China
Africa
Explore chapters and articles related to this topic
Evolution of Hemodialysis Technology
Published in Sirshendu De, Anirban Roy, Hemodialysis Membranes, 2017
Various companies use different base polymers to spin dialysis grade membranes. Regenerated cellulose was quite popular initially. Membrana manufactured two products using this polymer with the commercial names Cuprophan and Bioflux. They have a small wall thickness, varying from 5 to 17 μm. The advantages of these membranes are low cost, good solute removal, and satisfactory performance based on Kt/v. Major disadvantages associated with these membranes are poor removal capacity of middle-molecular-weight solutes, inferior biocompatibility, lower ultrafiltration coefficient (KUF), and difficulty in conducting convection mode of dialysis due to lower wall thickness. Bioflux membranes had a larger pore diameter (7.23 Å). These membranes had several advantages over Cuprophan in terms of higher KUF and KoA, satisfactory removal of middle-molecular-weight solutes, and high mechanical strength. The Asahi/Tejni/Teruned/Toyobo companies had a product based on regenerated cellulose known as Cuprammonium Rayon. These membranes have an asymmetric structure, with a wall thickness of 9–26 μm, with higher biocompatibility. They have a larger pore size due to the use of PES as an additive, facilitating the removal of middle-molecular-weight solutes and can be categorized as high-flux dialysis membranes but with inferior biocompatibility.
Medical textiles
Published in Textile Progress, 2020
Viscose rayon and its associated industry is the oldest of the existing man-made fibre businesses (slightly older and more extensive than that of cuprammonium rayon) with roots stretching back to the late 19th century. A fibre made from regenerated cellulose, the starting material is purified wood pulp from spruce or eucalyptus trees, but it can also be produced from parts of other plants with a high cellular cellulose content such as soy plant stems, bamboo and sugar cane; when used, these other cellulose sources are often mentioned in the promotional literature presumably with the purpose of making the resulting viscose rayon products sound more acceptable. In fact the process, once the cellulose fibre pulp has been prepared, is the same as for wood pulp from trees. As for wood pulp, the original pulp is purified to remove lignin and undesirable colourants then temporarily chemically modified into sodium cellulose xanthate to render it soluble in sodium hydroxide solution prior to spinning; the syrupy so-called viscose solution is extruded into an acidic coagulating bath (wet-spun) to regenerate the cellulose and yield continuous filaments of viscose rayon. The filaments are then drawn and washed before winding, and depending upon the method of manufacture and extent of drawing, different physical and mechanical properties can be provided to the resulting fibre [94].
A review: can waste wool keratin be regenerated as a novel textile fibre via the reduction method?
Published in The Journal of The Textile Institute, 2022
For keratin to be used in textile applications, the most relevant technique is wet spinning of the solution. This technique (Figure 11) involves pumping a solution through a spinneret into a coagulating bath containing a non-solvent, wherein the non-solvent removes the solvent resulting in a solidified filament. The polymer is then drawn off as continuous filaments over rollers. The process is preferred for polymers that are not stable for other spinning conditions as it is considered more gentle, and it is often used for man-made fibres such as cuprammonium rayon, acrylic, nylon, and spandex fibres (Ozipek & Karakas, 2014; Puppi & Chiellini, 2017). The wet spinning process is adaptable to different scales (Puppi & Chiellini, 2017).
Evolution in the surface modification of textiles: a review
Published in Textile Progress, 2018
Ayoub Nadi, Aicha Boukhriss, Aziz Bentis, Ezzoubeir Jabrane, Said Gmouh
The production of traditional textiles can be considered to have been developed through three industrial revolutions: The mechanical revolution in the eighteenth and nineteenth centuries in England with the invention of the spinning jenny by James Hargreaves in 1764 and the Jacquard loom by Joseph-Marie Jacquard in 1804.The chemical revolution in the latter half of the nineteenth century and throughout the twentieth century resulted not only in the development of synthetic dyes, but also regenerated-cellulose filament materials. The first of these, following Joseph Swan’s patented method for extruding fine filaments from nitro-cellulose in 1883, was developed commercially in the early 1890s by Hilaire de Chardonnet (whose product was therefore known as ‘Chardonnet Silk’) and others followed swiftly, with cuprammonium rayon made by dissolving cellulose in cuprammonium hydroxide then extruding filaments into dilute sulfuric acid (1899). The most-successful regenerated-cellulose filament materials however was viscose rayon, brought into industrial production by Cross and Bevan in the late 1890s. Modified cellulose filament materials such as cellulose acetate were eventually developed into filament form and emerged somewhat later (1921) when they were brought into production by Camille and Henri Dreyfus at British Celanese. The first synthetic fibres emerged in the mid-twentieth century period such as:Nylon 6-6 invented by Carothers at DuPont (1935);Polyester, invented by Whinfield and Dixon at the British Calico Printers association Ltd, its production by Imperial Chemical Industries in England as Terylene began in 1941;Acrylic, brought into production first by Du Pont (1950);Polypropylene (1957), following development of the isotactic form using Ziegler/Natta catalysts at Montecatini (now Montedison SpA) in 1954 andSpandex yarns, also by Du Pont (1958).