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Foamed silicone rubber was prepared by mixing 45% vinyl silicone oil (Base), Karstedt platinum catalyst (Cata), and hydrogenated silicone oil (SiH) and the resulting material was subjected to secondary vulcanization, which led to its performance requirements. Vinyl silicone oil and hydrogenated silicone oil underwent an addition reaction under the action of a platinum catalyst to form an elastomer with a cross-linked network structure. The results showed that by increasing the content of hydrogenated silicone oil in the formulation, the elongation at break of the foamed silicone gel material decreased but the tensile strength increased. When the content of hydrogenated silicone oil in the formulation decreased, the elongation at break of the foamed silicone material increased. When the content of Karstedt catalyst in the formulation increased, the formation time of the reaction gel was greatly shortened, and the cell structure tended to be dense but delicate. When the proportion of vinyl silicone oil in the formulation increased, the elongation at break of the foamed, molded silicone rubber increased. However, the elastic modulus decreased, and the thermal stability improved. Finally, a more suitable formulation of VBase:VCata:VSiH = 32:1:2 was obtained, which showed a tear resistance of 5.52 KN/m, ductility of 133%, and limiting oxygen index of 26 with a stability temperature of 346.8 °C when the thermal mass loss reached 95%. [ABSTRACT FROM AUTHOR]

In this article, waste fibres from the recycling tire process with a different percentage of addition (0, 2.5, 5, 7.5, 10, 12.5) were mixed to increase their tensile strength, tear resistance, and bending resistance with natural rubber NR. The effect of short fiber on composite mechanical properties was investigated. Despite substantial research on the mechanical characteristics of rubber products reinforced with fiber waste, the experimental work focused on identifying precursory physical mechanisms that are responsible for fracture behavior during tests and structural monitoring. The findings reveal that milling and vulcanization conditions have a significant role in enhancing mechanical characteristics. The waste fibres and natural rubber provide strong interfacial adhesion during two rolls of milling and vulcanization at 140°C. Waste fiber may boost the tensile strength of a composite material by up to 7.5% of waste fiber, with a slight decrease at 10% and 12.5%. The flexing test findings showed that adding fiber to the recipe improved it by up to 7.5% before gradually degrading, and it is obvious that the recipes' tear resistance improves in comparison to the basic recipe. The discoveries have the potential to increase the tensile strength, tear resistance, and flexing resistance of industrially manufactured rubber conveyor belts, which are important physical properties in engineering applications. [ABSTRACT FROM AUTHOR]

The influence of the abrasive particle size and modifiers (low molecular weight liquid rubbers (LMWRs), sulfidosilane) on the rate of wear on abrasive paper of rubbers based on natural rubber (NR), carbon black (CB), and polyoxadiazole (POD) fiber is studied as a function of structure and mechanical properties of rubbers. Model rubber blends were prepared in a closed-type mixer, the abrasive wear tests were conducted on a drum-type machine, the structure and the mechanical properties of rubbers were characterized by DMA, static tensile tests, hardness measurements, and tear resistance. The wear surfaces were analyzed by SEM. Tests have shown that the addition of fiber does not affect the rate of abrasive wear of the original NR/CB rubber regardless of the grain size of the abrasive. Addition of modifiers that increase tensile modulus M10, hardness HSh, tear resistance TR, tensile strength A, and degree of crosslinking γ reduces the wear rate under friction on coarse abrasive, which is characteristic of abrasive wear with a predominance of micro-cutting. The greatest influence, judging by the value of the correlation coefficient, is exerted by the value of M10, dependent on the bond strength between the matrix and the fiber, which allows predicting the wear rate of rubbers based on the results of mechanical tests. When worn on a fine abrasive paper, the increase in M10, HSh, TR, and γ on the contrary, raises the wear rate of rubber, and the tensile toughness has practically no effect on it. This is attributed to the predominance of the fatigue wear mechanism, in which the wear rate increases with contact stresses, in proportion to the strength properties, with tear resistance exerting the greater effect on the wear rate. [ABSTRACT FROM AUTHOR]

This research focused on the tanning of sheepskins (Ovis aries) using tannins extracted from mango kernels (Mangifera indica) to assess the potential of this byproduct. Tannin extractions were conducted using ethanol-water solutions at concentrations of 70%-30% and 50%-50%. Quantification was performed via the Folin-Ciocalteu method using gallic acid as a standard. The tanning ability on sheepskin was evaluated through the leather's physical properties. The highest concentration of gallic acid equivalents (GAE) was obtained from the ethanol-water extraction at 50%-50%, with an average concentration of 110,1 mg GAE/g. Subsequently, the tanning process was applied to sheepskin, and the physical-mechanical properties of the leather were determined. Tensile strength values obtained were 12,7 MPa for the 50%-50% ethanol-water concentration and 11,3 MPa for the 70%-30% ratio. Elongation percentages were 11,7 N and 17,7 N, tear resistance values were 41,9 N and 58,0 N, shrinkage temperatures were 61°C and 60°C, distension measurements were 13,2 mm and 10,6 mm, and breakage forces were 37,4 daN and 48,3 daN respectively. Ultimately, the tanned leathers with tannins met 5 out of 6 analyzed tests according to UNE-EN ISO standards. Hence, the tannin extract from mango kernels demonstrates potential as a substitute for chromium salts, thereby favoring both environmental sustainability and the production of quality leather from sheepskin. [ABSTRACT FROM AUTHOR]

The present study encompasses the utilization of a mixture of 1-butene and 1-hexene comonomers for the large-scale production of a film-grade linear low-density polyethylene (LLDPE) resin. The goal involves assessing the impact stemming from the partial replacement of 1-butene with 1-hexene on the thermal, physical, mechanical and rheological properties of the resultant resin, juxtaposed against an LLDPE counterpart exclusively produced by 1-butene as the comonomer. Although the comprehensive examination of key physical, thermal, rheological and mechanical characteristics indicates nominal influence due to the substitution, a marked escalation materializes in both the tear resistance and slow crack growth (SCG) resilience of the LLDPE resins formulated through the amalgamation of these comonomers. Specifically, the tear and SCG resistance of the proposed resin exhibit an extraordinary surge exceeding 60% and 30%, respectively. This discernible enhancement underscores the viability of the proposed technique as a propitious avenue for augmenting the requisite mechanical properties, obviating the need for an all-encompassing shift from 1-butene to longer-chain α-olefin comonomers. [ABSTRACT FROM AUTHOR]

A high-purity octamethylcyclotetrasiloxane (D4 ) with low metallic impurity was prepared by adding ethanol and a small amount of crown ether by solidification, filtration and distillation. After alkali catalyzed ring opening polymerization and end capping reaction, the low volatile vinyl and methyl terminated methyl vinyl silicone rubber were prepared with tetramethyldivinyldisiloxane and silicone oil as the end capping agents, respectively. The formula of silicone rubber (Shore A hardness 40 and 70) with high tear resistant and elastic resilience were discussed. The results show that the proper formula for silicone rubber with Shore A hardness 40 was that 85 phr of 110 polysiloxane with vinyl mole fraction of 0. 03%, 15 phr of 110 polysiloxane with vinyl mole of 0. 08%, 31 phr of fumed silica with 380 m2 / g, and 5 phr of hydroxyl silicone oil, 0. 1 phr of zinc stearate, and 3 phr of 112 polysiloxane with vinyl mole of 3%. The prepared silicone rubber showed Shore A hardness of 42, tensile strength of 11. 0 MPa, elongation at break of 980%, tear strength of 38 kN/ m, elastic resilience of 74. 8%, volatile of 0. 8%, and the mass fraction of n-hexane extracts of 1. 5%, which was ideal for the production of Foley catheter negative pressure ball. The proper formula for silicone rubber with Shore A hardness 70 was as follows: 55 phr of 110 polysiloxane with vinyl mole of 0. 08%, 42 phr of 110 polysiloxane with vinyl mole of 0. 23%, 3 phr of 112 with vinyl mole of 3%, 42 phr of fumed silica with specific surface area of 380 m2 / g, 8 phr of hydroxyl silicone oil, 5 phr of methoxy silicone oil, 0. 1 phr of zinc stearate, 0. 5 phr of hydrogen containing silicone oil with active hydrogen mass of 0. 5%, and 5 phr of polyvinyl silicone oil. Thus the silicone rubber has Shore A hardness of 70, tensile strength of 8. 1 MPa, telongation at break of 540%, tear strength of 46 kN/ m, elastic resilience of 71. 5%, volatile of 1. 2%, and n-hexane extracts of 1. 6%, which can be used on Foley catheter, throat or drainage tube. [ABSTRACT FROM AUTHOR]

In the introduction, we present an overview of previous research on this subject in order to help the reader review possible technological solutions regarding the joining of construction materials. The original research presented in this article concerns the results of increasing the shear strength of adhesive joints of plastics using various types of surface preparation (laser texturing). Laser texturing consists in developing the surface by applying various geometric patterns of appropriate shapes and depths, as well as its density on the surface. The above parameters are currently selected in an empirical way as research is still being developed as part of a research project. The textures obtained in this way are subjected to microscopic examination. Then, a layer of glue is applied, and the samples prepared in this way, after drying, are subjected to various destructive tests, e.g., tensile, shear, and bending. In this article, we attempted to test the strength of the bonded joint of polyethylene (PE). The impact of a laser beam with ultrashort picosecond pulses was used in the research. Tools in the form of a TRUMPF TruMicro 5325c device integrated with a SCANLAB GALVO scanning head were used. This enabled ablative material removal without the presence of a heat affected zone (HAZ) in the non-laser part. Ultrashort laser pulses remove material without melting the non-exposed area by the laser beam. On the basis of the tests performed (in this article and previous research works of the authors), it was shown that the method increases the shear strength of the glued joints made in the tested construction materials. This is confirmed by laboratory results of tribological tests. The laser treatment parameters used, which are shown in this article, did not lead to the appearance of cracks in the micromachined materials. Research has shown that the connections between elements with a properly selected micropattern are characterized by a several-fold increase in the strength of joints, unlike materials without a micropattern. The presented method may be helpful for use as a technology for joining plastics. [ABSTRACT FROM AUTHOR]

This study examines the resistance of three-dimensional (3D) weft-knitted fabrics to mechanical risks to determine the influence of varying percentage contents of high molecular weight polyethylene and basalt on cut, puncture, abrasion, and tear resistance. The three-dimensional weft-knitted fabrics are designed by separating functional layers: the outer (protective) layer contains varying percentage contents of high molecular weight polyethylene and basalt; the inner layer (suitable for contact with the skin) contains polyester; both layers are connected using polyamide. The strength properties of knits in response to mechanical impact were evaluated by performing cut, puncture, abrasion, and tear resistance tests. Basalt was found to improve the cut resistance of knits significantly, even with its content as low as 5% in the outer layer. The knit with the highest high molecular weight polyethylene content in the outer layer demonstrated the best puncture and tear resistance. No correlation was established between the varying percentage contents of high molecular weight polyethylene and basalt and the maximum number of abrasion cycles, as the three-dimensional weft-knitted fabrics showed no noticeable wear. The test results show that the structure of three-dimensional weft-knitted fabric with the outer layer designed to withstand mechanical impact and the inner layer suitable for direct contact with the skin protects against a wide range of mechanical impacts. This applies even when varying percentage contents of high molecular weight polyethylene and basalt are used only in the outer layer. [ABSTRACT FROM AUTHOR]

Rubber products generally need to have high resistance to abrasion, tear, and cutting. Filling short fiber with strong mechanical properties and forming a net in the rubber matrix is a good method to realize the above aims. In this article, ultra-high molecular weight polyethylene (UHMWPE) short fibers with a diameter of 20 μm and a length of 2 cm were filled into natural rubber (NR) to improve the tear strength of the NR. The influence of the short fiber mass fraction and vulcanization conditions on the mechanical properties of the composites were investigated. The results show that the milling process and vulcanization conditions are key factors in enhancing tear resistance performance. Double-roll milling and vulcanization at 143 °C for 40 min result in strong interfacial adhesion between the UHMWPE short fibers and the NR. The addition of 2 phr of UHMWPE fiber increases the tear strength of the composite material by up to 150.2% (from 17.1 kN/m to 42.8 kN/m) while also providing excellent comprehensive performance. Scanning electron microscope (SEM) imaging confirmed that the UHMWPE short fibers are dispersed in the NR matrix homogeneously, and the interface is close and compact. As a control experiment, UHMWPE resin powder was directly filled into the NR, and then the composite was vulcanized using the same process as that used for the NR/UHMWPE short fiber composite. The results show that the mechanical strength of the NR/resin powder composite exhibits minor improvement compared with NR. As there is no complicated surface modification of the UHMWPE fiber, the results reported may be helpful in improving the tear resistance of the industrially prepared rubber conveyor belts. [ABSTRACT FROM AUTHOR]

In this study, the poly(lactic acid) (PLA)/poly(butylene adipate‐co‐terephthalate)(PBAT) blend is investigated to improve rheological and mechanical performances of PBAT based on rheological, mechanical, and thermal behavior analyses. The multi‐step mixing method is developed to fabricate the blend with non‐spherical morphology. In the multi‐step mixing method, blends with a wide composition range (25/75–75/25) are mixed with additional PBAT at a mixing temperature between the melting temperatures of PBAT and PLA to produce the PBAT blend embedded with non‐spherical PLA particles (10 wt%). The embedding of non‐spherical PLA particles in PBAT increases the resistance against deformation, resulting in strain hardening behavior and an increase in the yield strength as well as the tear resistance of the PBAT. The presence of stiff PLA particles enhances the crystallization behavior of PBAT, meaning that polymer chains may interpenetrate. The findings of this study suggest that the multi‐step mixing method is beneficial for embedding non‐spherical PLA particles into a PBAT matrix, which in turn facilitates the maintenance of good interfacial adhesion to increase the melt strength, yield strength, and tear resistance. [ABSTRACT FROM AUTHOR]

This study investigates the resistance of three-dimensional (3D) weft-knitted fabrics to mechanical risks in order to determine the impact of the percentage content of raw materials in the knits on mechanical loads. For this purpose, 3D weft-knitted fabrics, consisting of a front side, binding, and back side layers, were designed and produced on an E20 circular weft-knitting machine using organic multifilament yarns (high molecular weight polyethylene, HMWPE) and inorganic multifilament (basalt, BS) yarns for the front and back side layers and conventional polyamide yarns for the binding layer. The cut, puncture, abrasion, and tear resistance tests were performed to assess the resistance of 3D weft-knitted fabrics to mechanical risks. According to the testing results, basalt in the structure of 3D weft-knitted fabrics significantly increases the cut resistance, even in cases of a small basalt content in the knit. The puncture, abrasion, and tear resistance testing results showed that the highest HMWPE percentage content in the knitted structure provided the highest resistance to these risks, while increasing the basalt content in the knit did not improve the resistance testing results. Based on the testing results and the assessment of the protection levels provided by the knitted fabrics, the conclusion can be made that the use of HMWPE multifilament yarns and basalt multifilament yarns in the structure of 3D weft-knitted fabrics contributes to the achievement of the highest levels of performance. All the designed 3D weft-knitted fabrics provide complex protection against different mechanical risks (cut, puncture, abrasion, tear). The tests performed may be useful for further development of knitted fabrics designed to provide protection against mechanical risks. [ABSTRACT FROM AUTHOR]

• A new elastomer structure with three elements（soft-hard-rigid）was synthesized. • The synergistic effects of three elements cause outstanding mechanical properties. • Outstanding toughness endows elastomer excellent tear and wear resistance. • New structure overcomes the difficulty of coexistence of strength and toughness. In materials science, achieving polymers that possess both high strength and high toughness—traditionally seen as contradictory properties—remains a significant challenge. In this study, a poly (urethane-imide-urea) (PUIU) was synthesized, featuring soft, hard, and rigid segment groups alternately distributed along the main chain. By integrating a polyurethane (PU) prepolymer, urea, and imide, with the PU prepolymer acting as the soft segment to confer malleability, urea-formed hydrogen bonds serving as the hard segment to provide toughness, and imide acting as the rigid segment to enhance material strength. The synergistic effects of these elements result in an elastomer with outstanding strength (70.1 ± 2.6 MPa), high elongation at break (1813.9 ± 76.0 %), and high toughness (420.4 ± 22.3 MJ/m3). Furthermore, it demonstrates superior fatigue, tear, and wear resistance. Through a blend of simulation and experimentation, we uncover the reasons behind its high performance. This study demonstrates the feasibility of preparing an elastomer that combines softness, hardness, and rigidity, meanwhile, achieving a balance between strength and toughness, thereby offering valuable theoretical guidance for the integration of high strength and high toughness. [ABSTRACT FROM AUTHOR]

Photocurable gels have broad application prospects in biomedicine, bionics, flexible wearable devices and other fields. However, there are still some problems in the current photocurable gels, such as notch sensitivity, that is, poor tear resistance. In this study, we provided a photocurable gel with excellent tear resistance. The gel prepolymer is mainly composed of hydroxymethylacrylamide (NAM) and cellulose nanocrystals (CNC) modified with dopamine hydrochloride (DA), referred to as DA@CNC. After photocuring, the prepared gels show excellent mechanical properties such as tear resistance, elasticity and toughness. The introduction of DA@CNC not only endows gels with a large amount of energy dissipation through hydrogen bond crosslinking, but also effectively resists crack expansion as a nano-sized reinforcing phase, which greatly improves the tear resistance of the gels. Even at a 40 % gap, the elongation at break of the gel can still reach 1445 %. In addition, the DA can endow the gel with good electrical conductivity and excellent sensitivity (GF = 23.8). Some flexible wearable devices like finger sleeve and wristband can be customized by photocurable 3D printing using the gel with high toughness. This high-performance gel has great application potential in flexible wearable devices., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Rubber products generally need to have high resistance to abrasion, tear, and cutting. Filling short fiber with strong mechanical properties and forming a net in the rubber matrix is a good method to realize the above aims. In this article, ultra-high molecular weight polyethylene (UHMWPE) short fibers with a diameter of 20 μm and a length of 2 cm were filled into natural rubber (NR) to improve the tear strength of the NR. The influence of the short fiber mass fraction and vulcanization conditions on the mechanical properties of the composites were investigated. The results show that the milling process and vulcanization conditions are key factors in enhancing tear resistance performance. Double-roll milling and vulcanization at 143 °C for 40 min result in strong interfacial adhesion between the UHMWPE short fibers and the NR. The addition of 2 phr of UHMWPE fiber increases the tear strength of the composite material by up to 150.2% (from 17.1 kN/m to 42.8 kN/m) while also providing excellent comprehensive performance. Scanning electron microscope (SEM) imaging confirmed that the UHMWPE short fibers are dispersed in the NR matrix homogeneously, and the interface is close and compact. As a control experiment, UHMWPE resin powder was directly filled into the NR, and then the composite was vulcanized using the same process as that used for the NR/UHMWPE short fiber composite. The results show that the mechanical strength of the NR/resin powder composite exhibits minor improvement compared with NR. As there is no complicated surface modification of the UHMWPE fiber, the results reported may be helpful in improving the tear resistance of the industrially prepared rubber conveyor belts.

Background: In this study, the tear resistance of porcine lens capsules after continuous curvilinear capsulorhexis (CCC) and femtosecond (fs)-laser-assisted capsulotomy for cataract surgery (FLC) with different laser parameters is measured with a custom-made testing setup. Methods: Forty-five fresh porcine lenses were randomly chosen for CCC (n = 15) or FLC 1 (n = 15) and FLC 2 (n = 15). The FLC 1-group was treated with smaller spot distances than the FLC 2-group. The force necessary to break the opening of the anterior capsule and the maximum displacement were measured. Results: The mean tear resistance of the CCC-group (150 ± 70 mN) was higher than that of the FLC 1-group (60 ± 20 mN) and the FLC 2-group (30 ± 20 mN). Conclusion: It could be shown that CCC leads to a significantly higher tear resistance of the opening than FLC in porcine lenses. The femtosecond laser group demonstrated that smaller spot distances lead to a higher tear resistance. [ABSTRACT FROM AUTHOR]

This study proposes a manufacturing method for reproducing some physical properties of the heart by comparing the elasticity, tear resistance, and hardness of a pig heart and three-dimensional printing materials, Agilus and Tango. A Digital Force Gauge was used to analyze elastic modulus and tear resistance, whereas a Shore A hardness meter was used to measure hardness. Agilus and Tango had 10 and 5 times higher elasticity, respectively, 2 and 4 times higher tear resistance, and a higher Shore A hardness than the pig heart. In summary, the pig heart had a more similar elasticity and Shore A hardness than the Tango sample, whereas more tear resistance was similar to the Agilus sample. Therefore, we proposed elasticity and tear resistance equations that can be used to build a heart model and a conversion table for heart fabrication at various thicknesses. [ABSTRACT FROM AUTHOR]

The mechanical properties of ionic conductive hydrogels (ICHs) are generally inadequate, leading to their susceptibility to breakage under external forces and consequently resulting in the failure of flexible electronic devices. In this work, a simple and convenient strategy was proposed based on the synergistic effect of ion cross-linking and salting out, in which the hydrogels consisting of polyvinyl alcohol (PVA) and xanthan gum (XG) were immersed in zinc sulfate (ZnSO 4) solution to obtain ICHs with exceptional mechanical properties. The salt-out effects between PVA chains and SO 4 2− ions along with the cross-linked network of XG chains and Zn2+ ions contribute to the desirable mechanical properties of ICHs. Notably, the mechanical properties of ICHs can be adjusted by changing the concentration of ZnSO 4 solution. Consequently, the optimum fracture stress and the fracture energy can reach 3.38 MPa and 12.13 KJ m−2, respectively. Moreover, the ICHs demonstrated a favorable sensitivity (up to 2.05) when utilized as a strain sensor, exhibiting an accurate detection of human body movements across various amplitudes. [Display omitted] [ABSTRACT FROM AUTHOR]

• Thin-wall high-pressure die-cast (HPDC) aluminum alloys are subjected to FSP. • After FSP, high iron, A380 alloy requires 126% higher energy to tear, and it has 49% higher tear strength. • For premium-quality Aural-5 alloy, FSP enhances tear energy and strength by 69% and 21%, respectively. • Combined effect of microstructure refinement and porosity elimination enhanced tear resistance and toughness. In this study, we investigate the toughness and resistance to tear of thin-wall high-pressure die-cast (HPDC) aluminum alloys in two different orientations following the implementation of friction stir processing (FSP). The FSP technique was applied to two different HPDC Al-Si alloys: the recyclable-grade, high iron, A380 alloy and the premium-quality, low iron, Aural-5 alloy. Our findings reveal significant tear resistance and strength enhancements for both alloys after FSP modification. Specifically, FSPed A380 alloy requires 126% higher energy to tear, and it has 49% higher tear strength than the HPDC counterpart. Similarly, the tear energy and tear strength of the Aural-5 alloy witness enhancements of 69% and 21%, respectively. These findings emphasize the capability of FSP to improve the toughness of HPDC aluminum alloys, creating new possibilities for preventing cracks in a variety of engineering applications. [ABSTRACT FROM AUTHOR]

A convenient tape-casting method was applied to prepare high performance aromatic polyamide (PA) films based on Technora®. During the polycondensation, CaO was introduced to improve the solubility of the PA resin, and the generated halides were totally removed from the film via a simple water bath, without leaving any defects in PA films. The factors of processing temperature and immersion time had been systematically investigated, and the experimental results demonstrated that both of them had impressive impacts on aggregation state and comprehensive properties of the PA film. It was suggested that immersion in water for more than 1 min and baking below 300 °C for 10 min were the optimal conditions for the thermal, tensile, tear, and optical properties to be in the best equilibrium. The resultant PA films integrated outstanding film-forming ability and excellent general performance, especially the tensile property and tear resistance. [ABSTRACT FROM AUTHOR]

Fused Deposition Modelling (FDM) is a widely used additive manufacturing process. It utilizes a variety of homogeneous and heterogeneous materials for product development. A new manufacturing process termed as Hybrid Fused Deposition Modelling (HFDM) has been used for the manufacture of various copper metal mesh (99.99% pure)/PLA (polylactic acid or polylactide) plastic composites. These products have been subjected to standardized experimental testing for evaluating properties such as tear resistance, tensile strength, water absorption, hardness, and flexural strength. The tests have been conducted to analyse the effectiveness of the HFDM process in manufacturing stronger composites compared to commercially available PLA and copper-infused PLA. Microstructural characterization has also been carried out to analyse the bond between the plastic and metal mesh layers. The results have been promising and demonstrate the effectiveness of HFDM to produce Cu/PLA composites with superior mechanical properties compared to parent FDM-printed PLA plastic as well as copper-infused FDM-printed PLA. Multiple copper mesh layers have been placed strategically within the test specimens to study their effect on the composites made by HFDM. The experimental results show that the process is capable of manufacturing high-quality composites (Cu/PLA) with tailored properties for various engineering applications. [ABSTRACT FROM AUTHOR]

Antecedentes: los taninos son sustancias orgánicas que reaccionan con las proteínas del colágeno de las pieles de animales uniéndolas entre sí, aportando gran resistencia a la piel. Bajo esta premisa, estos metabolitos polifenólicos son una alternativa potencial para la industria de las curtiembres, siendo utilizadas en los procesos de transformación de las pieles a cueros. Objetivo: extraer y cuantificar los taninos vegetales presentes en la semilla del mango criollo (Mangifera indica) para su potencial aplicación como curtiente en la piel ovina de la raza Santa Inés (Ovis aries). Métodos: para ello, se realizó la extracción de los taninos vegetales comparando la mejor concentración disolvente etanol - agua entre 70:30 y 50:50. Se cuantificó la concentración de taninos mediante el análisis de espectrofotometría UV - VIS, método Folin Ciocalteu. Se evaluó la capacidad de curtición en la piel ovina mediante las propiedades físicas del cuero, ruptura de la flor, resistencia al desgarre, tensión y elongación. Resultados: los resultados de cuantificación de compuestos fenólicos expresados en ácido tánico permitieron observar que la mayor concentración en la almendra del mango es la solución etanol - agua 50/50 con 114,77 ppm. Los cueros ovinos curtidos por los extractos vegetales superaron las pruebas de resistencia a la tracción 12,7 MPa para la concentración de etanol - agua (50 % - 50 %) y 11,3 MPa para la concentración de etanol - agua (70 % - 30 %), esto conforme a las Normas Oficiales de la Unión Internacional de Asociaciones de Químicos del Cuero IUP (pruebas de encogimiento, ruptura de la flor, resistencia al desgarre, tensión y elongación). Conclusiones: con base en lo anterior, se estima que la almendra de mango (Mangifera indica) puede ser una alternativa de aprovechamiento para la extracción de taninos y así utilizarlos en el curtido ecológico de pieles cambiando la curtición con cromo. [ABSTRACT FROM AUTHOR]

Elastomers which are strong, tough, and resistant to tearing, are highly attractive for engineering applications such as conveyer belts, high-performance seals, tires, and soft robotics. Enhancing these properties for natural rubber materials is possible by utilizing nanoscale fillers, however the nanocomposite approach remains challenging because (a) nanofillers can impede latex molecular crosslinking, and (b) reduce the material's inherent elasticity and compliance. This study demonstrates an approach to prepare ultra-strong, tear-resistant natural rubber nanocomposites using cellulose nanofibers decorated with nanoscale lignin. The reinforcement of latex with 0.1 wt% cellulose nanofibre compatibilized with 0.5 wt% lignin resulted in a 256% improvement in tear strength, 95% in tensile strength, and 50% in toughness, while retaining the elongation at break. Such a simultaneous improvement in tensile and tear properties has not been previously achieved through the latex casting method with any other fillers, and herein it is attributed to the nanoscale reinforcement efficiency of nanofibre coupled with enhanced interfacial adhesion between nanofibers and NR latex with the introduction of nanoscale lignin. This compatibilization approach has also resulted in improved resilience in the nanocomposites, as evidenced by the cycling loading and unloading analysis. [Display omitted] • Bio-inspired compatibilisation approach for enhancing nanofibre dispersion. • A facile methodology to improve compatibility of nanocellulose in latex. • Remarkable achievement in broader property profile including tear resistance (256%). • In-depth discussion on simultaneous improvement in tear and tensile properties. • Industrially scalable for casting process and extended for dipping process. [ABSTRACT FROM AUTHOR]

In recent years, ion conductive hydrogels based on photocurable 3D printing technology have attracted wide attention in the application of wearable sensors, which greatly simplifies the manufacturing process of devices, while making devices with high sensitivity and high fidelity. However, the current ionic hydrogel network via photocuring 3D printing is mainly crosslinked by covalent bonds. Due to the lack of sufficient energy dissipation and high-functionality cross-links within the network, the gel will inevitably crack after continuous dynamic loading. Here, we designed an organic gel with excellent tear resistance, which is mainly attributed to the high-functionality cross-links constructed by nano-clay containing a large number of hydroxyl groups. Specifically, the precursor of the organic gel is mainly composed of N-methylol acrylamide (NAM), nano-clays, photoinitiator, and water-glycerol binary solvent system. After photocurable printing, lots of hydrogen bonds are formed between nano-clays and poly-NAM network, which not only provides an energy dissipation mechanism for the gel network, but also acts as a nanoscale cross-linking site to resist crack propagation during the stretching of the gel. Under the action of nano-clay, the tear resistance of the gel has been greatly improved. In addition, the sodium ions released by the nano-clay ensure the good ionic conductivity of the gel, verifying its potential as a strain sensor with high sensitivity. What's more, combining skin-like organic gels and 3D printing technology enables the manufacture of highly sensitive sensors much easier and more designable. This study not only provides a method for the preparation of high-precision ionic conductors with excellent tear resistance, but also clears the way for developing a new class of wearable devices and intelligent electronics. [Display omitted] [ABSTRACT FROM AUTHOR]

Hydrogels are considered to be ideal materials for the preparation of preoperative models and flexible wearable devices due to their softness and plasticity. However, there are still some problems in their application, such as how to achieve the construction of complex spatial structures through 3D printing and poor mechanical properties of the gel, especially poor tear resistance will greatly shorten the service life of hydrogels. In this study, with acrylamide (AM), stearyl methacrylate (SMA) and Multi-arm Crosslinking Agent (AGE-M) as the main raw materials, we provided a tear-resistance gel that can be photocurable for 3D printing. Through digital light processing (DLP)-based 3D printing, various gel-based preoperative models and devices with complex structures can be prepared. More importantly, the printed gel is endowed with excellent tear resistance by introducing the AGE-M as a nanoscale high-functionality crosslinker. In addition, the conductive substance sodium chloride is introduced to make the gel have a certain conductivity, and the organic solvent glycerol is introduced to replace part of the water to form a binary phase organic solvent, which endows the gel with excellent anti-drying and anti-freezing properties, to be suitable for more environments. Therefore, this work proposes a tear-resistance gel processed by DLP-based 3D printing technology, which can be used for the personalized manufacturing of organ models and flexible wearable devices, and is expected to be used in surgical training and artificial intelligence. [Display omitted] • The printed gel is endowed with excellent tear resistance by introducing the AGE-M as a nanoscale high-functionality crosslinker. • The double network of the gel is composed of covalent bonds and hydrophobic association. • Through light curing 3D printing, it is possible to manufacture applications in flexible wearable sensors and surgical models. [ABSTRACT FROM AUTHOR]

Abstract: Cellulose nanofibrils (CNF), once filtered and dried, have the particularity to form a highly cohesive network, nanopaper. One of the drawbacks of all CNF nanopapers is their relative brittleness and low tear resistance, measured as the force needed for crack propagation after introducing a notch. In this work, hybrid nanopapers with drastically improved tear and crumpling resistance were produced by introducing polyethylene terephthalate (PET) microfibers into the CNF suspension prior to sheet fabrication. The PET microfibers were well dispersed in the CNF suspension and subsequently evenly distributed in the formed sheets. Incorporation of 10 wt% PET fibers increased the dry tear resistance with notch by a factor of 10 while still maintaining most of the mechanical properties. This effect is attributed to the loosely bound PET fibers which limit the crack propagation by dissipating the energy. It was also possible to improve the wet tear resistance by a factor of 4. Furthermore, incorporation of PET fibers allowed for crumpling of nanopaper that previously was so brittle it shattered from the deformation. Finally, incorporation of PET fibers also improved the crumpling resistance of wet samples. The improved wet properties, together with a higher and tunable porosity, open up the possibility to use these hybrid nanopaper sheets in filtration applications. Graphical abstract: [ABSTRACT FROM AUTHOR]

The mechanical properties and tear resistance of an ecofriendly flexible packaging film, i.e., poly(lactic acid) (PLA)/poly (butylene adipate–co–terephthalate) (PBAT) film, were investigated via a blown film extrusion process. The application of PLA and PBAT in product packaging is limited due to the high brittleness, low stiffness, and incompatibility of the materials. In this study, the effects of various plasticizers, such as adipate, adipic acid, glycerol ester, and adipic acid ester, on the plasticization of PLA and fabrication of the PLA/PBAT blown film were comprehensively evaluated. It was determined that the plasticizer containing ether and ester functionalities (i.e., adipic acid ester) improved the flexibility of PLA as well as its compatibility with PBAT. It was found that the addition of the plasticizer effectively promoted chain mobility of the PLA matrix. Moreover, the interfacial adhesion between the plasticized PLA domain and PBAT matrix was enhanced. The results of the present study demonstrated that the plasticized PLA/PBAT blown film prepared utilizing a blown film extrusion process exhibited improved tear resistance, which increased from 4.63 to 8.67 N/mm in machine direction and from 13.19 to 16.16 N/mm in the transverse direction.