Strong Mechanical Performance Research Articles

Finite element analysis and clinical study of chest wall reconstruction using carbon fiber artificial rib

Carbon fiber composites are emerging as a promising new biomaterial for chest wall reconstruction implants due to their mechanical properties and biocompatibility. This work evaluates the biomechanics of carbon fiber artificial ribs using finite element analysis and clinical implementation. Static simulations of normal breathing process show the maximum stress on the implant is only 2.83 MPa, far below the material ultimate strength of 60 MPa, indicating the excellent fit for maintaining respiratory function. Dynamic collision simulations demonstrate the artificial rib model could withstand a 4 kg rigid object impact at 2 m/s without fracture. Reconstructing the artificial rib with a human rib in the finite element analysis model increases the overall stress tolerance. The impact force required for fracture increases 48% compared to the artificial rib alone, suggesting improved strength from rib integration. Clinically, 10 of 13 patients receiving the artificial rib implants show no significant loss of pulmonary function based on spirometry tests. Based on our findings, the combined simulations and clinical results validate the strong mechanical performance and biocompatibility of the carbon fiber artificial ribs for chest wall reconstruction under static and dynamic loading while maintaining normal respiratory function.

A design of 2-DoFs spherical parallel manipulator with adjustable workspace

Spherical parallel manipulators (SPMs) have promising industrial applications due to their strong mechanical performance. However, they face challenges such as singularity avoidance, tight tolerance manufacturing requirements, and the need for versatile and dexterous end-effector functionalities. Additionally, SPMs lack customizability due to singularity and collision issues. This work introduces a novel design principle that addresses these challenges by benchmarking two analytical methods: structural synthesis using screw theory and dimensional synthesis using dimensionless parameters. A proof of concept of a 2-DoF SPM that can operate within a cylindrical constraint and realize a full workspace without collision is presented. This design allows for adjustable reachable workspace at the end-effector, despite significant geometric constraints. These findings on mechanical design solutions provide customizability for SPMs, and a 3D model with an aspect ratio of 1/12 is presented and discussed for potential practical applications. Overall, it is identified that both a simulation using Recurdyn and inverse kinematic model show the desired movements at the moving platform with the maximum error of 0.0013°.

Robust and Scalable In Vitro Surface Mineralization of Inert Polymers with a Rationally Designed Molecular Bridge.

The artificial integration of inorganic materials onto polymers to create the analogues of natural biocomposites is an attractive field in materials science. However, due to significant diversity in the interfacial properties of two kinds of materials, advanced synthesis methods are quite complicated and the resultant materials are always vulnerable to external environments, which limits their application scenarios and makes them unsuitable for scalable production. Herein, we report a simple and universal approach to achieve robust and scalable surface mineralization of polymers using a rationally designed triple functional molecular bridge of fluorosilane, 3-[(perfluorohexyl sulfonyl) amino] propyltriethoxy silane (PFSS). In a two-step solution deposition, the fluoroalkyl and siloxane of the PFSS take charge of its adhesion and immobilization onto polymers by hydrophobic interaction and wrapping-like chemical cross-linking, and then the assembly and growth of inorganic nanoclusters for integration are achieved by strong chemical coordination of PFSS sulfonamide. The versatile mineralization of inorganic oxides (e.g., TiO2, SiO2, and Fe2O3) onto chemically inert polymer surfaces was realized very well. The resultant mineralized materials exhibit robust and multiple functionalities for hostile applications, such as hydrophilic membranes for removing oils in strong acidic and alkaline wastewaters, fabrics with advanced anti-bacteria for healthy wearing, and plates with strong mechanical performance for better use. Experimental results and theoretical calculations confirmed the homogenous distribution of the PFSS onto polymers via cross-linking for robust coordination with inorganic oxides. These results demonstrate a skillful enlightenment in the design of high-performance mineralized polymer materials used as membranes, fabrics, and medical devices.

An information encrypted heterogeneous hydrogel with programmable mechanical properties enabled by 3D patterning.

Heterogeneous architectures with defined patterns found in nature have stimulated the burgeoning development of biomimetic materials. However, the construction of soft matter like hydrogels that mimic biological materials with a combination of strong mechanical performance and unique functionality remains difficult. In this work, we developed a simple and adaptable strategy of a 3D printing complex structure within hydrogels utilising all-cellulosic materials (hydroxypropyl cellulose/cellulose nanofibril, HPC/CNF) as ink. The structural integrity of the patterned hydrogel hybrid is ascertained by the interfacial interaction between cellulosic ink and the surrounding hydrogels. Through designing the geometry of the 3D printed pattern, programmable mechanical properties of hydrogels are achieved. In addition, the thermally induced phase separation properties of HPC confer thermally responsive behaviour on patterned hydrogels, providing them potential to be assembled into double information encryption devices and shape-morphing materials. We anticipate that this all-cellulose ink-enabled 3D patterning technique within hydrogels can serve as a promising and sustainable alternative for designing biomimetic hydrogels with desired mechanical properties and functions for a variety of applications.

Avient introduces new long fiber reinforced PKE

On December 12, 2022, Avient Corporation announced an expansion to its range of polyketone (PK) based materials with new Complēt™ PKE long fiber reinforced engineered thermoplastics. The new formulations should broaden options for customers looking for strong mechanical performance to support demanding applications, even in cold environments.

Construction of an antibacterial hydrogel based on diammonium glycyrrhizinate and gallic acid for bacterial- infected wound healing

The current antibacterial wound dressings with antibiotic substances or metal bactericidal agents may lead to severe multidrug resistance and poor biocompatibilities. Herein, we report an inherent antibacterial hydrogel constructed by only two naturally small molecules gallic acid (GA) and diammonium glycyrrhizinate (DG) for promoting Staphylococcus aureus (S. aureus)-infected wound healing. The resultant GAD hydrogel can be fabricated by co-assembly of these two materials through simple steps. Thanks to the incorporation of GA and DG, GAD hydrogel enabled a strong mechanical performance and great self-healing property with a sustained-release of drugs into skin wounds. Moreover, the cell viability assays showed that GAD hydrogel had good cytocompatibility by promoting cell proliferation and migration. In addition, GAD hydrogel had broad antibacterial efficiency against both Gram-positive and Gram-negative bacteria. Taken together, GAD hydrogel is a promising dressing to accelerate bacterial-infected wound healing through reconstructing an intact and thick epidermis without antibiotics or cytokines.

Nanocomposite conductive tough hydrogel based on metal coordination reinforced covalent Pluronic F-127 micelle network for human motion sensing

The design of conductive hydrogels integrating anti-fatigue, high sensitivity, strong mechanical property and good sterilization performance remains a challenge. We innovatively introduced metal coordination in covalently crosslinked Pluronic F-127 micelle network and synthesized nanocomposite conductive tough hydrogel through the combination of covalent crosslinking, metal coordination and silver nanowire reinforcement. Compared with pure diacylated PF127 hydrogel (PF127), the tensile strength of PF-AA-AM-Al3+/Ag0.25 hydrogel reaching 1.4 MPa was about 10 times than that of PF127. The toughness of PF-AA-AM-Al3+/Ag0.25 reaches 1.88 MJ/m3. Compared with PF-AA-AM-Al3+, the introduction of silver nanowires increased the fatigue life of PF-AA-AM-Al3+/Ag0.25 by 200% (31837 cycles), 170% (12804 cycles) and 1022% (511 cycles) under 100%, 120% and 150% ultimate tensile strains, respectively. Besides, the PF-AA-AM-Al3+/Ag0.25 showed strain sensitivity to small deformation (Gauge factor = 2.42) in wearable tests on hands and knees. In addition, the PF-AA-AM-Al3+/Ag0.25 had good cytocompatibility and antibacterial performance that bacteria killing ratio of 98% to S. aureus and 99% to E. coli. Finally, a viscoelastic numerical constitutive model was established based on finite element method to study the damage failure history of the material. Comparative analysis showed that local stress concentration was the main factor leading to the failure of hydrogel.

Hydrogen-Bonding Affords Sustainable Plastics with Ultrahigh Robustness and Water-Assisted Arbitrarily Shape Engineering.

Herein, the supramolecular plastic-like hydrogel (SPH) is introduced as a platform to fabricate sustainable plastics with ultrahigh stiffness and strength as well as water-assisted arbitrarily shapeable capability. The transparent plastics are constructed from SPHs of cellulose ether/polycarboxylic acid complexes and demonstrate mechanical robustness with Young's modulus up to 3.4GPa and tensile strength up to 124.0MPa, superior or comparable to most common plastics. Meanwhile, the shape of the plastics can be reversibly engineered by air drying of the SPHs with diverse 2D/3D shapes and structures, which are generated conveniently via origami, kirigami, embossing, etc., in virtue of plastic deformation and shape memory effect of SPHs. On the basis of multi-dimensional infrared-spectral analysis, it is revealed that the dense acid-acid and acid-ether hydrogen (H)-bonding network in the plastic is responsible for the mechanical robustness while the evolution of water-polymer H-bonds into polymer-polymer H-bonds during air drying contributes to the shape fixing. This work provides a novel method of manufacturing sustainable plastics with simultaneous strong mechanical performance and convenient processibility from hydrogels with plastic-like mechanical behavior.

Gelatin-Reinforced Zwitterionic Organohydrogel with Tough, Self-Adhesive, Long-Term Moisturizing and Antifreezing Properties for Wearable Electronics.

Strong mechanical performance, appropriate adhesion capacity, and excellent biocompatibility of conductive hydrogel-based sensors are of great significance for their application. However, conventional conductive hydrogels usually exhibit insufficient mechanical strength and adhesion. In addition, they will lose flexibility and conductivity under subzero temperature and a dry environment owing to inevitable freezing and evaporation of water. In this study, a tough, flexible, self-adhesive, long-term moisturizing, and antifreezing organohydrogel was prepared, which was composed of gelatin, zwitterionic poly [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) (PSBMA), MXene nanosheets, and glycerol. Natural gelatin was incorporated to enhance mechanical performance via the entanglement of a physical cross-linked network and a PSBMA network, which was also used as a stabilizer to disperse MXene into the organohydrogel. Zwitterionic PSBMA endowed the organohydrogel with good adhesion and self-healing properties. Long-term moisturizing properties and antifreeze tolerance could be achieved owing to the synergistic water retention capacity of PSBMA and glycerol. The resulting PSBMA-gelatin-MXene-glycerol (PGMG) organohydrogel exhibited high mechanical fracture strength (0.65 MPa) and stretchability (over 1000%), excellent toughness (3.87 MJ/m3), strong and repeated adhesion to diverse substrates (e.g., paper, glass, silicon rubber, iron, and pig skin), good fatigue resistance (under the cyclic stretching-releasing process), and rapid recovery capacity. Moreover, the PGMG organohydrogel showed good stability under -40 °C. The sensor based on PGMG organohydrogel could tightly attach to the human skin and real-time-monitor the motions of joints (e.g., bending of the finger, wrist, elbow, and knee) and the change in mood such as smiling and frowning. Therefore, PGMG organohydrogels have a huge potential for wearable sensors under room temperature or extreme environments.

Biosynthetic Structural Proteins with Super Plasticity, Extraordinary Mechanical Performance, Biodegradability, Biocompatibility and Information Storage Ability

AbstractDegradable bioplastics have attracted growing interest worldwide. However, it is challenging to develop bioplastics with a simple processing procedure, strong mechanical performance, good biocompatibility, and adjustable physicochemical properties. Herein, we introduced structural proteins as building blocks and developed a simple environmentally friendly approach to fabricate diverse protein‐based plastics. A cost‐effective and high‐level production approach was developed through batch fermentation of Escherichia coli to produce the biomaterials. These bioplastics possess super plasticity, biocompatibility, biodegradability, and high resistance to organic solvents. Their structural and mechanical properties can be precisely controlled. Besides, high density information storage and hemostatic applications were realized in the bioplastic system. The customizable bioplastics have great potential for applications in numerous fields and are capable to scale up to the industrial level.

Biosynthetic Structural Proteins with Super Plasticity, Extraordinary Mechanical Performance, Biodegradability, Biocompatibility and Information Storage Ability.

Degradable bioplastics have attracted growing interest worldwide. However, it is challenging to develop bioplastics with a simple processing procedure, strong mechanical performance, good biocompatibility, and adjustable physicochemical properties. Herein, we introduced structural proteins as building blocks and developed a simple environmentally friendly approach to fabricate diverse protein-based plastics. A cost-effective and high-level production approach was developed through batch fermentation of Escherichia coli to produce the biomaterials. These bioplastics possess super plasticity, biocompatibility, biodegradability, and high resistance to organic solvents. Their structural and mechanical properties can be precisely controlled. Besides, high density information storage and hemostatic applications were realized in the bioplastic system. The customizable bioplastics have great potential for applications in numerous fields and are capable to scale up to the industrial level.

Flame-retardant MXene/polyimide film with outstanding thermal and mechanical properties based on the secondary orientation strategy.

With the development of multifunction and miniaturization in modern electronics, polymeric films with strong mechanical performance and high thermal conductivity are urgently needed. Two-dimensional transition metal carbides and nitrides (MXenes) have attracted extensive attention due to their tunable surface chemistry, layered structure and charming properties. However, there are few studies on using MXenes as fillers to enhance polymer properties. In this paper, we fabricate a three-dimensional foam by the freeze-drying method to enhance the interfacial interaction between adjacent MXene sheets and polyimide (PI) macromolecules, and then a composite film with a dense and well-ordered layer-by-layer structure is produced by the hot-pressing process. Based on the secondary orientation strategy, the resultant MXene/PI film exhibits an enhanced thermal conductivity of 5.12 ± 0.37 W m−1 K−1 and tensile strength of 102 ± 3 MPa. Moreover, the composite film has good flexibility and flame retardancy owing to the synergistic effect of MXene sheets and PI chains. Hence, the MXene/PI composite film with the properties of flexibility, flame-retardancy, high mechanical strength and efficient heat transmission is expected to be used as the next thermal management material in a variety of applications.

An inorganic cross‐linked quadruple shape memory hydrogel with high mechanical performance

AbstractShape memory hydrogels (SMHs) have been the subject of great interest in recent years. However, there were few reports on the simultaneous multiple shape memory and high mechanical performance. Therefore, a novel nanocomposite (NC) hydrogel poly (acrylic acid)/Chitosan/ Laponite (PAA/CS/Laponite) was developed by using Laponite as physical cross‐linker. In order to achieve three temporary shapes, the PAA/CS/Laponite was soaked in iron chloride hexahydrate (FeCl3), sodium hydroxide (NaCl) and sodium hydroxide (NaOH) respectively to (a) form metal coordination; (b) gain the chains entanglement of chitosan; (c) get the microcrystalline structure of chitosan. The maximum shape fixity ratio of PAA/CS/Laponite can reach 100% in 1 minute and it can be restored its original shape within 5 minutes. Moreover, PAA/CS/Laponite showed excellent mechanical performance. The maximum tensile and compressive strengths were 0.73 MPa and 13.1 MPa. By comparison with PAA/CS obtained from our previous work, the tensile strength, elongation at break and compressive strength increased by 2.21 times, 1.46 times, and 3.26 times respectively. Scanning electron microscopy (SEM) showed that the obtained sample has uniform honeycomb network structures which can effectively explain why the gel has strong mechanical performance. These characteristics make PAA/CS/Laponite have huge application potential in reality.

Additive-lathe 3D bioprinting of bilayered nerve conduits incorporated with supportive cells

Nerve conduits have been identified as one of the most promising treatments for peripheral nerve injuries, yet it remains unsolved how to develop ideal nerve conduits with both appropriate biological and mechanical properties. Existing nerve conduits must make trade-offs between mechanical strength and biocompatibility. Here, we propose a multi-nozzle additive-lathe 3D bioprinting technology to fabricate a bilayered nerve conduit. The materials for printing consisted of gelatin methacrylate (GelMA)-based inner layer, which was cellularized with bone marrow mesenchymal stem cells (BMSCs) and GelMA/poly(ethylene glycol) diacrylate (PEGDA)-based outer layer. The high viability and extensive morphological spreading of BMSCs encapsulated in the inner layer was achieved by adjusting the degree of methacryloyl substitution and the concentration of GelMA. Strong mechanical performance of the outer layer was obtained by the addition of PEGDA. The performance of the bilayered nerve conduits was assessed using in vitro culture of PC12 cells. The cell density of PC12 cells attached to cellularized bilayered nerve conduits was more than 4 times of that on acellular bilayered nerve conduits. The proliferation rate of PC12 cells attached to cellularized bilayered nerve conduits was over 9 times higher than that on acellular bilayered nerve conduits. These results demonstrate the additive-lathe 3D bioprinting of BMSCs embedded bilayered nerve conduits holds great potential in facilitating peripheral nerve repair.

Performance enhancement of rubber composites using VOC-Free interfacial silica coupling agent

Nano-silica is an important component for producing elastomer composites used for fabricating “green tires.” However, the poor dispersion of silica particles in the rubber matrix and the emission of volatile organic compounds (VOCs) during the silica modification limit the applications of the modifiers. Here, bis-epoxypropyl polysulfide (BEP), a novel epoxy-type coupling agent, was designed and synthesized for nano-silica modification to cause an interfacial interaction between nano-silica and the rubber matrix and avoid VOC emission. The thermogravimetric analysis result and the bound rubber content show that BEP effectively built a bridge between the nano-silica and the rubber, which led to a strong interfacial effect and promising mechanical performance characteristics. The silica dispersion in solution-polymerized styrene-butadiene rubber (SSBR) was studied using a transmission electron microscope and a rubber process analyzer, and the results demonstrate that BEP could significantly improve silica dispersion. The static and dynamic mechanical performance results indicate that BEP is a valid coupling agent that can achieve silica/SSBR composites with high moduli and reinforcement indices. Moreover, the combination of BEP and bis-(γ-triethoxysilylpropyl)-tetrasulfide (TESPT) was also found to demonstrate a synergistic effect, which resulted in excellent static and dynamic performances of silica/SSBR composites for preparing higher-energy-efficient “green tires.”

Intense shear induced caterpillar-like continuous hierarchical fiber enhanced poly(butylene succinate) biocomposite towards strong mechanical performance

Herein, we used intense shear to construct caterpillar-like continuous hierarchical fibers (CLCHF). This architecture was then modified with mussel inspired poly(dopamine) (PDA) and γ-methacryloxypropyl trimethoxy silane (KH570) in a one-step method. Finally, employing (PDA + KH570)@CLCHF and compounded with poly(butylene succinate) (PBS) ultrafine fiber, (PDA + KH570)@CLCHF/PBS biocomposite was manufactured by combining intense shear and thermal-compression method. In virtue of intense shear, CLCHF can be effectively produced with nanoscale fibrils from 2 nm to 28 nm and (PDA + KH570)@CLCHF and PBS ultrafine fibers displayed favorable homogenization in aqueous solution. More importantly, the interspace between (PDA + KH570)@CLCHF and PBS ultrafine fibers could be optimized to facilitate infiltration at high filler content in polymers. The results also showed that the PBS biocomposite with 30 wt% (PDA + KH570)@CLCHF displayed optimal mechanical performance. Its tensile strength, elastic modulus, flexural strength, flexural modulus and impact strength reached to 120.2 MPa, 6.4 GPa, 110.1 MPa, 4.0 GPa and 23.5 kJ/m2, respectively. It is noticeble that the tensile properties were superior to some previously reported PBS biocompoistes due to the ability of CLCHF to effectively hinder the aggregation of numerous microcracks and slow crack tip propagation. The (PDA + KH570)@CLCHF/PBS biocomposites reported here can be used as desirable substitutes for nondegradable composites due to its high value added and favorable mechanical performance, and may broaden the application prospect of PBS biocomposite.

Customized Kirigami Electrodes for Flexible and Deformable Lithium-Ion Batteries.

Customized deformable lithium-ion batteries (LIBs) have attracted interest in the emerging power systems for flexible and wearable electronics. However, a key challenge for developing these batteries is the fabrication of customized deformable electrodes that exhibit strong mechanical tolerance and robust electrochemical performance during deformation. Here, free-standing customized kirigami electrodes for deformable LIBs are fabricated by an evolutionary printing method with universal viscous electrode inks and a customizable polydimethylsiloxane template. The electrodes comprise lithium iron phosphate or lithium titanium oxide nanoparticles with a conductive carbon nanotubes/poly(vinylidene fluoride) scaffold, which is ideal for electron transfer. The compact microstructure and kirigami pattern endow the electrodes with superior mechanical robustness (over 500 stretch-release cycles) and resistance stability both in unstretched and stretched states. Finite element analysis and corresponding experiment tests reveal ultralow strain inside the materials, showing less than 3% strain even under 100% stretch ratio. With 500-times stretched electrodes, the full-cell LIBs can still deliver a considerable discharge capacity of average 94.5 mA h g-1 at 0.3 C after 100 discharge/charge cycles. The integration of such outstanding mechanical stability, excellent electrochemical performance, and simple printing method with accessible starting materials presents promising opportunities for customizing deformable components for flexible energy storage devices.

Highly thermally conductive and mechanically robust composite of linear ultrahigh molecular weight polyethylene and boron nitride via constructing nacre-like structure

With the rapid development of modern electronic, developing highly thermally conductive and mechanically strong composites for achieving efficient and reliable thermal management has become an urgent task. In this work, boron nitride/linear-ultrahigh molecular weight polyethylene (LUHMWPE) composites with strong mechanical performance and high thermal conductivity (23.03 W/(mK) were fabricated by solid-state extrusion (SSE) method. The thermal conductivity achieved in this work is the highest for bulk polymer so far. The effects of extrusion draw ratio (EDR) on the morphology, structure, and thermal properties were also investigated. With increase in EDR, the original isotropic structure gradually transforms into nacre-like structure due to the extensive elongational flow field during SSE, accompanied by the augment of thermal conduction performance and mechanical properties. We attribute the high thermal conductivity and mechanical properties to the construction of nacre-like structure, where the h-BN platelets and LUHMWPE molecular chains are highly oriented. Our bioinspired composites have potential applications in thermal management field for modern electronics.

Characterization of a Newly Isolated Strain Pseudomonas sp. N3 for Denitrification at Low Temperature

Based on traditional microbiological methods, a novel denitrifier Pseudomonas sp. N3 with excellent denitrification capacity at low temperature was isolated and identified using phenotypic and phylogenetic analysis. Complete nitrate removal was achieved at C/N=8, that is, 70 mg·L-1 nitrate. In addition, the isolate exhibited a great adaptability for low temperature and can reach 100% removal of 15 mg·L-1 nitrate at a temperature as low as 4℃ within 36 h. The denitrification genes of narG and nirS were highly expressed; they were at the same order of magnitude as those at 30℃. Semicontinuous experiments were conducted to test the stability of N3 immobilized with polyvinyl alcohol and sodium alginate at 10℃. The results show that immobilized N3 can remove 15 mg·L-1 nitrate completely within three days and maintains a strong mechanical performance and stability during the whole 54 days. The cold resistance and high denitrification ability of the strain N3 make it applicable to nitrogen wastewater treatment in winter.

UGI 4542 AIR

Abstract UGI 4542 AIR is a martensitic precipitation hardening stainless steel with strong corrosion resistance and high mechanical performance. This datasheet provides information on composition and physical properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1300. Producer or source: Schmolz + Bickenbach USA Inc..