An intrinsic viscosity‐molecular weight relation for polyacrylonitrile
TL;DR: Weight-average molecular weights and intrinsic viscosities in dimethyl formamide at 25° have been measured for four unfractionated low-conversion acrylonitrile polymers covering the molecular weight range 30 to 250 thousand as mentioned in this paper.
Abstract: Weight-average molecular weights and intrinsic viscosities in dimethyl formamide at 25° have been measured for four unfractionated low-conversion acrylonitrile polymers covering the molecular weight range 30 to 250 thousand. The results follow the equation:
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01 Jun 1963
443 citations
TL;DR: In this article, an in-depth review of the mechanical properties of electrospun fibers is presented, focusing on methodologies to generate high strength and high modulus nanofibers.
Abstract: Electrospinning is a rapidly growing polymer processing technology as it provides a viable and simple method to create ultra-fine continuous fibers. This paper presents an in-depth review of the mechanical properties of electrospun fibers and particularly focuses on methodologies to generate high strength and high modulus nanofibers. As such, it aims to provide some guidance to future research activities in the area of high performance electrospun fibers.
231 citations
Cites background from "An intrinsic viscosity‐molecular we..."
...Moreover, as the estimated coil size of a PAN molecule with a molar mass of 150,000 is of the order of 30–40 nm based on its mean square end-to-end distance (<R(2)> = C∞ n l(2)) [95,96] it is also difficult to imagine the extreme confinement effects in 138 nm fibers which are necessary to explain such property improvement....
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22 Feb 1999
137 citations
TL;DR: This work simulates free-radical homopolymerizations under restricted polymerization conditions with real-world examples of several different types of monomer systems.
Abstract: Several models have been proposed in the literature over the last two decades in order to simulate free-radical homopolymerizations. However, most of these models deal with one specific monomer system, usually under restricted polymerization conditions.
97 citations
TL;DR: In this article, the influence of ionic liquids on free radical polymerization of methyl methacrylate (MMA), acrylonitrile (AN) and 1-vinyl-3-ethylimidazolium salts (ViEtIm+)Y− was investigated.
Abstract: Various 1,3-dialkylimidazolium and tetraalkylphosphonium ionic liquids (ILs), including novel ones, have been studied as reaction media for free radical polymerization of methyl methacrylate (MMA), acrylonitrile (AN) and 1-vinyl-3-ethylimidazolium salts (ViEtIm+)Y−. The influence of IL's nature upon the polymer formulation was investigated. The use of different ionic liquids allows not only to obtain the polymers with high molecular weight (PMMA, up to 5,770,000 g/mol; PAN, up to 735,000 g/mol and poly[(ViEtIm+)Y−], up to 1,130,000 g/mol) in high yields, but also to control the polymerization rate and molecular mass. The physicochemical characteristics, including mechanical properties, thermal stability and heat-resistance of the obtained polymers were studied in order to compare with those of polymers prepared in a traditional media. It was found that elongation, tensile modulus and strength of PAN, which was synthesized in ionic liquid, are reliatively higher. The influence of IL's nature upon their ionic conductivity and the formation of conductive polymers from molten-salt-type vinyl monomers was investigated. Molecular design of the polymers simultaneously with the influence of IL's nature in order to achieve higher ionic conductivity is discussed. Flexible, transparent polymer films, obtained in different ways, show relatively high ionic conductivity (of about 10−5 S cm−1 at 20°C). Copyright © 2006 John Wiley & Sons, Ltd.
96 citations