Tensile Strength Research Articles

Antibacterial and wound healing stimulant nanofibrous dressing consisting of soluplus and soy protein isolate loaded with mupirocin

Severe cutaneous injuries may not heal spontaneously and may necessitate the use of supplementary therapeutic methods. Electrospun nanofibers possess high porosity and specific surface area, which provide the necessary microenvironment for wound healing. Here in, the nanofibers of Soluplus-soy protein isolate (Sol-SPI) containing mupirocin (Mp) were fabricated via electrospinning for wound treatment. The fabricated nanofibers exhibited water absorption capacities of about 300.83 ± 29.72% and water vapor permeability values of about 821.8 ± 49.12 g/m2 day. The Sol/SPI/Mp nanofibers showed an in vitro degradability of 33.73 ± 3.55% after 5 days. The ultimate tensile strength, elastic modulus, and elongation of the Sol/SPI/Mp nanofibers were measured as 3.61 ± 0.29 MPa, 39.15 ± 5.08 MPa, and 59.11 ± 1.94%, respectively. Additionally, 85.90 ± 6.02% of Mp loaded in the nanofibers was released in 5 days in vitro, and by applying the Mp-loaded nanofibers, 93.06 ± 5.40% and 90.40 ± 5.66% of S. aureus and E. coli bacteria were killed, respectively. Human keratinocyte cells (HaCat) demonstrated notable biocompatibility with the prepared nanofibers. Furthermore, compare to other groups, Sol-SPI-Mp nanofibers caused the fastest re-epithelialization and wound healing in a rat model. The findings of this study present a novel nanofiber-based wound dressing that accelerates the healing of severe skin wounds with the risk of infection.

From Waste to Strength: A Comprehensive Review on Using Fly Ash in Composites with Enhanced Mechanical Properties

This article explores the diverse applications of fly ash (FA), a by-product generated during the combustion of coal. The introductory segment thoroughly comprehends the origins, composition, and widespread occurrence of FA. FA, which comprises an estimated 38% of worldwide power generation, frequently encounters disposal and storage obstacles on account of its classification as non-hazardous waste in the majority of countries. The environmental issues linked to the dispersal of FA are underscored in the problem statement, which further emphasizes the urgency for sustainable alternatives. Due to the fugitive emissions and potential health hazards associated with metal melting in FA, it is critical to investigate novel applications and disposal techniques immediately. Environmental sustainability is a primary focus of research, with the development of synthetic FA composites being one such alternative. The analysis presents significant findings that underscore the wide-ranging applications of FA. These applications include its utilization as a filler in composites, as well as its incorporation into cement and geo-polymerization processes. Notably, (10-20) wt. % Nano-FA enhances epoxy-based composites, showcasing remarkable improvements in tensile strength, flexural strength, and impact resistance. In thermoplastic composites, substantial enhancements occur within the (5–10) wt. % FA range, but exceeding optimal ranges weakens matrix-fiber interaction, leading to diminishing returns. The article emphasizes the criticality of FA in improving the mechanical and thermodynamic characteristics of substances, specifically within the domain of composites. The investigation into FA nanoparticles, including their processing techniques and surface treatments, unveils encouraging prospects for enhancing material characteristics.

Human Muscle Inspired Anisotropic and Dynamic Metal Ion-Coordinated Mechanically Robust, Stretchable and Swelling-Resistant Hydrogels for Underwater Motion Sensing and Flexible Supercapacitor Application.

Mechanically robust and anisotropic conductive hydrogels have emerged as crucial components in the field of flexible electronic devices, since they possess high mechanical properties and intelligent sensing capabilities. However, the hydrogels often swell on exposure to aqueous medium because of their hydrophilicity, which compromises their mechanical properties. Additionally, the hydrogels' isotropic polymeric networks demonstrate isotropic ion transport, which significantly diminishes the sensing capabilities of electrical devices based on hydrogels. These factors greatly limit their use in flexible and wearable sensors. In this study, we have developed poly(acrylamide-co-maleic acid-co-butyl acrylate) based anisotropic hydrogels by prestretching and drying, followed by ionic cross-linking to fix the alignment. The anisotropic arrangement of the polymer network resulted in significant improvements in mechanical performance and electrical conductivity along the prestretching direction. This anisotropic hydrogel combines hydrophobic and metal ion-ligand interactions, enhancing the maximum tensile strength up to 11 MPa along the prestretching direction, about 3 times higher than in the perpendicular direction. The optimized 200% prestretched hydrogel exhibited high tensile strength (7 MPa), flexibility (fracture strain 370%), high toughness (16 MJ m-3) and antiswelling behavior in water (equilibrium swelling ratio 2% after 15 days). alongside higher conductivity (3 times higher) and strain sensing ability (4 times higher gauge factor) along the prestretching direction. The hydrogel demonstrated efficient and stable underwater sensing for underwater communication and to monitor human limb position and movement. The anisotropic hydrogel electrolyte-based flexible supercapacitor exhibited 117 Fg-1 specific capacitance at 0.5 Ag-1, and maximum energy density 5.85 Whkg-1, significantly higher than the corresponding values for the isotropic hydrogel-based device (88 F g-1 and 4.4 Whkg-1, respectively). This hydrogel mimics the structural design of unidirectionally oriented muscle fibers, showing better direction dependent functional properties than the corresponding isotropic hydrogel. The anti-swelling ability and retention of mechanical and conductive properties of these hydrogels in aqueous environment suggest long-term usage capability of these functional materials.

Optimizing mechanical properties and pioneering biodegradable polymer blends for superior energy-absorbing structures used in sport helmets

Replacing elements made of conventional plastics (like polystyrene) with biodegradable substitutes is part of the trend of sustainable development and waste reduction. The manuscript covers issues related to the design, manufacturing and testing of sports helmet protective inserts made of biodegradable material. The FEM numerical simulations carried out by the authors allowed to determine the optimal desirable mechanical properties (Re = 8.5–65 MPa, E = 500–8000 MPa for 30 × 30 mm inserts; Re = 10.5–60 MPa, E = 500–7500 MPa for 48 × 48 mm inserts; Re = 13–95 MPa, E = 400–8500 MPa for 55 × 55 mm inserts) and geometric parameters (wall thickness equal to 0.2–0.5 mm, height of 20 mm), ensuring the formation of a plastic fold, which is the most effective energy-absorbing mechanism. The conducted quasi-static compression, bending and dynamic tensile strength tests allowed to determine blends with appropriate proportions of durable PLA with more plastic PBAT, PBS and TPS that meet the established criteria: PLA50PBAT50, PLA30PBAT70 and PLA30TPS70.

Tensile strength and durability performances-based evaluation of 3D-printed and mold-cast fibrous geopolymer composites produced at various alkaline activator combinations

This study aimed to investigate the effects of the sodium silicate-to-sodium hydroxide ratio, SH molarity, and carbon fiber volume fraction on the tensile strength and durability properties of mold-cast and 3D-printed geopolymer composites, including flexural and splitting tensile strengths, ultrasonic pulse velocity, water absorption, sorptivity index, and chloride penetration properties. For that purpose, the ground-granulated blast furnace slag and fly ash were employed as alumino-silicate-rich raw material. In order to activate the alumino-silicate-rich raw material, two sodium silicate/sodium hydroxide ratios of 1 and 2 and three sodium hydroxide molarities of 8M, 10M, and 12M were designated. Furthermore, carbon fiber was incorporated into the geopolymer composites at three volume fractions: 0%, 0.3%, and 0.6%. In total, 18 nonfibrous and fibrous geopolymer composites were manufactured in two different ways: mold-cast and 3D-printed. The findings demonstrated that the strength and durability characteristics of 3D-printed specimens were inferior to those of mold-cast specimens, attributed to the presence of weak interfacial bonds between layers. It has been observed that the incorporation of carbon fiber has the effect of improving tensile strength performance. Nevertheless, the addition of carbon fiber led to a slight decrease in UPV values, and an increase in water absorption and sorptivity index values. Also, it adversely influenced the chloride penetration of geopolymer composites. The findings of the study also indicated that increasing the sodium hydroxide molarity had a positive impact on the strength and durability properties of the composites. Nevertheless, it was observed that increasing the sodium silicate-to-sodium hydroxide ratio led to a decrease in both tensile strength and durability performances. Additionally, the microstructure of the geopolymer composites was analyzed using scanning electron microscope (SEM) images.

Experimental and Statistical Investigations for Tensile Properties of Hemp Fibers

This study investigated the tensile behaviors of hemp fiber bundles and examined how properties including tensile strength and Young’s modulus vary with the bundle diameter. Hemp fibers were extracted, degummed, and separated into bundles of different diameters ranging from less than 50 μm to over 150 μm. Tensile tests were conducted on these fiber bundles using a rheometer-based tensile testing machine. The results showed that hemp fibers exhibited a tensile strength of 97.33 MPa and a Young’s modulus of 3.77 GPa at a 50% survival probability. However, the scale parameters for breaking stress and Young’s modulus were determined to be 620.57 MPa and 29.88 GPa, respectively. As the fiber bundle diameter increased, the tensile strength decreased significantly. This was attributed to the higher probability of defects and irregularities acting as weakness points in larger fiber bundles. In contrast, Young’s modulus (stiffness) increased with increasing bundle diameter, likely due to improved fiber–fiber interactions. To further understand the variability and reliability of the tensile properties, statistical models were developed. The Weibull distribution analysis was applied, revealing critical insights into the variability of diameter, stress at break, Young’s modulus, and strain at break. The Weibull parameters provided a comprehensive understanding of the fibers’ mechanical reliability. Additionally, the Griffith model was employed to predict the strength and Young’s modulus based on fiber diameters, supporting the observation that thinner fibers generally exhibited higher tensile strength due to fewer defects. Overall, this work highlights the importance of understanding structure–property relationships in natural fibers like hemp for optimizing their performance in composites.

Automated repair of asphalt pavement cracks and potholes utilizing 3D printing and LiDAR scanning

This study introduces a method for automatic repair of asphalt pavement cracks and potholes using 3D printing and LiDAR scanning. A scanning method was developed to accurately detect and represent cracks and potholes in a 3D model. To address the limitations of LiDAR scanning, such as missing data points caused by the irregular shapes of cracks and potholes, the screened Poisson method was applied to reconstruct the missing data points. These models were validated through both theoretical calculations and sand test. In addition, the research focuses on optimizing key 3D printing parameters, such as printing temperature and printing speed, to enhance performance of crack repair throughout semi-circular bending test. Direct tensile strength test was employed to assess the impact of waste materials (e.g., rubber tire powder and waste glass) on the bond strength of filled sample. The results indicated a volume difference of 2–5 % between the scanning method and the sand test method, demonstrating high accuracy in detecting and reconstructing 3D cracks/potholes. Binders modified with 10 % rubber tire powder, or 20 % waste glass exhibited the highest tensile strength of 212 kPa and 207 kPa, respectively. However, using more than 30 % waste materials is not recommended due to a significant reduction in bond strength compared to conventional binders. An optimal 3D printing speed of 180 mm/min and a temperature of 117 °C are recommended for use in 3D printing in laboratory conditions. It was also noted that higher printing speeds decrease indirect tensile strength, highlighting the importance of balanced parameter settings.

Effect of Testing Mechanisms on the Load-Strain-Time Behavior of Geosynthetic Reinforcements

Abstract This study compares how geosynthetics behave under load, under strain, and over time when subjected to confined tensile tests in soil, employing two commonly used mechanisms in research. One test type simulates a reinforced layer, where tensile loads are indirectly applied to the geosynthetic via stresses transferred from the soil. In contrast, the other test applies tensile loads directly to the geosynthetic material using clamps while under soil confinement. The objective is to elucidate how these testing mechanisms might yield differing in-soil tensile characteristics for different geosynthetics. The study involved conducting load-strain-time tests on samples of nonwoven and woven geotextiles, as well as a geogrid, under varying sustained loads over a 120-h period within a sand clay soil providing soil confinement to geosynthetics at different surcharge levels. The results suggest that soil confinement plays a significant role in shaping the load-strain-time behavior of geosynthetics. Furthermore, it was noted that the impact of testing mechanisms on this behavior is contingent upon the type and stiffness of the geosynthetics, as well as their interaction with the confining soil. In general, in-soil tests in which tensile loads are mobilized by geosynthetics and transferred from the soil provide more confident results for better simulating operation conditions. Tests that directly apply tensile loads to the geosynthetic while maintaining stationary soil confinement may yield misleading results, especially for geosynthetics that have poor interaction with the soil.

Influence of build orientation and heat treatment on high cycle fatigue of additively manufactured AlSi10Mg

This study examines how build orientation and heat treatment affect microstructure and, consequently, the mechanical properties in tensile and high cycle fatigue of additively manufactured AlSi10Mg. Specimens were manufactured in two orientations (0° and 45°) using a laser-based powder bed fusion and subsequently subjected to two heat treatments: (i) direct aging at 170 °C for 2 h (A170) and (ii) stress relief at 300 °C for 2 h (SR300). Two routes for direct aging were previously explored to determine the ideal time and temperature for heat treatment: direct aging at 155 °C and direct aging at 170 °C, both for up to 10 h. It was found that aging at 170 °C for 2 h resulted in higher hardness, yield strength, and ultimate tensile strength than aging at 155 °C for 6 h (A155). The specimens subjected to heat treatment A170 exhibited similar stress amplitude at 106 fatigue life than SR300, with 43.8 MPa and 45.6 MPa, respectively. At similar stress amplitudes, below 106 cycles, the build orientation (0° and 45°) slightly affect the high cycle fatigue properties.

Influence of post-weld rolling and artificial aging on microstructure and mechanical properties of friction stir welded 2195-T4 Al-Li alloy joints

Fiction stir welding (FSW) of a naturally aged (T4) 2195 Al-Li alloy was conducted to study the effect of post-weld artificial aging (AA) and rolling+artificial aging (R+AA) on microstructure and mechanical properties of the FSW joints. Grain features were analyzed by electron back scattered diffraction (EBSD) technology, and precipitates were characterized using transmission electron microscopy (TEM) along [011]Al and [001]Al zone axes. Mechanical properties of the joints were evaluated through micro-hardness and tensile testing. The results indicate that grain development, including grain orientation, grain boundary components and dislocation density, varies within different regions of the As-welded joints due to complicated thermal-mechanical history. The alloying elements mostly exist as Guinier-Preston zones in the base material (BM) with a few formations of δ'/β', and slightly precipitate into T1 in the heat affected zone (HAZ), form σ in the thermal-mechanical affected zone (TMAZ), as well as develop T1 and S' in the nugget zone (NZ) after FSW. The lowest hardness zone (LHZ) exhibits elevated precipitation levels, generating coarse T1 and grain boundary precipitates with evident σ and precipitate free zone. The overall precipitation level of the As-welded joints remains minor, resulting in a slight decrease in hardness at the LHZ. Post-weld AA promotes many T1 formations, enhancing the joint strength and hardness. As a result, the ultimate tensile strength (UTS) of the joints increases from 440 MPa to 506.5 MPa, while the elongation decreases from 13.5% to 3.4%. Furthermore, hardness profiles transform from a low-amplitude wave curve to a high-amplitude W-shaped curve, generating a significant LHZ due to the minimal precipitation of T1. Pre-rolling deformation can enhance dislocation density and low angle grain boundaries (LAGBs), promoting the nucleation of high-density, fine T1 during artificial aging, and especially improves precipitation ability of the LHZ, leading to an elevated hardness increment in the region after AA. Compared to the Joint-AA, both strength and elongation of the Joint-R+AA increase, obtaining 530.5 MPa and 3.9%, respectively.

Increasing the high-temperature mechanical properties of Mg-Gd-Y-Zn alloys by adding AlN/Al particles

The AlN particles reinforced Mg-10Gd-3Y-1Zn (GWZ) composites were prepared by mixing AlN/Al particles using ball milling followed by stirring casting method. The influence of AlN/Al particles on the microstructural evolution and high-temperature mechanical properties of GWZ alloys were revealed and discussed. With AlN/Al particles added into the as-cast alloys, the Mg3RE phase was transformed into lamellar LPSO phase, while the content of Al2RE and LPSO phase increased. Since the Al2RE and AlN were effective nucleation sites for α-Mg, the grain size of AlN/Al-GWZ composites was reduced obviously from 126.1 to 39.8 μm. After homogenization, due to the coherent lattice matching relationships between 18R-LPSO phase and Al2RE or AlN particles, the 18R-LPSO phase nucleated on the Al2RE and AlN particles. After ageing treatment, the 2AlN/Al-GWZ composite showed the optimum mechanical properties at 250 °C, with the yield strength, ultimate tensile strength and elongation of 247.1 MPa, 265.5 MPa and 4.0%, respectively. The strengthening effect was primarily originated from the AlN particles, Al2RE and LPSO phases in the 2AlN/Al-GWZ composite. Besides, the composites can achieve the enhancement of high-temperature strength without the sacrifice of plasticity due to the coordinated deformation of AlN particles as well as the refinement of grains.

Achieving microstructural homogeneity in the stir zone across thick AA6061 welds using self-reacting bobbin tool friction stir welding

This study focuses into strategizing the usage of self-reacting bobbin tool friction stir welding (SRBT-FSW) to obtain consistent microstructural homogeneity along the thickness of AA6061 aluminium alloy (AA) thick plates during welding. The SRBT-FSW technology, distinguished by its dual-shoulder design, represents a significant step forward in FSW by eliminating the requirement for a backing anvil and promoting balanced heat distribution. This study seeks to address the issues of maintaining uniform microstructural characteristics throughout the weld zone, which is crucial for the mechanical performance and durability of welded joints in structural applications. The experimental study entails the systematic welding of AA6061 plates of 6 mm thickness using a self-reacting bobbin tool under a fixed processing condition. Electron backscatter diffraction (EBSD) was used to characterize the grain structure and phase distribution over the weld. Mechanical parameters like as tensile strength and hardness were determined to establish correlations between microstructure and mechanical performance. The results demonstrated that SRBT-FSW significantly enhances microstructural homogeneity across the weld zone, leading to improved mechanical properties. In the Bottom Zone (BZ), a refined grain structure with an average grain size (AGS) of 3.53 µm and a random or weak texture was observed, contributing to enhanced hardness and mechanical performance, with an ultimate tensile strength (UTS) of 220 MPa. In contrast, the Top Zone (TZ) exhibited a coarser AGS of 4.33 µm with a pronounced {111} crystallographic texture, resulting in a slightly lower UTS of 205 MPa. The Middle Zone (MZ), influenced by the greater heat input from both the TZ and BZ, showed an intermediate AGS of 3.99 µm, predominantly oriented along the {101} plane, and achieved a UTS of 194 MPa, with a slight reduction in ductility. This study highlights the potential of self-reacting bobbin tool friction stir welding as a reliable method for making high-quality, homogeneous welds in thick aluminium plates and paving way for their wider application in the aerospace, automotive, and shipbuilding industries, where homogeneous microstructural qualities are of significant importance.

Grain boundary migration hysteresis during recrystallization of IN738LC alloy fabricated via laser powder bed fusion

The metastable microstructure formed during laser powder bed fusion (LPBF) significantly influences recrystallization behavior, which is crucial for flexible control of microstructure. To investigate these effects, various IN738LC alloys were fabricated by adjusting the volume energy density (VED) and then subjected to the same hot isostatic pressing (HIP) treatment. The microstructures before and after heat treatment were systematically analyzed using multi-scales characterization methods. The results indicate that the recrystallization fraction in HIP-treated samples decreased from 75% to 24% as the VED increased from 53 J/mm3 to 125 J/mm3. This reduction is primarily attributed to the increased grain boundary migration hysteresis caused by the higher density and larger diameter of MC-type carbide particles (i.e., MC particles). Subsequently, these HIP-treated samples were further processed using standard heat treatment (SHT) to evaluate their tensile properties at 23 °C and 900 °C. At 23 °C, the sample with the lowest recrystallization fraction (VED = 125 J/mm3) exhibited the best combination of strength and ductility, with an ultimate tensile strength (UTS) of 1422 MPa, yield strength (YS) of 932 MPa, and elongation of 21%. At 900 °C, the sample with a medium recrystallization fraction (VED = 75 J/mm3) demonstrated the best combination of strength and ductility, with an UTS of 626 MPa, YS of 420 MPa, and elongation of 15.5%.

Full bio-based flame retardant towards multifunctional polylactic acid: Crystallization, flame retardant, antibacterial and enhanced mechanical properties

The preparation of flame-retardant high-performance polylactic acid (PLA) composites by adding green flame retardants have always been a challenge. In this work, an intumescent flame-retardant PCR based on phytic acid, chitosan, and resveratrol was successfully designed. Adding 4 wt% of PCR, the PLA-PCR composite was classified as UL-94 V-0 grade, with a LOI value increasing from 19.7 % (pure PLA) to 26.0 %, a peak heat release rate decreasing from 433 to 344 kW/m2. Owing to excellent compatibility of PCR, the mechanical strength and toughness of PLA-PCR composites have been improved, as reflected by a ~ 16 % increase in tensile strength, a ~ 73 % increase in impact strength and a ~ 57 % increase in toughness. In addition, PCR also presented plasticization effect on PLA, making it easier to process. This work provided a highly efficient and environmental-friendly modification approach for the development of multifunctional polymers.

Preparation and performance comparison of low‐dielectric epoxy resins cured by naphthalene‐ and phenyl‐based active esters

AbstractThe poor dielectric properties of epoxy resins limit their application in microelectronics, and active ester curing agent is an effective means to enhance the dielectric properties of epoxy resins. However, the phenyl active ester curing resins nowadays have the problem of low mechanical properties. In this work, a novel naphthalene‐based active ester‐cured resveratrol epoxy resin system (REP/NDA) was prepared for the first time. Compared with the phenyl‐active ester‐cured epoxy resin (REP/PDA), the naphthyl‐active ester prepared epoxy resin has obvious advantages in mechanical properties. The experimental results indicated a tensile strength measurement for REP/NDA at 91.9 MPa, the tensile strength of REP/PDA was 65.3 MPa, and the tensile strength of REP/NDA was 141% of that of REP/PDA. The prepared REP/NDA epoxy resin exhibits favorable dielectric properties, evidenced by a dielectric constant of 3.02 at 10 MHz and a dielectric loss of 0.0042, very good thermal stability (T5% of 379°C), excellent water absorption (only 0.49% for 7 days from 2 to 8°C) and good dimensional stability (coefficient of thermal expansion below Tg of 77 ppm). The first synthesis of naphthalene‐based active ester curing agent offers a reference for creating new low dielectric epoxy resin materials that work out exceptionally.

Robust, transparent, self-healable, recyclable all-starch-based gel with thermoelectric capability for wearable sensor

Conventional all-starch-based (ASB) gels are weak and lack ductility. The preparation of a robust ASB gel with multi-functionalities e.g., self-healing, anti-freezing, conductivity, and so forth, is highly desirable but challenging. Herein, a new kind of ASB gel was prepared by gelatinizing starch in urea and choline chloride solution (UC) with the aid of water. Its tensile strength was up to 1.08 MPa with a tensile strain of 313 %, and this value hardly changed after 10 days ageing. A high healing efficiency of 98 % can be achieved after 1 h of healing at room temperature, and the healed tensile strength reaches up to ca. 1.06 MPa, which is almost the highest value for ASB gel. The resultant ASB gel can surfer from bending and twisting at −80 °C. Moreover, ASB gel also exhibits excellent biocompatibility and biodegradability. In addition, UC endowed the ASB gel with ion conductivity, allowing it to be used as a flexible strain sensor to monitor human movement. The ion-conductive ASB gel also exhibited thermoelectric ability with a Seebeck coefficient of 2.5 mV K−1, which can be further improved to 5 mV K−1 with a maximum output voltage of 252 mV by introducing a gradient of ionic concentration.

Dewatering and drying of Kombucha Bacterial Cellulose for preparation of biodegradable film for food packaging.

Kombucha Bacterial Cellulose (KBC), obtained from waste products of kombucha fermentation, has potential applications in diverse fields. The present study used tea waste as a raw material for producing kombucha-like beverages and bacterial cellulose (BC). The in-situ dewatering and drying operations were performed to remove the high-water content from fermented KBC. Herein, the performance of BC in pressure-driven separation has been investigated as a function of dewatering pressure, drying temperature, and drying time in a multifunctional filtration cell. The Central Composite Design (CCD) was used to optimize the dewatering and drying parameters. The optimum conditions were found to be 4bar pressure, 99°C drying temperature, and 5min drying time with a desirability value of 0.921. The predicted response values agreed with actual responses within 2.3-2.7%. The dried films were prepared at optimized conditions and used to investigate thickness, density, mechanical properties, Fourier transform infrared, and scanning electron microscopy. The properties of KBC film varied as fermentation days increased. The KBC films' transparency decreased as thickness and density increased. The KBC film exhibits excellent mechanical properties such as tensile strength, maximum load, extension at the break, load at the break, and Young's modulus. The KBC films have been reported to be biodegradable and non-toxic and may be used for food packaging. Moreover, the present study successfully demonstrated that KBC packaging material could extend the shelf life of tomatoes by 13-15days under accelerated conditions.

Modification of Bamboo Fiber for Reinforcing Cement-based Composites and Durability Improvement

This study tackled the issue of inferior fiber-matrix adhesion in bamboo fiber (BF) reinforced cement-based composites, a critical factor impacting their performance and service life. Our approach introduces a novel application of silane coupling agents (SCAs) to improve the compatibility of BF with cement matrices. We utilized isocyanate propyl triethoxy silane (IPTS) in a pioneering manner, and used γ-glycidyl ether oxypropyl trimethoxysilane (KH560), respectively, to chemically modify the BFs. This modification strategy was designed to enhance the adhesion between BFs and the cement matrix through the SCAs' interaction with hydroxyl groups on the BF surface and their involvement in the cement hydration process. Our findings reveal that the modified BFs, when incorporated into cement composites, not only match the compressive strength of the control but also show a remarkable increase of over 20% in flexural strength and over 30% in tensile strength. Additionally, the modified BFs reduce drying shrinkage by more than 19% after 90-day curing, and similarly significant reductions are observed in chloride ion penetration and freeze−thaw cycle failure rates. Notably, IPTS outperforms KH560 in enhancing mechanical strengths and durability, likely due to the formation of more siloxane bonds on the fiber surface, leading to stronger cement matrix interaction. This research presents a cost-effective method to improve the performance of BF/cement composites, paving the way for broader utilization of BFs in sustainable construction materials.

Microstructure and mechanical properties of high-strength Al-Zn-Mg-Ni alloys with excellent twin-roll castability

This paper proposes a new high-strength Al-Zn-Mg-Ni alloy with excellent twin-roll castability compared with conventional Al-Zn-Mg-Cu alloys. Thermodynamic calculations were carried out to identify the solidification range and amount of residual liquid phase in the Al-Zn-Mg-(Cu, Ni) alloys, which are factors exerting significant influence on the formation of defects in the final strips. The designed Al-Zn-Mg-Ni alloys exhibited a narrower solidification range and smaller amount of residual liquid at the final solidification temperature, resulting in excellent surface quality after twin-roll casting compared with Al-Zn-Mg-Cu alloys. A series of rolling and heat treatment processes was performed on the Al-Zn-Mg-Ni alloy strips, and the mechanical properties of the final sheets were evaluated. The results showed that the yield and tensile strength were increased without affecting the elongation up to approximately 1.0wt.% Ni addition. Additionally, compared with conventional Al-Zn-Mg-Cu alloys, equivalent or higher tensile properties were achieved after T6 tempering. In conclusion, the Al-Zn-Mg-Ni alloy exhibits high-strength with excellent twin-roll castability.

Hyaluronic acid-based ε-polylysine/polyurethane asymmetric sponge for enhanced wound healing

Asymmetric sponge dressings with a hydrophobic surface and a hydrophilic inner layer can prevent bacterial infiltration and ensure efficient absorption of wound exudate. In this work, ε-polylysine/aliphatic polyurethane sponge (EPU) was prepared by prepolymer foaming process, and oxidized hyaluronic acid (OHA) was cross-linked with ε-polylysine (EPL) in EPU through schiff-base reaction to obtain EHPU. Octaisobutyl polyhedral oligomeric silsesquioxane (Oi-POSS) was uniformly sprayed onto the surface of EHPU as the hydrophobic layer, resulting in asymmetric sponge dressings denoted as P-EHPU. These dressings demonstrate capabilities in resisting staining and bacterial invasion, with internal EPL effectively inhibiting bacterial proliferation on the wound surface. The introduction of OHA and EPL leads to a denser and more complete pore structure of the sponge, endowing it with good compression, tensile strength, and hemostatic performance. Wound healing studies indicate that P-EHPU effectively prevents external bacterial infiltration and promotes wound healing.