scholarly journals Graphene-based polymeric nano-composites: an introspection into functionalization, processing techniques and biomedical applications

2019 ◽  
Vol 9 (3) ◽  
pp. 3926-3933 ◽  
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Scientific Community ◽  
Polymeric Materials ◽  
Biomedical Domain ◽  
Polymeric Nanocomposites ◽  
Polymeric Matrices ◽  
Functional Capabilities ◽  
Superior Mechanical Properties ◽  
Processing Techniques

Although, there have been numerous efforts in synthesis of polymers, their mechanical properties have limited their applications. Graphene has been investigated for excellent properties such as superior mechanical properties, high thermal conductivity that has attracted the attention of scientific community to employ graphene as a filler material in polymeric matrices to form composites with multi-functional capabilities. The excellent properties possessed by Graphene has motivated users to fabricate flexible nanocomposites that can be used for applications requiring superior mechanical, chemical and thermal performances. Characteristics of both the components if explored synergistically through proper structural and interfacial organization. The investigation in this direction has resulted into combination of graphene with variety of polymeric materials and hence the development of different graphene-based nanocomposites. The present work reviews the application of graphene-based nanocomposites in the biomedical domain. With this objective, the polymeric matrices suitable for biomedical applications as well as the techniques of producing graphene polymeric nanocomposites have been discussed. Finally the application particularly in biosensing, wound healing and drug delivery system has been discussed.

scholarly journals Joint Effect of Steel Addition and Press-and-Sinter on the Properties of Low-Cost PM Ti Alloys

2018 ◽  
Vol 770 ◽  
pp. 248-254
Author(s):  
Leandro Bolzoni ◽  
Elisa Maria Ruiz-Navas ◽  
Elena Gordo
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Biomedical Applications ◽  
Low Cost ◽  
Physical And Mechanical Properties ◽  
Steel Powder ◽  
Joint Effect ◽  
Ti Alloys ◽  
Commercial Steel ◽  
Processing Techniques

Cheap alloying elements and creative processing techniques are a way forward to open up more industrial opportunities for Ti in sectors where it is not extensively applied yet, rather than in aerospace and biomedical applications. This study focuses on understanding the joint effect of using a commercial steel powder to add Fe to pure Ti and its processing by press-and-sinter on the behaviour of low-cost PM Ti alloys. It is found that the calibrated addition of steel permits to develop new low-cost Fe-bearing Ti alloys that can satisfactorily be produced using the blending elemental PM approach. Densification of the samples and homogenization of the chemical composition are enhanced by the high diffusivity of Fe. The low-cost α+β alloys reach comparable physical and mechanical properties to those of wrought-equivalent PM Ti alloys, such as Ti-6Al-4V, and are therefore promising candidates for load-bearing lightweight products.

Silicone/Carbon Nanotube Sheet Biofidelic Piezoresistive Sandwich Composites

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Nengda Jiang ◽  
Sirish Namilae ◽  
Vinu Unnikrishnan
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Polymeric Materials ◽  
Analytical Models ◽  
Sandwich Composite ◽  
Sandwich Composites ◽  
Human Brain Tissue ◽  
Electrically Conductive ◽  
The Core ◽  
Electromechanical Performance

Abstract Silicone-based biofidelic surrogates are used in many biomedical applications. Apart from mimicking the mechanical behavior of bodily tissues, there is an increasing requirement for these materials to be electrically conductive and piezoresistive to facilitate direct instrumentation. Carbon nanotubes (CNTs) have been extensively investigated as fillers to impart electrical conductivity and piezoresistivity to polymeric materials including silicone. In this paper, we fabricate, test, and characterize a two-part silicone/CNT sheet sandwich composites that exhibit conductivity, piezoresistivity, and biofidelic with mechanical properties corresponding to that of the white matter of human brain tissue. The electromechanical performance of the sandwich composite improves in subsequent loading after the core fracture during initial loading. Analytical models developed for discontinuous core sandwich structures are used to analyze and explain the experimental results. The results indicate the potential for using this discontinuous core biofidelic-piezoresistive sandwich nanocomposite for biomedical applications without deploying external deformation sensors.

scholarly journals Effect of Selected Injection Conditions on the Mechanical Properties and Structure of HDPE

2018 ◽  
Vol 26 (5(131)) ◽  
pp. 93-98
Author(s):  
Katarzyna Mordal ◽  
Karol Dobrakowski ◽  
Dariusz Kwiatkowski
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Polymeric Materials ◽  
Injection Velocity ◽  
Scanning Calorimetry ◽  
Melt Flow Rate ◽  
Variable Parameters ◽  
Injection Process ◽  
Hardness Tests ◽  
Research Plan

This paper is devoted to research of high-density polyethylene (HDPE), which belongs to one of three main biomaterial groups, i.e. polymeric materials. Hence, due to its unique properties, it still plays an important role in biomedical applications – especially in the production of medical equipment, implants and parts of prostheses. This publication deals with the effect of selected conditions of processing which involved injection moulding on the mechanical properties and structure of HDPE mouldings. Samples for tests were produced on a Krauss  Maffei injection moulder on the basis of a research plan prepared using the STATISTICA program. According to this schedule, the following variable parameters of the injection process were selected: injection temperature Tw [C], mould temperature Tf [C] and injection velocity vw [mm/s]. In addition, a part of the moldings was subjected to a few processings. Then the samples obtained were subjected to different tests: tensile, impact and hardness tests, Differential Scanning Calorimetry (DSC) and the melt flow rate (MFR) test in order to determine the influence of selected injection conditions and the multiplicity of processing on the mechanical, rheological and structural properties of HDPE.

scholarly journals Mechanical Properties of Sandwich Composites Reinforced by Nanoclays: An Overview

2020 ◽  
Vol 10 (7) ◽  
pp. 2637
Author(s):  
João Parente ◽  
Paulo N. B. Reis ◽  
M. Neto ◽  
A. M. Amaro
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Exchange Capacity ◽  
Design Criteria ◽  
Sandwich Composites ◽  
Polymeric Nanocomposites ◽  
Ion Exchange Capacity ◽  
Acoustic Damping ◽  
Superior Mechanical Properties ◽  
Systematic Understanding

Structural sandwich composites have been widely used in many engineering applications, and this trend continues due to their superior mechanical properties, thermal insulation and acoustic damping. However, to further improve their mechanical properties, literature reports significant benefits obtained with nano-reinforcements. In this context, nanoclays are the most popular nano-reinforcements for polymeric nanocomposites, due to their relatively high ion exchange capacity, high aspect ratio and economic advantages. In order to stablish a systematic understanding for design criteria, this work intends to summarize all studies present in the open literature about this topic. It was possible to conclude that using nanoclays improves the mechanical properties of structural sandwich composites, especially in terms of impact strength. Nevertheless, the benefits obtained regarding fatigue performance are not adequately reported in the literature, revealing the need to develop these studies.

scholarly journals The Effect of Halloysite Addition on the Material Properties of Chitosan–Halloysite Hydrogel Composites

Gels ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 40 ◽  
Author(s):  
Luo ◽  
Mills
Keyword(s):  
Mechanical Properties ◽  
Drug Release ◽  
Biomedical Applications ◽  
Polymeric Materials ◽  
Halloysite Nanotubes ◽  
Sustained Drug Release ◽  
Nanocomposite Hydrogels ◽  
Naturally Occurring ◽  
Hydrogel Composites ◽  
Chitosan Hydrogels

Chitosan-based hydrogels are being widely used in biomedical applications due to their eco-friendly, biodegradable, and biocompatible properties, and their ability to mimic the extracellular matrix of many tissues. However, the application of chitosan hydrogels has been limited due to their inherent mechanical weakness. Halloysite nanotubes (HNTs) are naturally occurring aluminosilicate clay minerals and are widely used as a bulk filler to improve the performance characteristics of many polymeric materials. HNTs have also been shown to be a viable nanocontainer able to provide the sustained release of antibiotics, chemicals, and growth factors. This study’s objective was to develop a stable drug delivery chitosan/HNT nanocomposite hydrogel that is biocompatible, biodegradable, and provides sustained drug release. In this study, chitosan/HNTs hydrogels containing undoped or gentamicin-doped HNTs were combined in different wt./wt. ratios and cross-linked with tripolyphosphate. The effects of chitosan and HNTs concentration and combination ratios on the hydrogel surface morphology, degradability, and mechanical properties, as well as its drug release capability, were analyzed. The results clearly showed that the addition of HNTs improved chitosan mechanical properties, but only within a narrow range. The nanocomposite hydrogels provided a sustained pattern of drug release and inhibited bacterial growth, and the live/dead assay showed excellent cytocompatibility.

scholarly journals Overview on the Antimicrobial Activity and Biocompatibility of Sputtered Carbon-Based Coatings

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1428
Author(s):  
Isabel Carvalho ◽  
Lisa Rodrigues ◽  
Maria José Lima ◽  
Sandra Carvalho ◽  
Sandra M. A. Cruz
Keyword(s):  
Mechanical Properties ◽  
Medical Devices ◽  
Biofilm Formation ◽  
Biomedical Applications ◽  
Scientific Community ◽  
Chemical Elements ◽  
Water Remediation ◽  
Hazardous Chemical ◽  
Real Risk ◽  
Carbon Based

Due to their outstanding properties, carbon-based structures have received much attention from the scientific community. Their applications are diverse and include use in coatings on self-lubricating systems for anti-wear situations, thin films deposited on prosthetic elements, catalysis structures, or water remediation devices. From these applications, the ones that require the most careful testing and improvement are biomedical applications. The biocompatibility and antibacterial issues of medical devices remain a concern, as several prostheses still fail after several years of implantation and biofilm formation remains a real risk to the success of a device. Sputtered deposition prevents the introduction of hazardous chemical elements during the preparation of coatings, and this technique is environmentally friendly. In addition, the mechanical properties of C-based coatings are remarkable. In this paper, the latest advances in sputtering methods and biocompatibility and antibacterial action for diamond-based carbon (DLC)-based coatings are reviewed and the greater outlook is then discussed.

scholarly journals Surface Modification of Cellulose Nanocrystals with Lactone Monomers via Plasma-Induced Polymerization and Their Application in ABS Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2699
Author(s):  
Ramón Díaz de León ◽  
Ediberto Guzmán ◽  
Ricardo López González ◽  
Alejandro Díaz Elizondo ◽  
Ilse Magaña ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Yield Stress ◽  
Cellulose Nanocrystals ◽  
Polymeric Materials ◽  
Environmental Problems ◽  
Plasma Power ◽  
Polymeric Matrices ◽  
Promising Application ◽  
Modified Cellulose

The growing concern for environmental problems has motivated the use of materials obtained from bio-based resources such as cellulose nanocrystals which have a promising application acting as fillers or reinforcements of polymeric materials. In this context, in this article, plasma-induced polymerization is proposed as a strategy to modify nanocrystals at different plasma power intensities using ε-caprolactone and δ-decalactone to improve their compatibility with polymeric matrices. The characterization was carried out using techniques such as FTIR, TGA, XRD, XPS, and AFM, with which a successful functionalization was demonstrated without altering the inherent properties of the nanocrystals. The preparation of ABS nanocomposites was carried out with the modified nanoparticles and the evaluation of the mechanical properties indicates an increase in Young’s modulus and yield stress under certain concentrations of modified cellulose nanocrystals.

Crystallization of MgO • Al2 • SiO2 • ZrO2 glasses

1986 ◽  
Vol 44 ◽  
pp. 440-441
Author(s):  
M. A. McCoy
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Powder Processing ◽  
Glass Composition ◽  
Ceramic Powder ◽  
Transformation Toughening ◽  
Ceramic Powder Processing ◽  
Processing Techniques ◽  
Ceramic Matrices

Transformation toughening by ZrO2 inclusions in various ceramic matrices has led to improved mechanical properties in these materials. Although the processing of these materials usually involves standard ceramic powder processing techniques, an alternate method of producing ZrO2 particles involves the devtrification of a ZrO2-containing glass. In this study the effects of glass composition (ZrO2 concentration) and heat treatment on the morphology of the crystallization products in a MgO•Al2•SiO2•ZrO2 glass was investigated.

Metallic Nanoneedles Arrays for TEM Sample Preparation “Lift-Out”

2012 ◽  
Author(s):  
Romaneh Jalilian ◽  
David Mudd ◽  
Neil Torrez ◽  
Jose Rivera ◽  
Mehdi M. Yazdanpanah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Sample Preparation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Beam System ◽  
Transmission Electron ◽  
Nanoneedle Array ◽  
Superior Mechanical Properties ◽  
And Performance

Abstract The sample preparation for transmission electron microscope can be done using a method known as "lift-out". This paper demonstrates a method of using a silver-gallium nanoneedle array for a quicker sharpening process of tungsten probes with better sample viewing, covering the fabrication steps and performance of needle-tipped probes for lift-out process. First, an array of high aspect ratio silver-gallium nanoneedles was fabricated and coated to improve their conductivity and strength. Then, the nanoneedles were welded to a regular tungsten probe in the focused ion beam system at the desired angle, and used as a sharp probe for lift-out. The paper demonstrates the superior mechanical properties of crystalline silver-gallium metallic nanoneedles. Finally, a weldless lift-out process is described whereby a nano-fork gripper was fabricated by attaching two nanoneedles to a tungsten probe.

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