Study of Melt Spinning Processing Conditions for a Polyacrylonitrile Copolymer with a Water/Ethanol Mixture as a Plasticizer

2019 ◽  
Vol 34 (5) ◽  
pp. 557-563
Author(s):  
J. Yu ◽  
D. G. Baird
Keyword(s):  
Melt Spinning ◽  
Processing Conditions ◽  
Ethanol Mixture ◽  
Polyacrylonitrile Copolymer

scholarly journals Fabrication of piezoelectric poly(l-lactic acid)/BaTiO3 fibre by the melt-spinning process

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hyun Ju Oh ◽  
Do-Kun Kim ◽  
Young Chan Choi ◽  
Seung-Ju Lim ◽  
Jae Bum Jeong ◽  
...  
Keyword(s):  
Phase Transition ◽  
Lactic Acid ◽  
Crystalline Phase ◽  
Melt Spinning ◽  
Piezoelectric Properties ◽  
Polymeric Materials ◽  
Processing Conditions ◽  
Post Processing ◽  
Scanning Calorimetry ◽  
Spinning Process

Abstract Poly(l-lactic acid) (PLLA) based piezoelectric polymers are gradually becoming the substitute for the conventional piezoelectric ceramic and polymeric materials due to their low cost and biodegradable, non-toxic, piezoelectric and non-pyroelectric nature. To improve the piezoelectric properties of melt-spun poly(l-lactic acid) (PLLA)/BaTiO3, we optimized the post-processing conditions to increase the proportion of the β crystalline phase. The α → β phase transition behaviour was determined by two-dimensional wide-angle x-ray diffraction and differential scanning calorimetry. The piezoelectric properties of PLLA/BaTiO3 fibres were characterised in their yarn and textile form through a tapping method. From these results, we confirmed that the crystalline phase transition of PLLA/BaTiO3 fibres was significantly enhanced under the optimised post-processing conditions at a draw ratio of 3 and temperature of 120 °C during the melt-spinning process. The results indicated that PLLA/BaTiO3 fibres could be a one of the material for organic-based piezoelectric sensors for application in textile-based wearable piezoelectric devices.

Dispersoid Modification of Ti3Al-Nb Alloys

1985 ◽  
Vol 58 ◽  
Author(s):  
R. G. Rowe ◽  
J. A. Sutliff ◽  
E. F. Koch
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Titanium Aluminide ◽  
Melt Spinning ◽  
Room Temperature ◽  
Beta Transus ◽  
Processing Conditions ◽  
Room Temperature Ductility ◽  
Rapidly Solidified ◽  
Titanium Aluminide Alloys

ABSTRACTTitanium aluminide alloys with matrix compositions of essentially Ti3Al plus 0, 5, 7.5, and 10 a/o Nb and with and without rare earth elements for dispersoid formation were prepared. The alloys were rapidly solidified by melt spinning. Ribbon was consolidated by HIP and extrusion at temperatures below the beta transus temperatures of the alloys. The effects of processing conditions and dispersoid additions on room temperature ductility and fracture toughness were studied.

Online Spinning of Commingled Yarns-Equipment and Yarn Modification by Tailored Fibre Surfaces

2007 ◽  
Vol 334-335 ◽  
pp. 229-232 ◽  
Author(s):  
Edith Mäder ◽  
Christina Rothe ◽  
Harald Brünig ◽  
Thomas Leopold
Keyword(s):  
Melt Spinning ◽  
Processing Conditions ◽  
Polypropylene Film ◽  
Cooling Conditions ◽  
Processing Step ◽  
Polypropylene Yarn ◽  
Fundamental Research ◽  
Technological Processing ◽  
Commingled Yarns

A unique melt spinning equipment for E-glass is compatibly combined with a melt spinning extruder to manufacture commingled yarns. The in-situ commingling enables to combine homogeneously both glass and polypropylene filament arrays in one processing step and without fibre damage compared to commingling by air texturing. Best composite performance is achieved with a sizing for glass fibres consisting of aminosilane and maleic anhydride grafted polypropylene film former, which enable a good strand integrity with the polypropylene yarn. The results of fundamental research on variation of technological processing conditions like diameter ratios, draw ratios, variation of cooling conditions and arrangements of intermingling are reported for glass fibre/polypropylene systems.

Effects of Glycerol on Melt Spinning of Polyacrylonitrile Copolymer and Tetrapolymer

2020 ◽  
Vol 21 (2) ◽  
pp. 376-383
Author(s):  
Yeong Min Im ◽  
Hye Mi Choi ◽  
A. Joseph Nathanael ◽  
Min Hye Jeong ◽  
Seung O. Lee ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Polyacrylonitrile Copolymer

scholarly journals Effects of melt spinning parameters on polypropylene hollow fiber formation

2020 ◽  
Vol 15 ◽  
pp. 155892501989968
Author(s):  
Rebecca Ruckdashel ◽  
Eunkyoung Shim
Keyword(s):  
Tensile Properties ◽  
Hollow Fiber ◽  
Melt Spinning ◽  
Tensile Modulus ◽  
Fiber Spinning ◽  
Fiber Formation ◽  
Processing Conditions ◽  
Quench Rate ◽  
Fiber Structure ◽  
Spinning Speed

The objective of this research was to explore the effects of processing conditions on hollow fiber spinning, specifically to look at how differences in solidification impact hollow and solid fiber structures. Polypropylene hollow fibers were melt-spun with a four-segmented arc (4C) die under the wide ranges of spinning conditions (0.25–0.83 g/min of polymer mass throughput per a fiber, 500–2000 m/min of spinning speed, and 5%–100% quench rate). Fiber structure was explored through thermal, geometric, and tensile properties. Fiber hollowness depends on all spinning parameters studied (mass throughput, spinning speed, and quench rate). Increasing the quench rate resulted in the fiber solidifications closer to the spinneret. This leads to higher hollowness but also affected fiber tensile properties. When hollow and solid fibers were compared at constant quench, the hollow fiber solidified faster than solid fiber. The crystallinity of the fibers remained similar, but the tensile modulus was higher for hollow fiber than for solid fiber.

EM of rapidly solidified permanent magnets

1992 ◽  
Vol 50 (1) ◽  
pp. 198-199
Author(s):  
Raja K. Mishra
Keyword(s):  
Melt Spinning ◽  
Permanent Magnets ◽  
Dark Field Image ◽  
Dark Field ◽  
Maximum Energy ◽  
Quench Rate ◽  
Maximum Energy Product ◽  
Energy Product ◽  
Annular Dark Field ◽  
Rapidly Solidified

The discovery of a new class of permanent magnets based on Nd2Fe14B phase in the last decade has led to intense research and development efforts aimed at commercial exploitation of the new alloy. The material can be prepared either by rapid solidification or by powder metallurgy techniques and the resulting microstructures are very different. This paper details the microstructure of Nd-Fe-B magnets produced by melt-spinning.In melt spinning, quench rate can be varied easily by changing the rate of rotation of the quench wheel. There is an optimum quench rate when the material shows maximum magnetic hardening. For faster or slower quench rates, both coercivity and maximum energy product of the material fall off. These results can be directly related to the changes in the microstructure of the melt-spun ribbon as a function of quench rate. Figure 1 shows the microstructure of (a) an overquenched and (b) an optimally quenched ribbon. In Fig. 1(a), the material is nearly amorphous, with small nuclei of Nd2Fe14B grains visible and in Fig. 1(b) the microstructure consists of equiaxed Nd2Fe14B grains surrounded by a thin noncrystalline Nd-rich phase. Fig. 1(c) shows an annular dark field image of the intergranular phase. Nd enrichment in this phase is shown in the EDX spectra in Fig. 2.

Formation of defects in implanted hipox-structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1406-1407
Author(s):  
Peter Pegler ◽  
N. David Theodore ◽  
Ming Pan
Keyword(s):  
High Pressure ◽  
Cross Section ◽  
Semiconductor Devices ◽  
Silicon Substrates ◽  
Processing Conditions ◽  
Pressure Oxidation ◽  
Deep Trench ◽  
Local Oxidation ◽  
Trench Isolation ◽  
And Behavior

High-pressure oxidation of silicon (HIPOX) is one of various techniques used for electrical-isolation of semiconductor-devices on silicon substrates. Other techniques have included local-oxidation of silicon (LOCOS), poly-buffered LOCOS, deep-trench isolation and separation of silicon by implanted oxygen (SIMOX). Reliable use of HIPOX for device-isolation requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of HIPOX-related stresses in the structures is of interest because structuraldefects, if formed, could electrically degrade devices.This investigation was performed to study the origin and behavior of defects in recessed HIPOX (RHIPOX) structures. The structures were exposed to a boron implant. Samples consisted of (i) RHlPOX'ed strip exposed to a boron implant, (ii) recessed strip prior to HIPOX, but exposed to a boron implant, (iii) test-pad prior to HIPOX, (iv) HIPOX'ed region away from R-HIPOX edge. Cross-section TEM specimens were prepared in the <110> substrate-geometry.

In situ TEM observations of melting in nanosized eutectic Pb-Cd inclusions embedded in Al

1996 ◽  
Vol 54 ◽  
pp. 986-987
Author(s):  
S. Hagège ◽  
U. Dahmen ◽  
E. Johnson ◽  
A. Johansen ◽  
V.S. Tuboltsev
Keyword(s):  
Electron Microscope ◽  
Melt Spinning ◽  
Ternary Alloys ◽  
Solid Matrix ◽  
Eutectic System ◽  
In Situ Tem ◽  
In Situ Observation ◽  
Orientation Relationships ◽  
Transmission Electron

Small particles of a low-melting phase embedded in a solid matrix with a higher melting point offer the possibility of studying the mechanisms of melting and solidification directly by in-situ observation in a transmission electron microscope. Previous studies of Pb, Cd and other low-melting inclusions embedded in an Al matrix have shown well-defined orientation relationships, strongly faceted shapes, and an unusual size-dependent superheating before melting.[e.g. 1,2].In the present study we have examined the shapes and thermal behavior of eutectic Pb-Cd inclusions in Al. Pb and Cd form a simple eutectic system with each other, but both elements are insoluble in solid Al. Ternary alloys of Al (Pb,Cd) were prepared from high purity elements by melt spinning or by sequential ion implantation of the two alloying additions to achieve a total alloying addition of up to lat%. TEM observations were made using a heating stage in a 200kV electron microscope equipped with a video system for recording dynamic behavior.

Electron spectroscopic imaging (ESI) on multiphase polymer materials

1989 ◽  
Vol 47 ◽  
pp. 348-349
Author(s):  
H.-J. Cantow ◽  
M. Kunz ◽  
M. Möller
Keyword(s):  
Energy Loss ◽  
Melt Spinning ◽  
Chromatic Aberration ◽  
Element Distribution ◽  
Polymer Materials ◽  
Specific Energy Loss ◽  
Transmission Electron ◽  
Multicomponent Polymer ◽  
Diffraction Patterns ◽  
Image Planes

In transmission electron microscopy the natural contrast of polymers is very low. Thus the contrast has to be enhanced by staining with heavy metals. The resolution is limited by the size of the staining particles and by the fact that electrons with different energy are focused in different image planes due to the chromatic aberration of the magnetic lenses. The integration of an electron energy loss spectrometer into the optical coloumn of a transmission electron microscope offers the possibility to use monoenergetic electrons and to select electrons with a certain energy for imaging. Thus contrast and resolution are enhanced. By imaging only electrons with an element specific energy loss the element distribution in the sample can be obtained. In addition, elastic bright field images and diffraction patterns yield excellent resolution. Some applications of the method on multicomponent polymer materials are discussed.Bulk polymer samples were prepared by ultramicrotoming at room temperature or well below the glass transition temperature. Very thin films for the direct observation of the structure in semicrystalline polymers were obtained by melt-spinning. Specimens were examined with a ZEISS CEM 902 operated at 80 kV.

Sign in / Sign up

Export Citation Format

Share Document