scholarly journals New Approach to Preparation of Heat-Resistant “Lola-M” Fiber

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3490 ◽  
Author(s):  
Igor I. Ponomarev ◽  
Ivan Y. Skvortsov ◽  
Yulia A. Volkova ◽  
Ivan I. Ponomarev ◽  
Lydia A. Varfolomeeva ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Ternary Mixture ◽  
Average Diameter ◽  
Fiber Spinning ◽  
Wet Spinning ◽  
New Approach ◽  
Elongation At Break ◽  
Heat Resistant ◽  
Polymer Reaction ◽  
Spinning Process

A new approach to the synthesis of polynaphthoylenebenzimidazoles and heat resistant fiber spinning has been developed using an environmentally friendly and energy efficient method, which operates with solutions of pre-polymers based on 3,3’,4,4’-tetraaminodiphenyl ether and 1,4,5,8-naphthalenetetracarboxylic acid dianhydride in N-methylpyrrolidone. Rheological properties of polymer reaction solutions and appropriate coagulant mixtures were investigated for further wet spinning process. The coagulation process was investigated through microscopic observation of solution droplets which imitate jet/fiber cross section surrounded with coagulants of different composition. For the case of the most optimal viscoelastic properties of dopes the best coagulant was found to be a ternary mixture ethanol/water/NMP (20/10/70). Fibers were prepared through the wet spinning from pre-polymers of various molecular weight characterized by intrinsic viscosity. As a result, complex yarns were spun, and their morphology was characterized and mechanical properties were measured. The strength of ~300 MPa and elastic modulus of ~2 GPa and elongation at break of ~20% were reached for the best fibers at average diameter of ~20 µm. After heat treatment “Lola-M” fibers do not burn and do not support combustion in open flame.

Preparation and Characterization of Polysulfone/Ru Nanocluster Hybrid Hollow Fiber Membrane

2014 ◽  
Vol 1053 ◽  
pp. 357-363
Author(s):  
Chun Yan Jiang ◽  
Cheng Yan ◽  
Shu Zheng Liu ◽  
Yu Hua Zhang ◽  
Ai Qing Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Average Diameter ◽  
Wet Spinning ◽  
Hybrid Membranes ◽  
Fiber Membrane ◽  
Structures And Properties ◽  
Spinning Process

Polysulfone/Ru nanocluster hybrid hollow fiber membranes with different Ru content were fabricated by the dry/wet spinning process. The structures and properties of Ru nanocluster, PSF hollow films and PSF/Ru hybrid hollow fiber films were characterized by TEM, SEM, XPS, XRD, TGA, etc. The results showed that the Ru particles, which may coordinate with O and S in polysulfone, distributed symmetrically with an average diameter about 1~2 nm. More finger-like pores of the hybrid membranes were obtained after adding Ru nanocluster, and the thermal properties of the membranes increased while the mechanical properties decreased.

scholarly journals The effect of terminal globular domains on the response of recombinant mini-spidroins to fiber spinning triggers

2020 ◽  
Author(s):  
William Finnigan ◽  
Aled D. Roberts ◽  
Nigel S. Scrutton ◽  
Rainer Breitling ◽  
Jonny J. Blaker ◽  
...  
Keyword(s):  
Spider Silk ◽  
Fiber Spinning ◽  
Fiber Formation ◽  
Wet Spinning ◽  
Salting Out ◽  
Essential Step ◽  
Spinning Process ◽  
Repetitive Protein ◽  
Terminal Domains

AbstractSpider silk spidroins consist of long repetitive protein strands, flanked by globular terminal domains. The globular domains are often omitted in recombinant spidroins, but are thought to be essential for the spiders’ natural spinning process. Mimicking this spinning process could be an essential step towards producing strong synthetic spider silk. Here we describe the production of a range of mini-spidroins with both terminal domains, and characterize their response to a number of biomimetic spinning triggers. Our results suggest that the inclusion of the terminal domains is needed to match the response to shear that native spidroins exhibit. Our results also suggest that a pH drop alone is insufficient to trigger assembly in a wet-spinning process, and must be combined with salting-out for effective fiber formation. With these insights, we applied these assembly triggers for relatively biomimetic wet spinning. This work adds to the foundation of literature for developing improved biomimetic spinning techniques, which ought to result in synthetic silk that more closely approximates the unique properties of native spider silk.

scholarly journals Compositions Based on PAN Solutions Containing Polydimethylsiloxane Additives: Morphology, Rheology, and Fiber Spinning

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 815
Author(s):  
Valery G. Kulichikhin ◽  
Ivan Y. Skvortsov ◽  
Lydia A. Varfolomeeva
Keyword(s):  
Phase Separation ◽  
Continuous Medium ◽  
Viscosity Ratio ◽  
Fiber Spinning ◽  
Wet Spinning ◽  
Diffusion Front ◽  
Molecular Weights ◽  
Effect Of Additives ◽  
Coalescence Rate ◽  
Spinning Process

The effect of additives of polydimethylsiloxanes (PDMS) with various molecular weights on the morphology and rheological behavior of polyacrylonitrile (PAN) solutions in dimethyl sulfoxide has been analyzed. It was shown that only partial compatibility of the PDMS with the lowest molecular weight member of the homologous series studied—hexamethyldisiloxane—with PAN solution takes place. All other PDMS samples form emulsions with PAN solutions. The coalescence rate of PDMS drops depends on the viscosity ratio of the disperse phase and the continuous medium, which determines both the duration of dispersion preparation and the conditions for processing emulsions into fibers and films. An anomalous change in viscosity for a series of emulsions with different concentrations of additives, associated with the slippage, was detected. The relaxation properties of emulsions “feel” macro-phase separation. Modeling of the wet spinning process has shown that the morphology of the deposited solution drop reflects the movement of the diffusion front, leading to the gathering droplets in the center of the deposited formulation drop or to their localization in a certain arrangement. It was shown that the emulsion jets upon stretching undergo phase separation.

Theoretical and experimental investigation of the wet-spinning process for mechanically strong carbon nanotube fibers

2021 ◽  
Vol 412 ◽  
pp. 128650
Author(s):  
Hyeon Dam Jeong ◽  
Seo Gyun Kim ◽  
Gyeong Min Choi ◽  
Minji Park ◽  
Bon-Cheol Ku ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Carbon Nanotube ◽  
Wet Spinning ◽  
Spinning Process ◽  
Carbon Nanotube Fibers

CELL LADEN ALGINATE/ALBUMIN HYDROGEL FIBERS FOR POTENTIAL SKIN TISSUE ENGINEERING APPLICATIONS

2018 ◽  
Vol 30 (06) ◽  
pp. 1850045
Author(s):  
Maria Grazia Cascone ◽  
Elisabetta Rosellini ◽  
Simona Maltinti ◽  
Andrea Baldassare ◽  
Luigi Lazzeri
Keyword(s):  
Tissue Engineering ◽  
A549 Cells ◽  
Average Diameter ◽  
Favorable Effect ◽  
Engineering Applications ◽  
Residual Amount ◽  
Spinning Process ◽  
Proliferation Ability ◽  
Alginate Fibers ◽  
Kinetics Of

Alginate hydrogel fibers are receiving a great attention for tissue engineering applications. However, an important limitation of alginate is that it does not provide cell adhesion motifs. In this work, albumin was blended with alginate to improve the compatibility of alginate fibers with cells. Cell laden alginate/albumin fibers, potentially usable for skin regeneration, were obtained through a spinning process, by extruding an alginate/albumin solution containing cells into a calcium chloride solution. Cell laden pure alginate fibers were prepared for comparison. Plain alginate and alginate/albumin fibers were also produced. Morphological, mechanical and functional properties of the produced fibers were investigated. In addition, the ability of the fibers to release albumin and to support the viability and growth of A549 cells embedded into them was studied. Fibers with a uniform shape and an average diameter within the range 550–570[Formula: see text][Formula: see text]m were produced. The water content was [Formula: see text]% for alginate fibers, and [Formula: see text]% for alginate/albumin fibers. Stress–strain tests showed, up to a strain value of 20%, the same Young’s modulus for the produced fibers, regardless of the presence of albumin. Overall, obtained results demonstrated that morphology, size, hydrophilicity and mechanical properties were not affected by albumin. Albumin was gradually released over a period of 4 days, with a residual amount (13%) remaining into the fibers. Viability test was carried out on A549 cells, laden inside alginate and alginate/albumin fibers, to evaluate cell proliferation ability. A favorable effect of albumin on the loaded cells was evidenced by a faster kinetics of growth.

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.

A Novel Approach to Nanoscale Materials Synthesis Using Industrial Laser Processing of Organosilazane Liquid Precursors

1990 ◽  
Vol 206 ◽  
Author(s):  
Tongsan D. Xiao ◽  
Peter R. Strutt ◽  
Kenneth E. Gonsalves
Keyword(s):  
Ceramic Powder ◽  
Average Diameter ◽  
Current Approach ◽  
Powder Materials ◽  
Materials Synthesis ◽  
Laser Plume ◽  
New Approach ◽  
Novel Approach ◽  
Liquid Precursors ◽  
Short Time

ABSTRACTA new approach has been developed for the synthesis of nanoscale ceramic powder materials from liquid organosilazane precursors. This technique, by exploiting fast kinetic chemical and physical reactions, makes it possible to synthesize significant quantities of material in a relatively short time. In the current approach aerosols of a silazane monomer, (CH3SiHNH)n, (n = 3 or 4), of mol. wt. 280–320, are injected into the beam of a cw industrial CO2 laser to obtain nanoscale ceramic powders. Injection of the aerosol into the laser-beam results in a high-temperature plume. Rapid condensation of the molecular precursor species emerging from the laser plume results in the formation of preceramic polymer particles, with an average diameter of 62 nm. One attractive feature of this process is that 70 wt.% of the liquid precursor is converted into nanoscale powders. Another feature is that only a further 10 wt.% loss occurs during post thermal treatment to form the end-product.

A new approach to design energy efficient water allocation networks

2009 ◽  
Vol 29 (11-12) ◽  
pp. 2302-2307 ◽  
Author(s):  
Xiao Feng ◽  
Yucai Li ◽  
Renjie Shen
Keyword(s):  
Energy Efficient ◽  
Water Allocation ◽  
New Approach
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