Stability Analysis of the Fiber Spinning Process

1972 ◽  
Vol 16 (3) ◽  
pp. 519-533 ◽  
Author(s):  
J. R. A. Pearson ◽  
Y. T. Shah
Keyword(s):  
Stability Analysis ◽  
Fiber Spinning ◽  
Spinning Process

scholarly journals Hierarchical spidroin micellar nanoparticles as the fundamental precursors of spider silks

2018 ◽  
Vol 115 (45) ◽  
pp. 11507-11512 ◽  
Author(s):  
Lucas R. Parent ◽  
David Onofrei ◽  
Dian Xu ◽  
Dillan Stengel ◽  
John D. Roehling ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Spider Silk ◽  
Fiber Spinning ◽  
Fiber Formation ◽  
Natural Material ◽  
Physical Form ◽  
Spinning Process ◽  
Black Widow Spiders ◽  
Spider Silks

Many natural silks produced by spiders and insects are unique materials in their exceptional toughness and tensile strength, while being lightweight and biodegradable–properties that are currently unparalleled in synthetic materials. Myriad approaches have been attempted to prepare artificial silks from recombinant spider silk spidroins but have each failed to achieve the advantageous properties of the natural material. This is because of an incomplete understanding of the in vivo spidroin-to-fiber spinning process and, particularly, because of a lack of knowledge of the true morphological nature of spidroin nanostructures in the precursor dope solution and the mechanisms by which these nanostructures transform into micrometer-scale silk fibers. Herein we determine the physical form of the natural spidroin precursor nanostructures stored within spider glands that seed the formation of their silks and reveal the fundamental structural transformations that occur during the initial stages of extrusion en route to fiber formation. Using a combination of solution phase diffusion NMR and cryogenic transmission electron microscopy (cryo-TEM), we reveal direct evidence that the concentrated spidroin proteins are stored in the silk glands of black widow spiders as complex, hierarchical nanoassemblies (∼300 nm diameter) that are composed of micellar subdomains, substructures that themselves are engaged in the initial nanoscale transformations that occur in response to shear. We find that the established micelle theory of silk fiber precursor storage is incomplete and that the first steps toward liquid crystalline organization during silk spinning involve the fibrillization of nanoscale hierarchical micelle subdomains.

Synchrotron Radiation SAXS Study of Microvoids Structure of PAN Fiber during Spinning Process

2013 ◽  
Vol 634-638 ◽  
pp. 2923-2927
Author(s):  
Xue Ping Gao ◽  
Bo Zhu ◽  
Yang Chen
Keyword(s):  
Synchrotron Radiation ◽  
Aspect Ratio ◽  
Fiber Spinning ◽  
Fiber Axis ◽  
Coagulation Bath ◽  
Radius Of Gyration ◽  
Scattering Intensity ◽  
Pan Fiber ◽  
Washing Process ◽  
Spinning Process

The microvoids structure changes of the PAN fibers were characterized by synchrotron radiation SAXS. The synchrotron radiation SAXS patterns and the changes of scattering intensity show that after various fiber spinning process, microviods were gradually oriented in parallel with the fiber axis, and the number of the microvoids was decreased. Fankuchen tangent method was used to deal with the experimental data. After the first coagulation bath, a large number of microvoids were formed in fibers, the aspect ratio was close to 1.0, the shape was nearly spherical, and the radius of gyration (Rg) was 14nm. During plasticizing drawing and washing process, the dimension of microvoids was decreased. Rg was 10nm, the aspect ratio reached 1.6, the shape of the microvoids was nearly ellipsoidal, and the microvoids exhibited preferred orientation along the fiber axis direction. After the processes drying collapsing and drawing in vapor, the scattering intensity of fiber drastically decreased, the number of microvoids significantly reduced, Rg turned to 12.9nm, and the aspect ratio reached 1.9. During heat setting process, the aspect ratio of microvoids reduced, but Rg slightly increased.

scholarly journals Nozzle design in a fiber spinning process for a maximal pressure gradient

2013 ◽  
Vol 17 (5) ◽  
pp. 1529-1532 ◽  
Author(s):  
Zhanping Yang ◽  
Li Zhang ◽  
Rouxi Chen ◽  
Ji-Huan He ◽  
Jian-Hua Cao ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Optimal Condition ◽  
Fiber Spinning ◽  
Nozzle Design ◽  
Geometrical Constraint ◽  
Spinning Process ◽  
Geometrical Form ◽  
Maximal Pressure

The thickness of a spinneret is always a geometrical constraint in nozzle design. The geometrical form of a nozzle has a significant effect on the subsequent spinning characteristics. This paper gives an optimal condition for maximal pressure gradient through the nozzle.

NUMERICAL EVIDENCE FOR THE NON-EXISTENCE OF STATIONARY SOLUTIONS OF THE EQUATIONS DESCRIBING ROTATIONAL FIBER SPINNING

2008 ◽  
Vol 18 (10) ◽  
pp. 1829-1844 ◽  
Author(s):  
THOMAS GÖTZ ◽  
AXEL KLAR ◽  
ANDREAS UNTERREITER ◽  
RAIMUND WEGENER
Keyword(s):  
Fluid Velocity ◽  
Stationary Solutions ◽  
Fiber Spinning ◽  
Inviscid Limit ◽  
Point Boundary ◽  
Viscous Stress ◽  
Reference Case ◽  
Spinning Process ◽  
Inviscid Case ◽  
Good Agreement

The stationary, isothermal rotational spinning process of fibers is considered. The investigations are concerned with the case of large Reynolds (δ = 3/ Re ≪ 1) and small Rossby numbers (ε ≪ 1). Modelling the fibers as a Newtonian fluid and applying slender body approximations, the process is described by a two-point boundary value problem of ODEs. The involved quantities are the coordinates of the fiber's centerline, the fluid velocity and viscous stress. The inviscid case δ = 0 is discussed as a reference case. For the viscous case δ > 0 numerical simulations are carried out. Transfering some properties of the inviscid limit to the viscous case, analytical bounds for the initial viscous stress of the fiber are obtained. A good agreement with the numerical results is found. These bounds give strong evidence, that for δ > 3ε2 no physical relevant stationary solution can exist.

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