scholarly journals Synthesis, Characterization and Mechanical Properties of Nanocomposites Based on Novel Carbon Nanowires and Polystyrene

2020 ◽  
Vol 10 (17) ◽  
pp. 5737
Author(s):  
Vasilis Kostas ◽  
Maria Baikousi ◽  
Nektaria-Marianthi Barkoula ◽  
Aris Giannakas ◽  
Antonios Kouloumpis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Analytical Techniques ◽  
Polymer Nanocomposite ◽  
Precipitation Method ◽  
Templating Method ◽  
Polymer Properties ◽  
Wide Range ◽  
First Time ◽  
Range Of Values ◽  
Carbon Nanowires

Carbon into polymer nanocomposite is so far a common additive for the enhancement of the polymer properties. The properties of the polymer, such as thermal, and especially its mechanical properties, are improved by the homogeneously dispersed carbon nanoparticles on the polymer matrix. In this study, carbon wires in nano dimensions are, for the very first time, synthesized via the hard templating method from the silicate matrix MCM-41, and used as nano additives of polystyrene. The carbon nanowires were chemically oxidized, and further modified by attaching octadecylamine molecules, for the development of organic functionalities onto carbon nanowires surface. The nanocomposite materials of polystyrene with the modified carbon nanowires were prepared by a solution-precipitation method at three nano additive to polymer loadings (1, 3 and 5 wt%). The as-derived nanocomposites were studied with a combination of characterization and analytical techniques. The results showed that the thermal and mechanical properties of the polystyrene nanocomposites gradually improved while increasing nano-additive loading until 3 wt%. More specifically, the 3 wt% loading sample showed the best mechanical properties, while the 5 wt% sample was difficult to achieve satisfactory dispersion of carbon nanowires and consequently has a wide range of values.

scholarly journals Effects of a Twin-Screw Extruder Equipped with a Molten Resin Reservoir on the Mechanical Properties and Microstructure of Recycled Waste Plastic Polyethylene Pellet Moldings

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1058
Author(s):  
Hikaru Okubo ◽  
Haruka Kaneyasu ◽  
Tetsuya Kimura ◽  
Patchiya Phanthong ◽  
Shigeru Yao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Value Added ◽  
Industrial Applications ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Polymer Properties ◽  
Wide Range ◽  
Twin Screw ◽  
Recycled Plastics

Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young’s modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.

scholarly journals GRANITOIDS, RARE-METAL PEGMATITES AND Ta-Nb MINERALIZATION OF SHPOLIANO-TASHLYK ORE AREA (INGUL MEGABLOCK, UKRAINIAN SHIELD)

2018 ◽  
pp. 24-29
Author(s):  
O. Hrinchenko ◽  
S. Bondarenko ◽  
T. Mironchuk
Keyword(s):  
Rare Metal ◽  
Ukrainian Shield ◽  
Wide Range ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Isomorphic Series ◽  
Single Complex ◽  
Complex Features ◽  
First Time ◽  
Range Of Values

Composition of granites, genetically associated pegmatites and superimposed metasomatites distributed within Shpoliano-Tashlyk ore area (Ingul megablock) is considered. It is established, that on the basis of similarity in their petrographic and petrochemical features granitoids of the area can be related to single complex. Features of ore mineralization are defined by both composition of granitoids (Sgranites) after which rare-metal pegmatites are formed and intensity of superimposed metasomatic alterations. Main minerals-concentrators of Ta and Nb mineralization in granitic pegmatites and metasomatites are represented by minerals of three isomorphic series – columbite-tantalite (Fe,Mn)(Nb,Ta,Ti)2O6, ilmenorutile-struverite (Ti,Nb,Ta)O2 and pyrochlore-microlite (Ca,Na)2Ta2O6(O,B,OH,F). Depending on geological setting such ore minerals as tapiolite, ixiolite, cassiterite, uraninite, nigerite, gahnite are commonly found in association with these minerals. Chemical composion of tantalo-niobates sampled from ore-bearing pegmatites and metasomatites is investigated by microprobe analysis. Most minerals of columbite-tantalite series are characterized by distinct and rhythmic internal zonality and contrasting mosaic structure which are related to considerable heterogeneities of their chemical composition. Within one aggregate mineral phases with wide range of values – from 9,80 to 71,0 % for Ta2O5 and from 10,6 to 70,1 % for Nb2O5 – are established. Among minerals ferruginous varieties which composition relates to Fe-columbite-tantalites (Nb2O5/Ta2O5 = 1–1,2; FeO/MnO = 2,5–6) prevail. Columbite-tantalites are characterised by high contents of admixture elements present (%): TiO2 – to 5,88; WO3 – to 3,70; SnO2 – to 9,20; Sc2O3 – to 5,40. Scandium ores occur as scandium-rich minerals that are mostly confined to the minerals of columbite-tantalite series found in Polohivka ore field. On the Ukrainian Shield high contents of Sc2O3 in tantalo-niobates are established for the first time. Minerals of ilmenorutile-struverite series do not quantitatively yield to minerals of columbite-tantalite series. For minerals of this series Nb2O5/Ta2O5 ratio varies in the range of 0,6-1,4. Among characteristic admixture-elements are prevailed (%): SnO2 – to 3,1, V2O5 – to 5,05; FeO – to 11,51, Cr2O3 – to 1,20. Minerals of pyrochlore-microlite series are of subordinate importance. For the first time by results of U-Pb dating of columbite-tantalites from Mostove ore manifestation (Shpoliano-Tashlyk area) the age of Ta-Nb mineralization is established to be about 1965 ± 25 million years.

scholarly journals Big Bang Bifurcations in the Tantalus Oscillator Under Biphasic Perturbations

2019 ◽  
Vol 29 (02) ◽  
pp. 1950023
Author(s):  
Humberto Arce ◽  
Araceli Torres ◽  
Augusto Cabrera ◽  
Martín Alarcón ◽  
Carlos Málaga
Keyword(s):  
Bifurcation Diagram ◽  
Limit Cycle ◽  
Excellent Agreement ◽  
Big Bang ◽  
Wide Range ◽  
Coupling Time ◽  
First Time ◽  
Hydrodynamic Oscillator ◽  
Range Of Values ◽  
Theoretical Results

The Tantalus Oscillator is a nonlinear hydrodynamic oscillator with an attractive limit cycle. In this study, we pursue the construction of a biparametric bifurcation diagram for the Tantalus Oscillator under biphasic perturbations. That is the first time that this kind of diagram is built for this kind of oscillator under biphasic perturbations. Results show that biphasic perturbations have no effect when the coupling time is chosen over a wide range of values. This modifies the bifurcation diagram obtained under monophasic perturbations. Now we have the appearance of periodic increment Big Bang Bifurcations. The theoretical results are in excellent agreement with experimental observations.

Polypropylene based carbon nanotubes composites: structure and properties

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Daniela Tabuani ◽  
Walter Granelli ◽  
Giovanni Camino ◽  
Michael Claes
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Behaviour ◽  
Polymer Nanocomposite ◽  
Structure And Properties ◽  
Polymer Properties ◽  
Wide Range ◽  
The Matrix ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Comprehensive Study

AbstractIn the field of polymer nanocomposite materials, carbon nanotubes have attracted lots of research interests in the recent past for their potentialities in improving a wide range of polymer properties. We present here a comprehensive study on polypropylene/carbon nanotube composites evaluating the morphology as well as the thermal behaviour of the prepared systems. Pristine as well as -COOH functionalised carbon nanotubes were taken into account and melt mixed at different weight fractions with PP; the crystallisation characteristics of the material were evaluated by means of DSC and XRD and the thermal behaviour was assessed through TGA analyses. The nanotubes appear to affect significantly the properties of the matrix in a way notably dependent on the functionalization and on the filler amount.

scholarly journals Variation in the material properties by nickel substitution in copper tellurate

2020 ◽  
Author(s):  
Sudarshana Dhanarath Mardolkar ◽  
A. V. Salker
Keyword(s):  
Visible Region ◽  
Photoluminescence Property ◽  
Precipitation Method ◽  
Magnetic Studies ◽  
Dielectric Parameters ◽  
Chemical Route ◽  
Wide Range ◽  
Lower Temperature ◽  
Co Precipitation ◽  
First Time

Abstract A series of pristine and nickel doped copper tellurates possessing a wide range of applications are studied here. Use of a simple wet chemical route that is co-precipitation method has been employed for the first time, which involves the formation of desired compounds at a relatively lower temperature, thus modifying their properties. All the prepared compounds are characterized and investigated by XRD, TG – DTA, XPS, SEM, TEM to examine their phase purity, thermal stability, chemical state, and microstructural properties. The electrical resistivity studies showed an insulator - semiconductor transition behavior. Magnetic studies revealed the paramagnetic nature of the material. Antiferromagnetic to paramagnetic transition was observed at T N ~ 60 K in case of Cu 2.7 Ni 0.3 TeO 6 sample. Thermoelectric studies indicated a change in conduction mechanism with temperature. Dielectric properties with respect to frequency showed an increase in dielectric parameters with increasing dopant content. Photoluminescence property has been studied and found to show emission in the visible region.

scholarly journals Folding of Tubular Waterbomb

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jiayao Ma ◽  
Huijuan Feng ◽  
Yan Chen ◽  
Degao Hou ◽  
Zhong You
Keyword(s):  
Mechanical Properties ◽  
Fine Tuning ◽  
Design Approach ◽  
Structural Deformation ◽  
Analysis And Design ◽  
The Road ◽  
Mechanical Metamaterials ◽  
Constituent Material ◽  
Wide Range ◽  
First Time

Origami has recently emerged as a promising building block of mechanical metamaterials because it offers a purely geometric design approach independent of scale and constituent material. The folding mechanics of origami-inspired metamaterials, i.e., whether the deformation involves only rotation of crease lines (rigid origami) or both crease rotation and facet distortion (nonrigid origami), is critical for fine-tuning their mechanical properties yet very difficult to determine for origami patterns with complex behaviors. Here, we characterize the folding of tubular waterbomb using a combined kinematic and structural analysis. We for the first time uncover that a waterbomb tube can undergo a mixed mode involving both rigid origami motion and nonrigid structural deformation, and the transition between them can lead to a substantial change in the stiffness. Furthermore, we derive theoretically the range of geometric parameters for the transition to occur, which paves the road to program the mechanical properties of the waterbomb pattern. We expect that such analysis and design approach will be applicable to more general origami patterns to create innovative programmable metamaterials, serving for a wide range of applications including aerospace systems, soft robotics, morphing structures, and medical devices.

scholarly journals Engineered Collagen Matrices

2020 ◽  
Vol 7 (4) ◽  
pp. 163
Author(s):  
Vaidehi A. Patil ◽  
Kristyn S. Masters
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
De Novo ◽  
Synthetic Polymers ◽  
Chemical Modifications ◽  
Collagen Matrices ◽  
Wide Range ◽  
History Of ◽  
The Creation ◽  
Range Of Values

Collagen is the most abundant protein in mammals, accounting for approximately one-third of the total protein in the human body. Thus, it is a logical choice for the creation of biomimetic environments, and there is a long history of using collagen matrices for various tissue engineering applications. However, from a biomaterial perspective, the use of collagen-only scaffolds is associated with many challenges. Namely, the mechanical properties of collagen matrices can be difficult to tune across a wide range of values, and collagen itself is not highly amenable to direct chemical modification without affecting its architecture or bioactivity. Thus, many approaches have been pursued to design scaffold environments that display critical features of collagen but enable improved tunability of physical and biological characteristics. This paper provides a brief overview of approaches that have been employed to create such engineered collagen matrices. Specifically, these approaches include blending of collagen with other natural or synthetic polymers, chemical modifications of denatured collagen, de novo creation of collagen-mimetic chains, and reductionist methods to incorporate collagen moieties into other materials. These advancements in the creation of tunable, engineered collagen matrices will continue to enable the interrogation of novel and increasingly complex biological questions.

Sir Harry Work Melville, K.C.B. 27 April 1908 – 14 June 2000

2002 ◽  
Vol 48 ◽  
pp. 289-308
Author(s):  
John C. Bevington ◽  
Brian G. Gowenlock
Keyword(s):  
Analytical Techniques ◽  
Scientific Meeting ◽  
Heterogeneous Reactions ◽  
Research Strategies ◽  
Chemical Research ◽  
Academic Administration ◽  
Personal Involvement ◽  
Polymer Properties ◽  
Wide Range ◽  
The University

Sir Harry Melville was a physical chemist with an international reputation for his studies of gas-phase and heterogeneous reactions, polymerizations and polymer properties; much of this work was characterized by the development of analytical techniques that exploited a very wide range of physical properties. His career changed direction at the age of 48 from immediate personal involvement in the direction of research to the development of national research strategies, followed later by academic administration as a university Principal. His interests in chemical research remained active throughout his long life. For J.C.B., acquaintance with Melville began during a study of phosphorus as an incendiary agent and reading some of his published papers; there was later (in 1948) appointment to the staff at the University of Birmingham and membership of the High Polymer Research Group. B.G.G. heard him lecture at a scientific meeting in 1945, met him as external PhD examiner in 1949 and joined his department at Birmingham in 1955.

scholarly journals Effect of UV-Irradiation and Ozone Exposure on Thermal and Mechanical Properties of PLA/LDPE Films

2022 ◽  
Author(s):  
M. Podzorova
Keyword(s):  
Mechanical Properties ◽  
Ozone Exposure ◽  
Degree Of Crystallinity ◽  
Thermal And Mechanical Properties ◽  
Strength Parameters ◽  
Thermophysical Characteristics ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
The Degree Of Crystallinity ◽  
Range Of Values

Abstract. The mechanical properties of polymer composites based on polylactide vary significantly over a wide range of values. It has been established that photodegradation of low-density polyethylene – polylactide blends occurs both in the amorphous and in the crystalline phase of the PLA matrix, which leads to deterioration of the mechanical properties of the studied mixtures. Ozonolysis affects the strength parameters of polylactide-polyethylene samples as well as photodegradation. By the differential scanning calorimetry it is determined that the melting point of polylactide decreases by 2-4 °C, the glass transition temperature - by 1-3 °C, while the degree of crystallinity increases by 3-6%. In the process of ozonolysis, the thermophysical characteristics of PLA/LDPE have changed.

scholarly journals Steel with control austenitic transformation during operation

2021 ◽  
Vol 98 (2) ◽  
pp. 47-53
Author(s):  
O. M. Sydorchuk ◽  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Service Life ◽  
Industrial Test ◽  
Tempering Temperature ◽  
Austenitic Transformation ◽  
Wide Range ◽  
Copper Nickel Alloy ◽  
Treatment Structure ◽  
First Time

The intermediate class of steels, which at room temperature belong to the ferritic state, and at operating temperature pass into the austenitic region, are called steels with control of austenitic transformation during operation. The possibility of increasing the service life of such intermediate steels at high temperatures (above the critical point A3) is shown. For the first time, the cast structure and phase-structural state of steel (grade 4Kh3N5М3F) obtained by electroslag remelting were studied. An improved composition of steel (4Kh4N5М3F) for the production of stamping tools for hot pressing of copper, copper and aluminum alloys is proposed. When setting the critical points (A1 and A3) of the investigated steel, which was confirmed by the results of high-temperature X-ray phase analysis, it was possible to optimize the heat treatment (annealing) of steel 4Kh3N5M3F and 4Kh4N5M4F2 in cast and forged condition, which facilitated processing tool. The results of researches on optimization of modes of heat treatment (hardening, tempering) of steel are given. The mechanical properties (strength, toughness, heat resistance) of steel in cast and forged state depending on the tempering and tempering temperature are determined. The tempering brittleness of the experimental steel is determined. An experimental-industrial test of a stamping tool (die dies, extruder parts) made of the investigated steel was carried out. The possibility of using stamped steel with adjustable austenitic transformation for a wide range of operating temperatures of hot deformation of aluminum alloy AK7h (450-500 ºC), copper M1 (600-630 ºC) and copper-nickel alloy MNZh 5-1 (900-950 ºC) with increased service life in comparison with steels of ferrite class 4Kh5МF1S and 3Kh3М3F. Keywords: die steel, composition, thermal treatment, structure, mechanical properties.

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