High Breaking Strain Research Articles

A comparison of native vaginal and ligament surgery for cure of pelvic organ prolapse and overactive bladder.

The key messages from the Shkarupa et al. native cardinal/uterosacral ligament (CL/USL) study, was that, in premenopausal women, ligament repair alone is sufficient for cure of pelvic organ prolapse (POP) and urgency, achieving cure rates of 85.7% for POP and 81.6% for urgency at 12 months. However, in postmenopausal women, the cure rates were 20.5% for POP and 33.3% for urge at 12 months. The Lancet Prospect Trial recorded 21% for native vaginal repair at 12 months. The poor POP cure rate in the Prospect Trial, and the rapid deterioration in the post-menopausal CL/USL repair group, can be explained by known biomechanics. The vagina has little structural strength. Ligaments, with a much higher breaking strain, are the main structural support of pelvic organs. Yet, even native ligament repair reported very low cure rates at 12 months. The poor results in postmenopausal women with native ligament repair can be explained by collagen breakdown after the menopause, as collagen is the key structural component of ligaments. An important question posed in the ligament repair study was, "What happens to women cured by ligament repair after the menopause when the collagen leaches out of the ligaments?". One recommendation was that collagen creating tapes be routinely applied in prolapse surgery and OAB, at least in postmenopausal women. The recommendation for routine collagen-creating ligament repair methods, especially in older women, are supported by high 5-year surgical cure rates in 70-year-old Japanese women, 91.2% for POP, at 12 months, falling to 79.0 at 60 months, using collagen creating Tissue Fixation System (TFS) minislings.

Mono-dispersion decorated ultra-long single-walled carbon nanotube/aramid nanofiber for high-strength electromagnetic interference shielding film with Joule heating properties

High-strength, flexible, and multifunctional characteristics are highly desirable for electromagnetic interference (EMI) shielding materials to meet lightweight applications in the electric industry. Herein, we report a sustainable bioinspired double-network structural material connected by a hydrogen-bonded interface, that enables the creation of hybrid dual-networks benefiting from the mono-dispersion of aramid nanofibers (ANFs) and single-walled carbon nanotubes (SWCNTs). By directional filtration, the dual networks of the ANF/SWCNT composite films can be constructed into a laminated structure with preferential orientation during the stretching process, resulting in high fracture strength (113.45 MPa) and low breaking strain (<2%). Simultaneously, the as-prepared film delivers an adjustable electrical conductivity (131.9–798.57 S/cm), a remarkable EMI SE (43.01–75.28 dB), and high specific shielding effectiveness (SSE/t) of 1.281 × 104 dB cm2 g−1, which shows outstanding performance among the reported state-of-the-art SWCNT-based materials. More importantly, the films show excellent Joule heating performance with a fast thermal response (<15 s), a low driving voltage (0.5–5 V), and a wide temperature response range (89–445 °C). As such, the multifunctional composite films are considered as promising alternatives to a wide range of lightweight applications in electromagnetic shielding and thermal management.

Soluble-protein-aggregate-assisted improvements in heat-induced gel properties: Effect of genipin-mediated crosslinks on egg white protein

Genipin, a covalent crosslinker, has attracted significant attention from the food industry. Herein, the color, heat-induced gelling properties, and soluble aggregate character of the genipin-treated egg white were investigated to clarify the impact of soluble protein aggregates on the gel properties of egg white protein.After genipin pretreatment, the egg white protein turned dark blue and retained this color after heat-induced gelling. The genipin-pretreated egg white protein gel exhibited up to 2.9-fold and 13% higher breaking strength and strain, respectively, compared to non-treated egg white gel. The gel-breaking strength and strain correlated well with the color, before and after gelling. Gel electrophoresis, size exclusion, and anion exchange high-performance liquid chromatography revealed that a soluble protein aggregate with a negatively charged surface formed during pretreatment. The genipin-treated egg white protein formed a finely structured gel with high breaking strength and strain at all tested NaCl concentrations, indicating that the enhanced negative charge of the surface did not contribute to improving the gel properties.The soluble protein aggregates formed via covalent crosslinking are important for improving gel properties. The proposed method is a novel environmentally friendly method for enhancing the gel properties of egg white protein.

Molecular dynamics simulation of dislocation network formation and tensile properties of graphene/TiAl-layered composites

Alternating stacked graphene/TiAl (Gr/TiAl) composites exhibit excellent mechanical properties because of their high strength, high Young's modulus, and the two-dimensional atomic structure of graphene. Herein, a molecular dynamics approach was used to investigate the uniaxial tensile properties of Gr/TiAl composites after rapid solidification. The results of the simulation show that after rapid solidification, the composites were more crystallizable and were accompanied predominantly by a Shockley type dislocation network, with large periodic hexagonal superlattices (also known as the Moiré pattern) of ∼12.519 and 10.092 Å. Increasing the tensile load activates dislocation emission, which enhances the interaction between dislocations and numerous dislocations, forming a large number of entangled dislocation nodes. This increases resistance to the motion of the remaining dislocations and creating a strengthening effect. The spacing between graphene layers has a substantial effect on the tensile strength and Young's modulus of the Gr/TiAl composites. The composites with smaller layer spacing exhibited better performance than those with larger layer spacing. Because of the dislocation-blocking mechanism between Gr/TiAl interfaces, graphene blocks the propagation of dislocations and takes up most of the load, yielding composites with high Young's modulus, tensile strength, and breaking strain than pure TiAl.

Rheological, morphological and swelling properties of dysprosium-based composite hydrogel beads of alginate and chitosan: A promising material for the effective cationic and anionic dye removal

An alginate (Alg) and Alginate-chitosan (Alg-Ch) based novel hydrogel beads were fabricated by ionotropic gelation method using trivalent lanthanide dysprosium (Dy3+) ion as crosslinking agent. The chemical components, morphology and viscoelasticity of the as-prepared hydrogels were characterized by Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM) and rheology. The hydrogels beads with high content of Alginate were smooth but with increase in chitosan in the hybrid beads, significant macro-porous structure was observed by FE-SEM. The Dy-Alg beads possess higher viscoelasticity compared to Dy-Alg-Ch hybrid beads along with the higher breaking strain and structure recovery as revealed by rheology. However, the hydrogel beads of 1:1 and 2:1 Dy-Alg-Ch showed stable gel structure upto 80 °C in contrast to Dy-Alg or 1:2 Dy-Alg-Ch hydrogel beads showing stabilization effect of adding chitosan to Dy-Alg beads. The hybrid hydrogel beads (1:2 and 1:1) showed much better swelling compared to Dy-Alg hydrogel beads. The as-prepared beads with higher chitosan content showed significantly high adsorption of cationic dye Rhodamine B (RhB) whereas decrease in chitosan content favored the adsorption of anionic dye Fluorescein (Flu). The mechanism of adsorption process was evaluated by fitting adsorption data to kinetic models which reveals that adsorption of both the dyes involve chemisorption phenomena determined mainly by film and intraparticle diffusion in case of RhB and by multiple steps in case of Flu. The easy and fast fabrication, outstanding mechanical and stable properties indicated the hydrogel as a promising material for the wastewater treatment with cost- effective performance.

Shape-Programmable Liquid Metal Fibers

Conductive and stretchable fibers are the cornerstone of intelligent textiles and imperceptible electronics. Among existing fiber conductors, gallium-based liquid metals (LMs) featuring high conductivity, fluidity, and self-healing are excellent candidates for highly stretchable fibers with sensing, actuation, power generation, and interconnection functionalities. However, current LM fibers fabricated by direct injection or surface coating have a limitation in shape programmability. This hinders their applications in functional fibers with tunable electromechanical response and miniaturization. Here, we reported a simple and efficient method to create shape-programmable LM fibers using the phase transition of gallium. Gallium metal wires in the solid state can be easily shaped into a 3D helical structure, and the structure can be preserved after coating the wire with polyurethane and liquifying the metal. The 3D helical LM fiber offered enhanced stretchability with a high breaking strain of 1273% and showed invariable conductance over 283% strain. Moreover, we can reduce the fiber diameter by stretching the fiber during the solidification of polyurethane. We also demonstrated applications of the programmed fibers in self-powered strain sensing, heart rate monitoring, airflow, and humidity sensing. This work provided simple and facile ways toward functional LM fibers, which may facilitate the broad applications of LM fibers in e-skins, wearable computation, soft robots, and smart fabrics.

Mechanical and fatigue behaviour of artificial ligaments (ALs)

A flexible biologic band, ACL is the most injured and ruptured ligament in the knees of humans and animals. This research aims to produce synthetic anterior cruciate ligaments (ACLs) and compare these ligaments' mechanical and fatigue life properties with the natural ACL and commercial synthetic grafts. Artificial ligaments were designed as a core-sheath type structure. The core consisted of straight, parallel yarns and the sheath was a tubular fabric produced by weaving or braiding techniques from polyester or Vectran® yarns. The mechanical properties of the resulting artificial ligaments (AL) were tested before and after the fatigue test and compared to those of the natural ACL and commercial artificial ACLs in the market. Results showed that all ligaments had sufficient tensile strength, and they retained it after the fatigue test. If constructed sheath and core parts were from the same type of yarns, the breaking load of ligaments was higher. The breaking strain and stiffness of woven structures, particularly with Vectran cores, were better than braided ones. After the fatigue test, the breaking strain and stiffness of AL structures with a braided sheath or polyester core were improved. This finding suggests that to prevent the laxity of knee preconditioning of the ligament is necessary if the fabric structure or yarn inherently has high breaking strain and low stiffness. Overall, this study shows that a variety of suitable candidates for replacing ruptured anterior cruciate ligaments could be developed by carefully combining the fatigue-resistant yarns with leno, narrow, and braided structures.

High strength and strain alginate fibers by a novel wheel spinning technique for knitting stretchable and biocompatible wound-care materials

Alginate fibrous materials have been applied as wound dressing to enhance wound healing due to its nontoxic, biodegradable, and hemostatic nature. Conventional nonwoven fabrication tactics, however, showed weakness in inflammation, degradation stability and mechanical properties. Herein, the wet-spun alginate fibers were prepared by a novel wheel spinning technique, then knitted into wound dressing. Benefiting from optimized wet spinning parameters and the agglomeration of alginate multimers, the fibers were endowed with elevated mechanical performances and biodegradability, which allowed for the feasibility of knitting wound-care materials. Using the new wheel spinning technique, high strength alginate fibers with 173 MPa were produced with breaking strain up to 18% and toughness of 16.16 MJ*m−3. Meanwhile, alginate fibers with high breaking strain reaching 35% were produced with tensile strength of 135 MPa and toughness of 37.47 MJ*m−3. The overall mechanical performances of these alginate fibers with high breaking strain are significantly higher (up to 2 times) than those published in the literature in term of toughness. In vitro degradation evaluation revealed that this wet spun fibrous dressing had good aqueous absorbency (50%) and sustained biodegradation properties. Furthermore, the consequent cell viability study also proved that this alginate knitted fabric is biocompatible for being applied as wound dressing.

Biomimetic soy protein‐based exterior‐use films with excellent UV‐blocking performance from catechol derivative Acacia mangium tannin

AbstractPolymer plastic is the main component of current outdoor packaging film materials that are mostly derived from fossil fuels. Its poor ultraviolet (UV) barrier performance and short service life caused by aging degradation result in increased non‐renewable consumption and environmental pollution. The most effective way to solve these problems is the development of a biomass‐based and eco‐friendly packaging with excellent UV‐blocking performance. Herein, inspired by mussels, a facile strategy is reported for the preparation of a biomimetic polymeric material via the incorporation of a biomass‐derived catechol derivative Acacia mangium tannin (AMT) into a biodegradable soy protein isolate (SPI) matrix. The morphologies, mechanical, thermal properties, and UV‐blocking abilities and mechanisms of the modified films were evaluated. With the increase of the AMT content, the stress of the composite film was found to gradually increase, and the modified SPI composite film exhibited a powerful tensile strength of 7.64 MPa and a high breaking strain of 145.6%. After the introduction of AMT, the films exhibited excellent UV‐blocking performance. As both SPI and AMT are biodegradable, this work presents an innovative design strategy for fully‐biodegradable and robust polymeric materials with excellent UV‐blocking performance that have promising potential applications in packaging.

Synthesis of polymer networks by means of addition reactions of tri-amine and poly(ethylene glycol) diacrylate or diglycidyl ether compounds

Polymer networks have been synthesized by addition reactions of tri-functional amine, tris(2-aminoethyl)amine (TAEA) or trimethylolpropane tris[poly(propylene glycol)amine terminated] ether (PPGTA), and poly(ethylene glycol) diacrylate (PEGDA), or poly(ethylene glycol) diglycidyl ether (PEGDE) in dimethyl sulfoxide (DMSO) as a solvent. These reactions yielded the gels in which the polymer networks were homogeneously swollen in DMSO. An increase in the monomer concentration increased Young’s modulus and breaking stress of the gels. The gels with PPGTA showed flexible features in comparison with those with TAEA due to the flexible molecular structure of PPGTA. The gels composed of TAEA and PEGDA or PEGDE with high molecular weight tended to show lower Young’s modulus and higher breaking strain than the gels composed of those with low molecular weight due to the decrease in the cross-linking density and/or increase in flexibility of the PEG unit accompanied by the increase in the molecular weight of PEG. The gels with PPGTA showed opposite tendency, indicating entanglement of PEG unit with high molecular weight, which would play a role of physical cross-linking points in the gels. The gels prepared in N,N-dimethylformamide (DMF) were flexible in comparison with the gels prepared in DMSO due to the high miscibility of the network and DMF. The reaction systems of TAEA and PEGDA with low molecular weight in ethanol formed porous polymeric networks derived from the phase separation during the polymerization. The porous polymeric networks were unbreakable by compression and absorbed various organic solvents.

Fabrication of novel poly(lactic acid/caprolactone) bilayer membrane for GBR application

ObjectiveGuided bone regeneration (GBR) often involves the use of membranes as barriers for soft tissues. Commercially available membranes, however, do not possess an adequately low degradation rate, resulting in limited barrier function. The purpose of this study was to develop and assess the physicochemical and biological characteristics of a novel poly(l-lactic acid/caprolactone) (PLCL) bilayer membrane and determine its usefulness for GBR application. MethodsThe experimental bilayer membrane was prepared via a two-step freezing and lyophilization process with a PLCL solution. Next, the PLCL membrane was investigated regarding tensile strength, surface roughness, in vitro degradation and clinical operability. In addition, cell proliferation and differentiation were investigated on each layer of the experimental membrane. For all experiments, a commercially available poly(lactic-co-glycolic) acid membrane was used as a control. ResultsIn vitro analysis of the PLCL bilayer membrane revealed suitable mechanical strength combined with high breaking strain, which contributed to membrane operability. In addition, the PLCL bilayer membrane had enhanced stability compared to the commercial control due to its slower degradation, and was capable of supporting cell growth and osteogenic differentiation. SignificanceThe current study confirmed that the PLCL membrane possessed a high biocompatibility and slow degradation rate that contributes to prolonged barrier function and bone regeneration. Altogether, it was considered that the PLCL bilayer membrane developed in this study was applicable for GBR treatment.

Robust, stretchable and photothermal self-healing polyurethane elastomer based on furan-modified polydopamine nanoparticles

The realization of high strengthen, large ductility, and multiple-responding for self-healing composites is an urgent problem to be solved for expanding practical applications in industry. Herein, a simple stagey was proposed to prepare multiple-responding self-healing composites, which possess outstanding both tensile strengths also ductility, by utilizing furfuryl-modified polydopamine particles (F-PDAPs) as crosslinkers in maleimide-terminated polyurethane (m-PU) based on Diels-Alder reaction. Due to the excellent photo-thermal effect of F-PDAPs and the existence of DA bonds, the composites exhibited excellent healing efficiency under NIR (91.83%) and thermal (92.54%) initiation, in particular, could locally and specifically repair any crack under near-infrared light conditions. Furthermore, the tensile strength of composite materials was reached up to 34.26 MPa with a high breaking strain of 800%. Besides, the composites exhibited outstanding adhesive strength that could be healed via thermally induced. Such excellent comprehensive performance gives the composite materials an opportunity to have great potential in the fields of coatings, binders, etc.

UV-triggered self-healing polyurethane with enhanced stretchability and elasticity

Light-activated self-healing (LSH) materials have received extensive attentions recently due to their environmentally friendly repairing methods and excellent healing performance. However, the current reported LSH materials have poor mechanical strength and elasticity, which limit their applications. Herein, a novel series of coumarin-based polyurethanes with enhanced mechanical properties and elasticity have been synthesized which possessed a dramatic breaking stress of 27 MPa with a high breaking strain of 890%. Besides, the energy dissipation efficiency in continuous stretch cycles of the as-prepared polyurethanes varied negligibly, which proves the as-prepared LSHs have excellent elasticity. Meanwhile, after cutoff, the polymers exhibited excellent self-healing performance by UV irradiation for 40 min and the best healing efficiency of strain, stress and Young's modulus were 84%, 92%, 94%, respectively. The prepared self-healing polyurethanes showed great potential applications in the fields of smart materials such as self-healing coatings, electrochemical sensors and devices, electronic skin, etc.

Towards a Supertough Thermoplastic Polyisoprene Elastomer Based on a Biomimic Strategy.

Natural rubber is one of most famous self-reinforced rubbers thanks to the phenomenon of strain-induced crystallization. It is usually used in a vulcanized form to enhance the mechanical strength but this results in recycling issues. Herein a thermoplastic analogue of vulcanized natural rubber is obtained as a structural mimic. Terminally functionalized polyisoprene rubber B-4A-PIP was prepared by using tetra-analine as physical crosslinking units. The strong binding of tetra-analine groups gave B-4A-PIP a high tensile strength (15 MPa) and breaking strain of 890 %, which is much higher than those of undecorated copolymer B-OH-PIP. B-4A-PIP has a similar onset strain of crystallization and crystallization index to vulcanized natural rubber. Randomly functionalized polyisoprene R-4A-PIP showed a much lower mechanical strength and SIC properties although R-4A-PIP and B-4A-PIP possessed similar molecular weights and amounts of tetra-analine groups.

Towards a Supertough Thermoplastic Polyisoprene Elastomer Based on a Biomimic Strategy

AbstractNatural rubber is one of most famous self‐reinforced rubbers thanks to the phenomenon of strain‐induced crystallization. It is usually used in a vulcanized form to enhance the mechanical strength but this results in recycling issues. Herein a thermoplastic analogue of vulcanized natural rubber is obtained as a structural mimic. Terminally functionalized polyisoprene rubber B‐4A‐PIP was prepared by using tetra‐analine as physical crosslinking units. The strong binding of tetra‐analine groups gave B‐4A‐PIP a high tensile strength (15 MPa) and breaking strain of 890 %, which is much higher than those of undecorated copolymer B‐OH‐PIP. B‐4A‐PIP has a similar onset strain of crystallization and crystallization index to vulcanized natural rubber. Randomly functionalized polyisoprene R‐4A‐PIP showed a much lower mechanical strength and SIC properties although R‐4A‐PIP and B‐4A‐PIP possessed similar molecular weights and amounts of tetra‐analine groups.

Manufacture and physical properties of the denim fabrics using Hanji paper yarn as weft yarn

This study aims to develop the Hanji denim fabric with Hanji combination yarn or with the Hanji paper yarn and core spun yarn in a 1:1 ratio as a weft. For the weft yarn, chemical indigo and natural indigo dyestuffs were used. The study developed four kinds of Hanji paper yarns and eight kinds of Hanji denim fabrics. In addition, the study tested the properties of the developed Hanji paper yarns, Hanji denim fabrics, and existing denim fabrics. In regard to the physical properties of yarns, the Hanji paper yarn showed a lower breaking stress but a relatively high breaking strain, and it remained a stable structure with no surface fluff. The Hanji combination yarn improved the weaving ability and had a stable structure form. In the resulting physical properties of the developed Hanji denim fabrics, they had a low apparent specific gravity, stability in dimensional change in washing and drying, a higher chance of commercialization in colorfastness to washing, medium stretchability, a similar drying velocity, and a fast absorption velocity compared to the existing denim fabrics. The study suggests that the Hanji denim fabrics are the good candidate materials for summer product development, since generally the Hanji denim fabrics have cool characteristics with the excellent absorption velocity, drying velocity, and low specific gravity.

Evaluation of Structures and Morphologies of Recycled PC/PET Blends Fabricated by High-Shear Kneading Processing

Abstract We fabricated polymer blends of recycled-PC (PC) and recycled-PET (PET) using high-shear processing technology. We also assessed its structure, morphology, and physical properties. Results of DSC measurements show that Tg of PC and Tc of PET shifted to higher temperatures by kneading under high-shear conditions. Results show further that the Tm of PET shifted to a lower temperature. Moreover, compatibilization progressed. TEM observations show that the PET domain was not confirmed completely under the kneading condition of 1 000 min−1/10 s or more. Compatibilization progressed. Tensile test results show that the PET ratio of 30 wt% (1 000 min−1/10 s) has higher breaking strain than neat PC does. Chemical resistance test results obtained by good solvent of PC demonstrated that blending of PET makes PC elution difficult.

Sputtered carbon as a corrosion barrier for x-ray detector windows

Sputtered amorphous carbon thin films were explored as corrosion resistant coatings on aluminum thin films to be incorporated into x-ray detector windows. The requirements for this application include high corrosion resistance, low intrinsic stress, high strains at failure, and high x-ray transmission. Low temperature sputtering was used because of its compatibility with the rest of the window fabrication process. Corrosion resistance was tested by exposure of carbon coated and uncoated Al thin films to humidity. Substrate curvature and bulge testing measurements were used to determine intrinsic stress and ultimate strain at failure. The composition and bonding of the carbon films were further characterized by electron energy loss spectroscopy, Raman spectroscopy, and carbon, hydrogen, and nitrogen elemental analyses. Samples had low compressive stress (down to.08 GPa), a high strain at failure (3%), and a low fraction of sp3 carbon–carbon bonds (less than 5%). The high breaking strain and excellent x-ray transmission of these sputtered carbon films indicate that they will work well as corrosion barriers in this application.

Physical and mechanical properties of Tunisian women hair.

Mechanical analysis of human hair may provide the dermatologists with several markers of considerable diagnostic importance. The aim of this study was to analyse the physical and mechanical properties of Tunisian women's hair. Surface characteristics were determined with scanning electron microscopy (SEM). Mechanical properties were studied using the Miniature Tensile Tester Model 675 (MTT675), and the Fibre Dimensional Analysis Unit Model 765 (FDAS765) of Dia-Stron, UK, was used to measure the cross-sectional area. The cross-sectional area, stress at break, strain at break, elastic modulus and total work were 4643.21 ± 817 μm(2) , 201 ± 11.26 MPa, 47.3 ± 3.6%, 3.1 ± 0.16 GPa, and 9 ± 2.2 mJ, respectively. The effects of the factors 'hair curliness' and 'age' on the physical and mechanical properties were studied. The cross-sectional area and the break load are influenced by the factors 'age' and 'curl type', whereas Young's modulus shows a significant dependency only on the age. Tunisian women hair presented good mechanical properties as shown by a greater breaking stress and higher breaking strain. Both curl type and age are important factors to consider when evaluating the behaviour of hair.

Manipulation of polycarbonate urethane bulk properties via incorporated zwitterionic polynorbornene for tissue engineering applications

Elastomeric crosslinked materials based on polycarbonate urethane (PCU) and zwitterionic polynorbornene were designed by thiol–ene click-chemistry and crosslinking reaction. The zwitterionic polynorbornene poly(NSulfoZI) with functionalisable double bonds was first treated with L-cysteine via thiol–ene click-reaction and subsequently formed a crosslinked structure upon treatment with PCU in the presence of a small amount of hexamethylene-1,6-diisocyanate as a crosslinking agent. The obtained materials possessed improved tensile strength (14–20 MPa) and initial modulus (8–14 MPa). All of these materials showed high breaking strain (eb 740–900%) except the material with a high poly(NSulfoZI) content of 28% (eb 470 ± 80%). The biodegradability of these materials was enhanced compared to blank PCU, as demonstrated by testing in PBS for five weeks. Moreover, the cytocompatibility was studied by MTT assay. The adhesion and proliferation of endothelial cells (EA.hy926) over a one-week period indicated that cell growth on these designed material surfaces was enhanced. Therefore, these zwitterionic polynorbornene-modified PCU-based materials could be suitable candidates for tissue engineering applications.