scholarly journals Transient Confinement of the Quaternary Tetramethylammonium Tetrafluoroborate Salt in Nylon 6,6 Fibres: Structural Developments for High Performance Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2938
Author(s):  
Ahmed Dawelbeit ◽  
Muhuo Yu
Keyword(s):  
Phase Transitions ◽  
High Performance ◽  
Melt Spinning ◽  
Structural Phase ◽  
Tensile Modulus ◽  
High Strength ◽  
Strength Properties ◽  
Nylon 6,6 ◽  
Spinning Process ◽  
Hot Drawing

A temporary confinement of the quaternary tetramethylammonium tetrafluoroborate (TMA BF4) salt among polyamide molecules has been used for the preparation of aliphatic polyamide nylon 6,6 fibres with high-modulus and high-strength properties. In this method, the suppression or the weakening of the hydrogen bonds between the nylon 6,6 segments has been applied during the conventional low-speed melt spinning process. Thereafter, after the complete hot-drawing stage, the quaternary ammonium salt is fully extracted from the drawn 3 wt.% salt-confined fibres and the nascent fibres are, subsequently, thermally stabilized. The structural developments that are acquired in the confined-nylon 6,6 fibres are ascribed to the developments of the overall fibres’ properties due to the confinement process. Surprisingly, unlike the neat nylon 6,6 fibres, the X-ray diffraction (XRD) patterns of the as-spun salt-confined fibres have shown diminishing of the (110)/(010) diffraction plane that obtained pseudohexagonal-like β’ structural phase. Moreover, the β’ pseudohexagonal-like to α triclinic phase transitions took-place due to the hot-drawing stage (draw-induced phase transitions). Interestingly, the hot-drawing of the as-spun salt-confined nylon 6,6 fibres achieved the same maximum draw ratio of 5.5 at all of the drawing temperatures of 120, 140 and 160 °C. The developments that happened produced the improved values of 43.32 cN/dtex for the tensile-modulus and 6.99 cN/dtex for the tensile-strength of the reverted fibres. The influences of the TMA BF4 salt on the structural developments of the crystal orientations, on the morphological structures and on the improvements of the tensile properties of the nylon 6,6 fibres have been intensively studied.

scholarly journals The Production of Material with Ultrafine Grain Structure in Al-Zn Alloy in the Process of Rapid Solidification

2014 ◽  
Vol 14 (2) ◽  
pp. 57-62
Author(s):  
M. Szymaneka ◽  
B. Augustyn ◽  
D. Kapinos ◽  
S. Boczkal ◽  
J. Nowak
Keyword(s):  
Rapid Solidification ◽  
Melt Spinning ◽  
Hot Extrusion ◽  
High Strength ◽  
Strength Properties ◽  
Grain Structure ◽  
Ultrafine Grain ◽  
Plastic Working ◽  
Metal Treatment ◽  
Ultrafine Grain Structure

Abstract In the aluminium alloy family, Al-Zn materials with non-standard chemical composition containing Mg and Cu are a new group of alloys, mainly owing to their high strength properties. Proper choice of alloying elements, and of the method of molten metal treatment and casting enable further shaping of the properties. One of the modern methods to produce materials with submicron structure is a method of Rapid Solidification. The ribbon cast in a melt spinning device is an intermediate product for further plastic working. Using the technique of Rapid Solidification it is not possible to directly produce a solid structural material of the required shape and length. Therefore, the ribbon of an ultrafine grain or nanometric structure must be subjected to the operations of fragmentation, compaction, consolidation and hot extrusion. In this article the authors focussed their attention on the technological aspect of the above mentioned process and described successive stages of the fabrication of an AlZn9Mg2.5Cu1.8 alloy of ultrafine grain structure designated for further plastic working, which enables making extruded rods or elements shaped by the die forging technology. Studies described in the article were performed under variable parameters determined experimentally in the course of the alloy manufacturing process, including casting by RS and subsequent fragmentation.

Study on the Compressive Strength and Mixing of Ultra-High Performance Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 825-828
Author(s):  
Su Li Feng ◽  
Peng Zhao
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Properties ◽  
Test Method ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Ultra High Performance Concrete ◽  
Mixture Ratio

The test in order to obtain liquidity, higher intensity ultra-high performance concrete(UHPC), in the course of preparation, high intensity quartz sand to replace the ordinary sand,reasonable mixture ratio control low water-cement ratio,the incorporation of part of the test piece ofsteel fibers, produced eight specimens . In the ordinary molding and the standard conservation 28d thecase, the ultra-high-performance concrete compressive strength of more than 170MPa.Thepreparation of the test method and test results will provide the basis for further study of the law of themechanical properties of ultra high strength properties of concrete.

scholarly journals The Effect of External Magnetic Field on Microstructure and Magnetic Properties of Melt-Spun Nd-Fe-B/Fe-Co Nanocomposite Ribbons

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xuan Truong Nguyen ◽  
Hong Ky Vu ◽  
Hung Manh Do ◽  
Van Khanh Nguyen ◽  
Van Vuong Nguyen
Keyword(s):  
Magnetic Field ◽  
Grain Size ◽  
High Performance ◽  
Melt Spinning ◽  
Nominal Composition ◽  
Energy Product ◽  
Melt Spun ◽  
Spinning Process ◽  
Reduction Effect ◽  
Microstructure And Magnetic Properties

The ribbons Nd2Fe14B/Fe-Co were prepared with the nominal composition Nd16Fe76B8/40% wt. Fe65Co35by the conventional and the developed magnetic field-assisted melt-spinning (MFMS) techniques. Both ribbons are nanocomposites with the smooth single-phase-like magnetization loops. The 0.32 T magnetic field perpendicular to the wheel surface and assisting the melt-spinning process reduces the grain size inside the ribbon, increases the texture of the ribbon, improves the exchange coupling, and, in sequence, increases the energy product(BH)maxof the isotropic powdered samples of MFMS ribbon in ~9% by comparison with that of the ribbon melt-spun conventionally. The grain size reduction effect caused by the assisted magnetic field has also been described quantitatively. The MFMS technique seems to be promising for producing high-performance nanocomposite ribbons.

Reliable Sn–Ag–Cu lead-free melt-spun material required for high-performance applications

2019 ◽  
Vol 234 (11-12) ◽  
pp. 757-767 ◽  
Author(s):  
Mohammed Mundher Jubair ◽  
Mohammed S. Gumaan ◽  
Rizk Mostafa Shalaby
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Electrical Resistivity ◽  
High Performance ◽  
Melt Spinning ◽  
High Strength ◽  
Thermal Environments ◽  
Aerospace Applications ◽  
Melt Spun ◽  
Melt Spinning Technique

AbstractThis study investigates the structural, mechanical, thermal and electrical properties of B-1 JINHU, EDSYN SAC5250, and S.S.M-1 commercial materials, which have been manufactured at China, Malaysia, and Germany, respectively. The commercial materials have been compared with the measurements of Sn–Ag–Cu (SAC) melt-spun materials that are only indicative of what can be expected for the solder application, where the solder will have quite different properties from the melt-spun materials due to the effects of melt-spinning technique. Adding Cu to the eutectic Sn–Ag melt-spun material with 0.3 wt.% significantly improves its electrical and mechanical properties to serve efficiently under high strain rate applications. The formed Cu3Sn Intermetallic compound (IMC) offers potential benefits, like high strength, good plasticity, consequently, high performance through a lack of dislocations and microvoids. The results showed that adding 0.3 wt.% of Cu has improved the creep resistance and delayed the fracture point, comparing with other additions and commercial solders. The tensile results showed some improvements in 39.3% tensile strength (25.419 MPa), 376% toughness (7737.220 J/m3), 254% electrical resistivity (1.849 × 10−7 Ω · m) and 255% thermal conductivity (39.911 w · m−1 · k−1) when compared with the tensile strength (18.24 MPa), toughness (1625.340 J/m3), electrical resistivity (6.56 × 10−7 Ω · m) and thermal conductivity (11.250 w · m−1 · k−1) of EDSYN SAC5250 material. On the other hand, the Sn93.5–Ag3.5–Cu3 melt-spun solder works well under the harsh thermal environments such as the circuits located under the automobiles’ hood and aerospace applications. Thus, it can be concluded that the melt-spinning technique can produce SAC melt-spun materials that can outperform the B-1 JINHU, EDSYN SAC5250 and S.S.M-1 materials mechanically, thermally and electrically.

Theory and Simulation of Fiber Texture Formation and Rheology of Carbonaceous Mesophase Fibers

2001 ◽  
Vol 709 ◽  
Author(s):  
A. D. Rey
Keyword(s):  
Liquid Crystals ◽  
High Performance ◽  
Melt Spinning ◽  
Elongational Flow ◽  
Fiber Texture ◽  
Texture Formation ◽  
Cross Sectional ◽  
Wide Range ◽  
Spinning Process ◽  
Sectional Shape

ABSTRACTCarbonaceous mesophases are discotic nematic liquid crystals that are spun into high performance carbon fibers using the melt spinning process. The spinning process produces a wide range of different fiber textures and cross-sectional shapes. Circular planar polar (PP), circular planar radial (PR) textures, ribbon planar radial (RPR), and ribbon planar line (RPL) textures are ubiquitous ones. This paper presents, solves, and validates a model of mesophase fiber texture formation based on the classical Landau-de Gennes theory of liquid crystals, adapted here to carbonaceous mesophases. The effects of fiber cross-sectional shape and elongational flow on texture formation are characterized. Emphasis is on qualitative model validation using existing experimental data [1, 2]. The results provide additional knowledge on how to optimize and control mesophase fiber textures.

scholarly journals Microstructure Evolution and Mechanical Properties of Melt Spun Skutterudite-based Thermoelectric Materials

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 984 ◽  
Author(s):  
Huiyuan Geng ◽  
Jialun Zhang ◽  
Tianhong He ◽  
Lixia Zhang ◽  
Jicai Feng
Keyword(s):  
Mechanical Properties ◽  
Spinodal Decomposition ◽  
Microstructure Evolution ◽  
Thermoelectric Materials ◽  
High Performance ◽  
Melt Spinning ◽  
Bending Strength ◽  
Annealed Sample ◽  
Submicron Scale ◽  
Spinning Process

The rapid solidification of melt spinning has been widely used in the fabrication of high-performance skutterudite thermoelectric materials. However, the microstructure formation mechanism of the spun ribbon and its effects on the mechanical properties are still unclear. Here, we report the microstructure evolution and mechanical properties of La–Fe–Co–Sb skutterudite alloys fabricated by both long-term annealing and melt-spinning, followed by sintering approaches. It was found that the skutterudite phase nucleated directly from the under-cooled melt and grew into submicron dendrites during the melt-spinning process. Upon heating, the spun ribbons started to form nanoscale La-rich and La-poor skutterudite phases through spinodal decomposition at temperatures as low as 473 K. The coexistence of the micron-scale grain size, the submicron-scale dendrite segregation and the nanoscale spinodal decomposition leads to high thermoelectric performance and mechanical strength. The maximum three-point bending strength of the melt spinning sample was about 195 MPa, which was 70% higher than that of the annealed sample.

Twist-film gel spinning of large-diameter high-performance ultra-high molecular weight polyethylene monofilaments

2016 ◽  
Vol 87 (19) ◽  
pp. 2323-2336 ◽  
Author(s):  
Xudong Fang ◽  
Jing Shi ◽  
Tom Wyatt ◽  
Donggang Yao
Keyword(s):  
Molecular Weight ◽  
Solvent Extraction ◽  
High Molecular Weight ◽  
High Performance ◽  
Large Diameter ◽  
High Strength ◽  
Gel Spinning ◽  
Solvent Removal ◽  
Spinning Process ◽  
Ultra High Molecular Weight

A twist-film gel spinning process was developed for large-diameter high-performance ultra-high molecular weight polyethylene (UHMWPE) monofilaments. By using polybutene as a spin-solvent, film twisting was demonstrated to be an effective method for solvent removal; approximately 70% of solvent contained in the gel film can be removed simply by film twisting. This mechanical solvent removal process also makes conventional solvent extraction proceed significantly faster. Besides improved solvent extraction efficiency, large-diameter high-strength UHMWPE monofilaments (with diameters of about 80 µm and strength exceeding 3.2 GPa) can be produced with this process, which is difficult to achieve using conventional processes. The capability of making large-diameter high-strength monofilaments may allow new products of UHMWPE to be developed in a number of high-performance applications.

scholarly journals Theory and Simulation of Texture Formation in Mesophase Carbon Fibers

2001 ◽  
Vol 702 ◽  
Author(s):  
J. Yan ◽  
A. D. Rey
Keyword(s):  
Carbon Fibers ◽  
High Performance ◽  
Melt Spinning ◽  
Elastic Anisotropy ◽  
Defect Migration ◽  
Geometric Factors ◽  
Spinning Process ◽  
Defect Nucleation ◽  
Mesoscopic Theory ◽  
Selection Of

ABSTRACTCarbonaceous mesophases are spun into high performance carbon fibers using the melt spinning process. The spinning process produces a range of fiber textures whose origins are not well understood. Planar polar (PP) and planar radial (PR) textures are two ubiquitous ones. A model that describes the formation process of the PP texture based on the Landau-de Gennes mesoscopic theory for discotic liquid crystals, including defect nucleation, defect migration, and overall texture geometry, is presented, solved, and validated. The computed PP and PR textures phase diagram, given in terms of temperature and fiber radius, is presented to establish the processing conditions and geometric factors that lead to the selection of these textures. The influence of elastic anisotropy to the textures formation and structure is also characterized.

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