively. The microstructural evaluation confirmed that RCS resulted in notable grain refinement and re-distribution of Ti2Ni second phase in the matrix. Consequent to its high strength, the cyclic response of the RCS strip on stress-free thermal cycling was found to be better than the CR strip.

Enhanced Mechanical and Multifunctional Properties of GNPs/CNTs Hybridized PLA Nanocomposites by Implementing Dual‐Processing of Pickering Emulsion‐Melt Blending Methods

AbstractPolylactic acid (PLA) composites with multifunctional properties and minimal filler content are increasingly in demand across various industries. However, achieving a balance between high mechanical strength, electrical conductivity, thermal conductivity, and electromagnetic interference (EMI) shielding remains challenging. In this study, a dual‐processing strategy combining Pickering emulsion templating and melt blending is presented to hybridize 1D carbon nanotubes (CNTs) and 2D graphene nanoplatelets (GNPs) within a PLA matrix. This approach successfully forms a stable dual‐filler network, ensuring uniform dispersion of the fillers. The results show that this method significantly enhances the performance of the resulting PM‐PGxCy composites (P: Pickering emulsion; M: melt blending; x and y: mass fractions of GNPs and CNTs, respectively). Specifically, the PM‐PG1.43C1.43 composite exhibits remarkable improvements in mechanical strength (56.2 MPa), electrical conductivity (43.5 S m−1), EMI shielding effectiveness (20.1 dB), and thermal conductivity (0.34 W m·K−1), outperforming composites prepared using either method alone. These findings indicate that the dual‐processing strategy effectively combines 1D and 2D fillers, facilitating superior interfacial interactions and enhancing the multifunctional properties of PLA‐based composites. This study offers a new approach to achieving high‐performance PLA composites with low filler content, offering significant potential for applications in electronics, packaging, and EMI shielding technologies.

Cerium Oxide‐Armored Composite Latex Particles by Visible Light Emulsion Photopolymerization: From Synthesis to Film Properties

AbstractCerium dioxide (CeO2) has huge potential in many applications ranging from biochemical engineering to the coating industry. Here, the first example of visible light photo‐mediated Pickering emulsion polymerization of (meth)acrylate monomers is reported using CeO2 nanoparticles (NPs) as solid stabilizer. A ω,ω′−dicarboxylic acid diphenyl disulfide photoinitiator is anchored on the surface of the CeO2 NPs and used to initiate the emulsion polymerization of methyl methacrylate (MMA) and of MMA/n‐butyl acrylate (MMA/BA) under visible light leading to CeO2‐armored latexes. Radicals generated upon light irradiation trigger the formation of polymer chains chemically attached to the CeO2 NPs, promoting their subsequent adsorption on the latex surface. The composite films obtained from the CeO2‐armored P(MMA‐co‐BA) latexes exhibit a unique honeycomb nanostructure with the nanoceria located in the walls giving the materials excellent mechanical, anti‐UV, and photocatalytic properties.

Investigation on the microstructure and mechanical properties of 5356 aluminum alloy wire in continuous casting direct rolling process

Investigation on the microstructure and mechanical properties of 5356 aluminum alloy wire in continuous casting direct rolling process

Microstructure and mechanical properties of new Mg-Zn-Y-Zr alloys with high castability and ignition resistance

Microstructure and mechanical properties of new Mg-Zn-Y-Zr alloys with high castability and ignition resistance

High Entropy Ceramics for Electromagnetic Functional Materials

AbstractMicrowave absorbing materials play an increasingly important role in modern electronic warfare technology for enhancing electromagnetic compatibility and suppressing electromagnetic interference. High‐entropy ceramics (HECs) possess extraordinary physical and chemical properties, and more importantly, the high tunability of multi‐component HECs has brought new opportunities to microwave absorbing materials. Rich crystallographic distortions and multi‐component occupancies enable HECs to have highly efficient microwave absorption properties, excellent mechanical properties, and thermal stability. Therefore, the structural advantages of HECs are integrated from comprehensive perspectives, emphasizing on the role of dielectric and magnetic properties in the absorption phenomenon. Strategies are proposed to improve the microwave absorption capacity of HECs, including composition optimization, microstructure engineering, and post‐treatment technology. Finally, the problems and obstacles associated with high‐entropy materials (HEMs) research are discussed. The innovative design concepts of high‐entropy microwave absorbing ceramics are highlighted.

Bamboo (Dendrocalamus Asper) as an Eco-Friendly Sustainable Material: Optimising Mechanical Properties and Enhancing Load-Bearing Capacity for Environmental Architectural Design

This study will assess the utilisation of Bamboo (a Thai vernacular material) in the construction industry. Bamboo is a sustainable and environmentally friendly material which provides a suitable alternative to traditional construction materials. This research will examine its mechanical strength properties as determined by a review of the existing literature and an examination of the bearing area variations of bamboo nodes. The research data and ensuing experiments facilitated the simulation of the load-bearing capacities of bamboo columnar and beam structures via optimisation. Additionally, this study examined the limitations of bamboo-based structures. The assimilation of mechanical property data and bamboo strength was imperative for the production of load-bearing simulations for bamboo columns and beams within ANSYS software. In many countries, bamboo is a commonly employed construction material because of the many benefits it provides such as its rapid growth speed. The compressive strength tests conducted in this study revealed that the middle nodes could withstand up to 64.9 kN, which was the highest value amongs the three samples tested. These findings will contribute to ongoing optimisation and research regarding the damage mechanisms affecting column and beam structures under load. Notably, this damage was prevalent at the junctures of column and beam interfaces. The intention is to conduct additional research that will enhance the current understanding and ensure the sustainability of bamboo as an architectural building material.

Investigation of nano-basic oxygen furnace slag and nano-banded iron formation on properties of high-performance geopolymer concrete

Abstract Geopolymers have emerged as promising alternatives to traditional cement-based composites, offering enhanced sustainability and opportunities for recycling industrial waste. The incorporation of waste materials into the binding matrix of geopolymer concrete not only promotes environmental benefits but also significantly improves the overall performance, including mechanical strength, durability, and microstructural integrity of the matrix. This study explores the impact of incorporating varying dosages of nano-basic oxygen furnace slag (NBOFS) and nano-banded iron formation (NBIF) on the properties of high-performance geopolymer concrete (HPGC) that utilizes waste glass as 50% fine aggregate. The research focuses on evaluating both the fresh and mechanical properties, including compressive strength, splitting tensile strength, modulus of elasticity, and flexural strength. Additionally, this study investigated the transport properties of concrete under aggressive environments, such as resistance to chloride penetration, sulfate attack, and sorptivity. The microstructure was examined using scanning electron microscopy. The results demonstrated that the addition of 3% NBOFS and 2.5% NBIF significantly improved the fresh, mechanical, and transport properties of HPGC. These nanomaterials also enhance the splitting tensile strength, flexural strength, and elastic modulus under highly aggressive environmental conditions. The contribution of these nanomaterials to the strength and durability of concrete is particularly relevant in the construction of both substructures and superstructures. Additionally, geopolymer concrete significantly reduces CO2 emissions by eliminating the requirement for ordinary Portland cement and promoting the recycling of waste products, contributing to more environmentally friendly construction practices.

Effect of Process Parameters on the Mechanical Properties of Simultaneous Double-Sided Friction Stir Welding Joints

Currently, conventional single-sided friction stir welding is primarily suitable for joining thin plate aluminum alloys, and its application to thick plates is still challenging in terms of welding efficiency and joint mechanical properties. Simultaneous double-sided friction stir welding (SDS-FSW) is a high-efficiency joining technique specifically developed for welding thick plates. However, there is little research on the influence of SDS-FSW process parameters on the joint mechanical properties. In this study, a 12 mm thick AA6061-T6 aluminum alloy and dual robot welding equipment are used to conduct SDS-FSW experiments exploring the influence of rotational speed ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega$$\\end{document} and welding speed v on the mechanical properties and microstructure. The results show that when the welding parameters are ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega$$\\end{document} = 800 r/min and v = 60–80 mm/min, smooth and defect-free thick plate aluminum alloy SDS-FSW joints can be obtained, and the macroscopic morphology of the joints is distributed in a “dumbbell” shape. The grain size in the weld nugget zone increases with increasing welding heat input. The microhardness distribution in the joint displays a “W” shape, and the hardness value of the weld nugget zone can reach 67% to 86% of that of the base metal (BM). The junction between the thermo-mechanically affected zone and the heat affected zone is the weakest region of the joint, with the lowest hardness being approximately 51% of that of the BM. When the welding parameters are ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega$$\\end{document} = 800 r/min and v = 140 mm/min, the SDS-FSW joint has the highest tensile strength, reaching 78.43% of the BM strength and exhibiting ductile fracture characteristics. This research indicates that acceptable weld strength in thick aluminum alloys can be achieved via the SDS-FSW joining mechanism, highlighting its significant potential for industrial applications.

Piezoelectric Actuator-Driven Pulsed Water Jet for Neurosurgery: Laboratory Evaluation with the Swine Model and Implications of Mechanical Properties.

Pulsed water jet is an emerging surgical instrumentation intended to achieve both maximal lesion resection and functional maintenance through preservation of fine vessels and minimal damage to the surrounding tissue. The piezoelectric actuator-driven pulsed water jet (ADPJ) is a new technology that can deliver a precisely controlled uniform and efficient pulsed water jet with minimum water flow. The present study evaluated the ADPJ system in preclinical animal studies in the swine brain, and investigated breaking strength, one of the parameters for mechanical properties, to elucidate the mechanism of tissue selectivity for tissue dissection by the water jet. This system consisted of a pump chamber driven by a piezoelectric actuator, a stainless steel tube, and a nozzle (internal diameter: 0.15 mm). Water was supplied at 6 ml/min. The relationship between input voltage (3-25 V at 400 Hz) and peak pressure was measured using a pressure sensor through a sensing hole. The temporal profile of dissection depth during moving application was evaluated using gelatin brain phantom and swine brain. The dissected specimens were evaluated histologically. The mechanical property (breaking strength) of the swine brain was measured by a compact table-top universal tester. Peak pressure increased linearly with increase in input voltage, which reflected the dissection depth in both the gelatin brain phantom and swine brain. Small arteries were preserved, and minimum damage to surrounding tissues occurred. The breaking strength of the arachnoid membrane (0.12 ± 0.014 MPa) was significantly higher compared with the gray matter (0.030 ± 0.010 MPa) and white matter (0.056 ± 0.009 MPa; p < 0.05). The breaking strength of the gray matter corresponded to that of 3 wt% gelatin, and that of white matter corresponded to a value between 3.5 and 4 wt% gelatin, and the dissection depth seemed to be estimated at 3 to 4 wt% gelatin. The present study suggests that the ADPJ system has the potential to achieve accurate tissue dissection with preservation of blood vessels in neurosurgery. The difference in breaking strength may explain the tissue selectivity between the brain parenchyma and tissue protected by the arachnoid membrane.

Experimental Investigations of the Influence of Spent Coffee Grounds Content on PLA Based Composite for 3D Printing

Nowadays Fused Deposition Modeling, a widely utilized additive manufacturing technology, is significantly transforming as modern production processes. Beyond basic uses to it role in sustainability, Fused Deposition Modeling offers processing potential for implanting circular economy by reducing virgin materials consumption and enhance the integration of waste food for sustainable 3D printing. This research paper investigated the production of new composite materials based on spent coffee grounds. In addition, PLA and SCG at various contents (0, 3, 5, 10, and 15 wt%) were dried and premixed, then processed into PLA/SCG composite pellets using twin-screw extrusion. These pellets were successfully converted into filaments and subsequently used for 3D printing. The effect of spent coffee grounds in PLA composites was investigated via physical and mechanical analysis of 3D printed samples. Regarding density measurements, results revealed that adding up to 5 wt% of spent coffee grounds increased the density while further additions led to a decrease which due to the printing parameters such as extrusion temperature and nozzle diameter. Considering the mechanical properties, the Young’s modulus increased once the spent coffee grounds content reached 3 wt% and then decreased. In the other hand, there was no enhancement in tensile strength and elongation at break which corroborating with density measurements. This mainly contributed to the changes in mechanical properties caused by printing parameters. This study demonstrates that coffee waste can be used as a filler in environmentally friendly composites for 3D printing, with a maximum SCG content of 15 wt%. This approach not only promotes the reuse of coffee waste but also reduces the cost of traditional PLA filaments.

Impact of Graphene Nano particles on static and dynamic mechanical properties of basalt-glass fibre reinforced epoxy polymer hybrid composites

ABSTRACT This paper investigates the structure-property relationships in basalt – glass fabric reinforced hybrid polymer composites doped with graphene nanoplatelets. Basalt Glass fabrics were reinforced with 0.2 wt.% − 0.8 wt.% graphene using hand layup and compression moulding to fabricate laminated plates. The mechanical, morphological, and thermomechanical properties were characterised using tensile, flexural, impact, SEM, FTIR, XRD, and DMA testing. Results showed that low graphene loadings of 0.2 wt.% − 0.4 wt.% led to small, isolated graphene platelets decorating the basalt fibres. At 0.8 wt.% loading, extensive wrinkling, folding, and stacking of graphene sheets on the basalt was observed. FTIR revealed increasing sp2 C=C vibrations and XRD showed rising graphene peak intensities with higher loadings. While tensile and flexural strengths improved up to 0.6 wt.% graphene due to efficient stress transfer, impact energy increased consistently until 0.8 wt.% graphene owing to reinforcement effects. DMA exhibited enhanced storage modulus and restricted mobility with more graphene. An optimum graphene loading of 0.6 wt.% was found to maximise the mechanical performance through uniform dispersion and strong interfacial adhesion. The results demonstrate that graphene incorporation can substantially augment the strength, toughness, and thermomechanical properties of the composites at appropriate compositions prior to aggregation.

Preparation of Phosphorus/Hollow Silica Microsphere Modified Polyacrylonitrile-Based Carbon Fiber Composites and Their Thermal Insulation and Flame Retardant Properties

Since thermal insulation materials with a single function cannot satisfy the increasing requirements for complex usage, the combination of thermal insulation with flame retardancy is desirable in multiple applications. Herein, phosphorous-containing flame retardant modifier (5.0 wt.%, 9.0 wt.%, and 13.0 wt.%) and hollow silica microsphere (130 nm of diameter) were composited with polyacrylonitrile-based carbon nanofibers via electrospinning technique. Electrospun phosphorous/silica/carbon nanofibers (P/HSM/CF) exhibited a uniform and clear fibrous structure (508, 170, and 1550 nm of average fiber diameter) with modified uniform and complete spherical silica. Reduced thermal conductivity (39.9–41.2 mW/m/K) and enhanced limiting oxygen index (29.5–33.5%) were achieved, enabling fire protection grade of fiber membrane from UL-94 V-1 grade to UL-94 V-0 grade efficiently. Moreover, favorable tensile strength (8.64–9.27 MPa) and elongation at break (43.28–48.54%) were obtained, presenting expected applications in structural components. The findings of this work provided a valuable reference for the fabrication of carbon nanofiber-based thermal insulation materials with excellent flame retardant and mechanical properties.

Preparation and performance of waterborne polyurethane coatings based on the intumescent flame retardant of boron, phosphorus, and nitrogen

AbstractPNB organic flame retardant was synthesized using 4‐formylphenylboronic acid, 4‐aminophenylthiophenol, 9,10‐dihydro‐9‐oxa‐10‐phos‐phaphenanthrene‐10‐oxide (DOPO), and then introduced into the hydroxyl‐terminated polybutadiene acrylonitrile (HTBN) molecular chain to successfully prepare a macromolecular flame retardant, which was used to prepare flame retardant waterborne polyurethane. The mechanical properties, thermal properties, and flame retardancy of waterborne polyurethane (FR‐WPU) were studied using thermogravimetic analysis (TGA), limiting oxygen index (LOI), scanning electron microscope (SEM), cone calorimeter, and universal testing machine, respectively, and the flame retardant mechanism of macromolecular flame retardants was explored. An LOI value of 29.76% and a UL‐94 V‐0 rating could be realized when the APFBH conjugation is 7.5 wt%, showing a significant improvement of melt dripping behavior and flame retardancy. It indicated that the fire resistance of FR‐WPU remarkably improved and displayed both gas and condensed phase mechanism. As the content of APBDH increased, the tensile strength and the elongation at break of FR‐WPU increased firstly and then decreased.