Poly fiber formation

Fibers in which the basic chemical units have been formed by chemical synthesis, followed by fiber formation, are called synthetic fibers. Examples include nylon, carbon, boron fibers, organic fibers, ceramic fibers, and metallic fibers. Among all commercially available fibers, Kevlar fibers exhibit high strength and modulus. (Kevlar is a DuPont trademark for poly [p-phenylene diamine terephthalamide].) It is an aromatic polyamide (aramid) in which at least 85% of the... 

In the case of fibrinogen, the slow time course of adsorption onto poly(HEMA)/Silastic and Silastic make attempts at obtaining true equilibrium adsorption isotherms difficult because the fibrinogen solutions will undergo slow fiber formation unless protected from bacterial degradation. Also, storage of such solutions is a problem since fibrinogen... 

Gupta, P., C. Elkins, T.E. Long, and G.L. Wilkes. Electrospinning of linear homopolymers of poly (methyl methacrylate) exploring relationships between fiber formation, viscosity, molecular weight and concentration in a good solvent. Polymer 46(13) (2005) 4799 810. 

Shen X-W, Yang Y, Jian J, Wu Q, Chen G-Q (2009) Production and characterization of homopolymer poly(3-hydroxyvalerate) (PHV) accumulated by wild type and recombinant Aeromonas hydrophila strain 4AK4. Bioresour Technol 100 4296-4299 Shenoy SL, Bates WD, Frisch HL, Wnek G (2005a) Role of chain entanglements on fiber formation during electrospinning of polymer solutions good solvent, non-specific polymer-polymer interaction limit. Polymer 46 3372-3384... 

Dong, H., Strawhecker, KE., Snyder, J.F., Orlicki, J.A., Reiner, R.S., Rudie, A.W. Cellulose nanocrystals as a reinforcing material for electrospun poly(methyl methacrylate) fibers formation, properties and nanomechanical characterization. Carbohydr. Polym. 87, 2488-2495 (2012)... 

Poly(VPGVG) is a substrate for the natural enzyme prolyl hydroxylase, which uses molecular oxygen and the cofactor vitamin C (ascorbic acid) for the reaction. Figure 7.49 also contains the temperature profile for fiber formation that results from hydroxylation by prolyl hydroxylase. When 100% hydroxylated as in poly(Val-Hyp-Gly-Val-Gly), T, is about 65° C. An estimated 1 % hydroxylation by prolyl hydroxylase results in a value of T, of about 40°C. As shown in Figure 5.1C, T is just at the very onset of the aggregation, such that raising the value of T, from about 30° to about 40° C would prevent assembly into fibers at body temperature. Prolyl hydroxylation of the polypentapeptide model of elastin impairs fiber formation at physiological temperature. 

Some researchers studied the effect of solution viscosity on the formation of PANI-CSA fibers [203,204]. They found that a stable polymer droplet was formed with adding 2 wt % poly(ethylene oxide) (PEO) into solution, whereas no fiber formation of PANI/CSA occurred in chloroform without PEO addition. 

The first fibers from a thermotropic liquid crystalline melt whose properties were reported were spun from a copolyester of para-hydroxybenzoic acid (PHB) and poly-ethyleneterephthalate (PET) by workers at Tennessee Eastman Co. The preparation of the copolymer proceeds in two stages. First, para-acetoxybenzoic acid is reacted with poly-ethyleneterephthalate in an acidolysis step to give a copolyester prepolymer, which in the second step is condensed further to a higher degree of polymerization suitable for fiber formation. 

Kenawy E. R., Bowlin G. L., Mansfield K., Layman J., Simpson D. G., Sanders E. H. (2002), Release of tetracychne hydrochloride from electrospun poly(ethylene-co-vinylacetate), polylactic acid and a blend , J Controlled Release, 81, 57-64. Scopelianos A. G. (1996), Pizoelectric biomedical device, US Patent, 5522879. Larrondo L., Manley R. (1981), Electrostatic fiber spinning from polymer melts. I. Experimental observation on fiber formation and properties , J Polym Sci Polym Phys Ed, 19, 909-920. 

The resihency and dyeabihty of poly(vinyl alcohol) fibers is improved by a process incorporating -hydroxybenzaldehyde to provide a site for the formation of a stable Mannich base. Hydroxyl groups on the fiber are converted to acetal groups by -hydroxybenzaldehyde. Subsequent reaction with formaldehyde and ammonia or an alkylamine is rapid and forms a stable Mannich base that is attached to the polymer backbone (94). 

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