Mechanical Characterization of Rose Bengal and Green Light Crosslinked Collagen Scaffolds for Regenerative Medicine

Abstract Collagen is one of the most important biomaterials for tissue engineering approaches. Despite its excellent biocompatibility, it shows the non-negligible disadvantage of poor mechanical stability. Photochemical crosslinking with rose bengal and green light (RGX) is an appropriate method to improve this property. The development of collagen laminates is helpful for further adjustment of the mechanical properties as well as the controlled release of incorporated substances. In this study, we investigate the impact of crosslinking and layering of two different collagen scaffolds on the swelling behavior and mechanical behavior in micro tensile tests to obtain information on its wearing comfort (stiffness, strength and ductility). The mechanical stability of the collagen material after degradation due to cell contact is examined using thickness measurements. There is no linear increase or decrease due to layering homologous laminates. Unexpectedly, a decrease in elongation at break, Younǵs modulus and ultimate tensile strength is measured when the untreated monolayer is compared to the crosslinked one. Furthermore we can detect a connection between stability and cell proliferation. The results show that with variation in number and type of layers, collagen scaffolds with tailored mechanical properties can be produced. Such a multi-layered structure enables the release of biomolecules into inner or outer layers for biomedical applications.

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Strength Enhancement of Superduplex Stainless Steel Using Thermomechanical Processing

Metals ◽

10.3390/met11071094 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1094

Author(s):

M. A. Lakhdari ◽

F. Krajcarz ◽

J. D. Mithieux ◽

H. P. Van Landeghem ◽

M. Veron

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Thermomechanical Processing ◽

Tensile Tests ◽

Image Correlation ◽

Strength Enhancement ◽

Industrial Material ◽

Superduplex Stainless Steel ◽

The Impact ◽

Strength Improvement

The impact of microstructure evolution on mechanical properties in superduplex stainless steel UNS S32750 (EN 1.4410) was investigated. To this end, different thermomechanical treatments were carried out in order to obtain clearly distinct duplex microstructures. Optical microscopy and scanning electron microscopy, together with texture measurements, were used to characterize the morphology and the preferred orientations of ferrite and austenite in all microstructures. Additionally, the mechanical properties were assessed by tensile tests with digital image correlation. Phase morphology was not found to significantly affect the mechanical properties and neither were phase volume fractions within 13% of the 50/50 ratio. Austenite texture was the same combined Goss/Brass texture regardless of thermomechanical processing, while ferrite texture was mainly described by α-fiber orientations. Ferrite texture and average phase spacing were found to have a notable effect on mechanical properties. One of the original microstructures of superduplex stainless steel obtained here shows a strength improvement by the order of 120 MPa over the industrial material.

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Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

Sustainability ◽

10.3390/su13105494 ◽

2021 ◽

Vol 13 (10) ◽

pp. 5494

Author(s):

Lucie Kucíková ◽

Michal Šejnoha ◽

Tomáš Janda ◽

Jan Sýkora ◽

Pavel Padevět ◽

...

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Cross Section ◽

Negative Impact ◽

Tensile Tests ◽

Thermal Recovery ◽

Bending Test ◽

Small Scale ◽

Spruce Wood ◽

The Impact

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

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Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder

Materials ◽

10.3390/ma13051242 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1242

Author(s):

Olga Mysiukiewicz ◽

Paulina Kosmela ◽

Mateusz Barczewski ◽

Aleksander Hejna

Keyword(s):

Mechanical Properties ◽

Melt Flow Index ◽

Tensile Tests ◽

Mechanical Analysis ◽

Flow Index ◽

Scanning Calorimetry ◽

Metal Composites ◽

Pre Treatment ◽

The Impact ◽

Properties Of Composites

Investigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry), thermal (differential scanning calorimetry), as well as static (tensile tests, hardness, rebound resilience) and dynamic (dynamical mechanical analysis) mechanical properties of composites were investigated. The incorporation of 1 and 2 wt% of aluminum filler resulted in small enhancements of mechanical properties, while loadings of 5 and 10 wt% provided materials with a similar performance to neat HDPE. Such results were supported by the lack of disturbances in the rheological behavior of composites. The presented results indicate that a significant content of aluminum filler may be introduced into the HDPE matrix without additional pre-treatment and does not cause the deterioration of composites’ performance, which should be considered beneficial when engineering PE/metal composites.

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Impact of mineral composition and distribution on the mechanical properties of porous media

E3S Web of Conferences ◽

10.1051/e3sconf/202020502006 ◽

2020 ◽

Vol 205 ◽

pp. 02006

Author(s):

Olivia M. Brunhoeber ◽

Dinu Arakkal ◽

Rourou Ji ◽

Marta Miletić ◽

Lauren E. Beckingham

Keyword(s):

Mechanical Properties ◽

Porous Media ◽

Mineral Composition ◽

Tensile Tests ◽

Mineral Dissolution ◽

Image Correlation ◽

Geological Sequestration ◽

Thin Sections ◽

Natural Rock ◽

The Impact

Geological sequestration of CO2 in deep saline formations is a promising means of reducing atmospheric CO2 emissions. Once injected, CO2 dissolves into formation brine, lowering pH and creating conditions favorable for mineral dissolution. Cations released from dissolving minerals may create conditions favorable for secondary mineral precipitation, which can result in the long-term mineralogical trapping of injected CO2. These reactions may alter the natural rock mechanical properties, which can affect the safety and efficiency of geological sequestration. This work aims to investigate the impact of mineral composition and distribution on the mechanical properties of porous media. In this study, the mineralogy, mineral distribution, and mechanical properties of samples from Escambia County, AL, are evaluated. The mechanical properties of the rock samples are evaluated using the unconfined compression and indirect tensile tests in the combination with digital image correlation. The mineral composition and distribution are determined through the analysis of scanning electron microscopy backscattered electron and energy dispersive X-ray spectroscopy images of thin sections. These analyses showed that the mechanical properties vary with composition, which may have significant practical consequences for geological sequestration of CO2.

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Damage mechanisms and embrittlement kinetics in a β-rich Ti 17 alloy after long term aging

MATEC Web of Conferences ◽

10.1051/matecconf/202032106008 ◽

2020 ◽

Vol 321 ◽

pp. 06008

Author(s):

Layla SASAKI ◽

Gilbert HENAFF ◽

Mandana ARZAGHI ◽

Patrick VILLECHAISE ◽

Samuel HEMERY ◽

...

Keyword(s):

Mechanical Properties ◽

Detrimental Effect ◽

Damage Tolerance ◽

Tensile Tests ◽

Mechanical Resistance ◽

Damage Mechanisms ◽

Structural Parts ◽

The Impact

The Ti 17 (Ti-5Al-2Sn-2Zr-4Mo-4Cr) alloy is used in the first stages of engine compressors, at temperatures up to 450°C. However, its use in structural parts such as engine pylons is more prospective and raises the question of damage tolerance. As the engine pylon environment involves prolonged exposures to high temperatures, the impact of aging on mechanical properties has also to be taken in account. In this work, the consequences of a long-term aging (up to 10 000 h at 450°C) on the mechanical resistance of a Ti 17 alloy are examined at different scales, from macroscopic fatigue crack growth tests to in-situ tensile tests performed on micro samples in a SEM. The detrimental effect of aging on the mechanical properties of the Ti 17 alloy was then discussed in the light of damage mechanisms analysis and embrittlement kinetics.

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On the Impact of the Intermetallic Fe2Nb Laves Phase on the Mechanical Properties of Fe-6 Al-1.25 Nb-X W/ Mo Fully Ferritic Light-Weight Steels

Metals ◽

10.3390/met11111693 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1693

Author(s):

Robin Emmrich ◽

Ulrich Krupp

Keyword(s):

Mechanical Properties ◽

Room Temperature ◽

Elevated Temperatures ◽

Xrd Analysis ◽

Tensile Tests ◽

Laves Phase ◽

Particle Analysis ◽

Strength Increase ◽

Niobium Content ◽

The Impact

The present study aims at the development of precipitation hardening fully ferritic steels with increased aluminum and niobium content for application at elevated temperatures. The first and second material batch were alloyed with tungsten or molybdenum, respectively. To analyze the influence of these elements on the thermally induced precipitation of the intermetallic Fe2Nb Laves phase and thus on the mechanical properties, aging treatments with varying temperature and holding time are performed followed by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) including elemental contrast based particle analysis as well as hardness measurements and tensile tests at room temperature and at 500 °C. The incorporation of molybdenum into the Laves phase sets in at an earlier stage of aging than the incorporation of tungsten, which leads to faster growth and coarsening of the Laves phase in the molybdenum-alloyed steel. Nevertheless, both concepts show a fast and massive increase in hardness (280 HV10) due to precipitation of Laves phase during aging at 650 °C. After 4 h aging, the yield strength increase at room temperature is 100 MPa, which stays stable at operation temperatures up to 500 °C.

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Mechanical Properties of Thermoplastic Polymers for Aligner Manufacturing: In Vitro Study

Dentistry Journal ◽

10.3390/dj8020047 ◽

2020 ◽

Vol 8 (2) ◽

pp. 47 ◽

Cited By ~ 1

Author(s):

Francesco Tamburrino ◽

Vincenzo D’Antò ◽

Rosaria Bucci ◽

Giulio Alessandri-Bonetti ◽

Sandro Barone ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Yield Stress ◽

Artificial Saliva ◽

In Vitro Study ◽

Tensile Tests ◽

Operating Conditions ◽

Thermoplastic Polymers ◽

The Impact

The use of metal-free thermoplastic materials plays a key role in the orthodontic digital workflow due to the increasing demand for clear aligner treatments. Three thermoplastic polymers commonly used to fabricate clear aligners, namely Duran®, Biolon® and Zendura®, were investigated to evaluate the effect of thermoforming (T.), storage in artificial saliva (S.A.S.) and their combination on their mechanical properties. Elastic modulus and yield stress of the specimens were characterized. Each material was characterized for each condition through tensile tests (ISO527-1). The results showed that thermoforming does not lead to a significant decrease in yield stress, except for Zendura® that showed about a 30% decrease. An increase of the elastic modulus of Duran® and Zendura®, instead, was observed after thermoforming. The same increase was noticed for the yield stress of Duran®. For S.A.S. specimens, the elastic modulus generally decreases compared to supplier condition (A.S.) and simply thermoformed material. A decrease of yield stress, instead, is significant for Zendura®. The results demonstrated that the impact of the operating conditions on the mechanical properties can vary according to the specific polymer. To design reliable and effective orthodontic treatments, the materials should be selected after their mechanical properties are characterized in the simulated intraoral environment.

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Influence of Moisture-Uptake on Mechanical Properties of Polymers Used in Microelectronics

MRS Proceedings ◽

10.1557/proc-511-359 ◽

1998 ◽

Vol 511 ◽

Cited By ~ 16

Author(s):

R. Buchhold ◽

A. Nakladal ◽

G. Gerlach ◽

K. Sahre ◽

K.-J. Eichhorn ◽

...

Keyword(s):

Mechanical Properties ◽

Polymer Films ◽

Semiconductor Device ◽

Mechanical Stability ◽

Climatic Conditions ◽

Device Fabrication ◽

Film Stress ◽

Moisture Uptake ◽

Out Of Plane ◽

The Impact

ABSTRACTPolymers are currently considered as a possible alternative to silicon dioxide in the fabrication of interlevel dielectrics. To penetrate mainstream semiconductor device fabrication polymers have to meet a number of requirements regarding their long-term stability. One aspect is the mechanical stability of integrated polymer films under changing climatic conditions. In the present work, the impact of ambient moisture on the mechanical properties of thin polymer films (PI, BCB, and PFCB) was investigated. The sorption of water molecules in these materials typically causes an anisotropic volume expansion, resulting in increased mechanical film stress if the film is physically constrained by adjacent inorganic structures. Especially polyimides show both considerable moisture uptake and large changes in the mechanical film stress, while BCB and PFCB are virtually insensitive to ambient moisture. In the paper, experimental data (water uptake, in-plane swelling, out-of-plane swelling) are presented and discussed in detail.

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INFLUENCE OF MOISTURE ON MECHANICAL PROPERTIES OF CELLULOSE INSULATION PAPER

International Journal of Modern Physics B ◽

10.1142/s0217979214500519 ◽

2014 ◽

Vol 28 (07) ◽

pp. 1450051 ◽

Cited By ~ 3

Author(s):

Y. Y. WANG ◽

M. TIAN ◽

H. X. XU ◽

P. FAN

Keyword(s):

Mechanical Properties ◽

Hydrogen Bond ◽

Young’S Modulus ◽

Young's Modulus ◽

Tensile Tests ◽

Appreciable Effect ◽

Mechanical Parameters ◽

Amorphous Cellulose ◽

Hydrogen Bond Networks ◽

The Impact

This paper aims to investigate the impact of moisture on mechanical properties of insulation paper. According to the molecular modeling approach proposed by Theodorou, the amorphous cellulose models of insulation paper with different moisture contents were built up to calculate mechanical parameters and hydrogen bond networks. And relevant conclusions could be drawn through further analysis on these calculation results: water molecules can destroy hydrogen bond network between the neighboring cellulose molecules, which might be responsible for the significant decrease of Young's modulus and other mechanical parameters, while no appreciable effect of intramolecular hydrogen bonds on mechanical properties was detected. Thus tensile tests were also carried out to study the moisture influence on the Young's modulus, by which the result of the simulation was approved.

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Ex Vivo Dermis Mechanical Behavior in Relation to Decellularization Treatment Length

The Open Biomedical Engineering Journal ◽

10.2174/1874120701610010034 ◽

2016 ◽

Vol 10 (1) ◽

pp. 34-42 ◽

Cited By ~ 7

Author(s):

Mara Terzini ◽

Cristina Bignardi ◽

Carlotta Castagnoli ◽

Irene Cambieri ◽

Elisabetta M. Zanetti ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Sodium Hydroxide ◽

Structural Properties ◽

Structural Integrity ◽

Ex Vivo ◽

Tensile Tests ◽

Treatment Length ◽

Native Tissue ◽

The Impact

Background: The dermis is a commonly used source tissue for biologic scaffolds; all cellular and nuclear materials need to be removed to limit the inflammatory immune response by the host organism. The decellularization is critical because it must preserve the structural integrity of the extracellular matrix. This work has analyzed a decellularization procedure commonly followed for the dermal tissue that is a chemical treatment with sodium hydroxide. The goal of this work is to identify the optimal treatment length on the basis of structural properties. Methods: Tensile tests have been performed on the native tissue and on tissues decellularized for 1-7 weeks in sodium hydroxide. The collected data have been analyzed through Tukey-Kramer test to assess if the mechanical properties (ultimate tensile stress and elastic modulus) of decellularized tissues were significantly different from the properties of the native tissue. These tests have been performed on specimens cut along two orthogonal directions (parallel and perpendicular to Langer’s lines). Results: The decellularization treatment performed with sodium hydroxide in general weakens the tissue: both the ultimate stress and the elastic modulus get lower. The structural properties along Langer lines orientation are more strongly impacted, while the structural properties orthogonal to Langer lines can be preserved with an optimal duration of the decellularization treatment that is 5-6 weeks. Conclusion: The duration of the decellularization treatment is critical not only to reach a complete decellularization, but also to preserve the mechanical properties of the tissue; 5-6 week treatment performed with sodium hydroxide allows preserving the mechanical properties of the native tissue perpendicularly to Langer lines orientation, and minimizing the impact of the decellularization process on the mechanical properties along the Langer lines orientation.

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