Protein-based fibers

Silks are protein-based fibers produced by several arthropods, most notably silkworms and spiders. Silkworms produce silk to form cocoons within which they metamorphosize into moths. The 5000-year-old sericulture industry has domesticated the Bombyx mori silkworm and has perfected the art of unreeling these cocoons into their single-fiber components to be woven into fabrics. These silk fibers are fine and lustrous, giving them compelling textile properties. Wild silkworms such as Antheraea paphia still exist and produce silks with different properties (e.g., crystallinity, aoss-sectional shape, color, dyeability) ... 

Figure 9.20. Elastic protein-based fibers a few hundred micrometers in diameter, prepared by extrusion and chemical cross-linking. Impressive mechanical properties of elastic modulus at 20%...

A fiber is a long, thin filament of a material. Fiber technologies are used to produce fibers from different materials that are either obtained from natural sources or produced synthetically. Natural fibers are either ceUulose-based or protein-hased, depending on their source. All cellulosic fibers come from plant sources, while protein-based fibers such as sUk and wool are exclusively from animal sources hoth fiber types are referred to as biopolymers. Synthetic fibers are manufectured from synthetic polymers, such as nylon, rayon, polyaramides, and polyesters. An... 

Another significant effort in developing high strength spider silk protein-based fibers under the trademark Biosteel is by Nexia Biotechnologies Inc. [54]. 

Silkworm silk is another protein-based fiber produced naturally by the silkworm, B. Mori or other varieties of moth, and it is the only naturally and commercially produced continuous filament. Silkworm silk fiber is composed of a fibroin core and a sericin casing, and is relatively rigid because the sericin causes the filaments to adhere to one another. After the desericin treatment (with alkali treatment) silk has high tenacity, high luster, and good dimensional stability. A triangle cross section is its typical stracture, which results in the luster of silkworm silk (Fig. 2.10). 

Ellis, G. D. Dimarcello, B. J. Bradshaw, D. J. Preparation of a dye for coloring protein-based fibers and cellulose-based materials from the oxidation byproducts of the manufacture of a triphenylmethane dye. Eur. Pat. Appl. EP 909794, 1999 Chem. Abstr. 1999, 130, 313189. 

Lastly, synthetic varieties of textiles are present primarily in apparel and are either petroleum-based or blends with natural fibers. Polyester fibers, aramid fibers, acrylics, nylon, polyurethane, olefins (hydrophobic), polylactide (hydrophilic), milk protein-based fibers, and carbonization-based fibers all constitute synthetics which require some level of surface-modification. This includes nonwovens, structures bonded together by entangling fiber or filaments mechanically, thermally, or chemically. 

The structures of some natural protein-based materials, such as silk and wool, result in strong, tough fibers. Spiders and silkworms use proteins as a structural material of remarkable strength (Fig. 19.22). Chemists are duplicating nature by making artificial spider silk (Fig. 19.23), which is one of the strongest fibers known. 

F. K. Ogasawara, Y. Wang, and D. R. Bobbitt, Dynamically modified, biospecific optical fiber sensor for riboflavin binding protein based on hydrophobically associated 3-octylriboflavin, Anal Chem. 

To extend the application area of silk proteins-based materials, blending the fibroin with other natural macromolecules and synthetic polymers, or even manufacturing composites with silk fibers are a few of the possible strategies. 

The first demonstration of the industrial importance of heme peroxidases in grafting applications has been the development of hybrid resins from renewable sources to replace phenol-formaldehyde based resins. Phenolic resins are widely used in surface coatings, adhesives, laminates, molding, friction materials, abrasives, flame retardants, carbon membranes, glass fiber laminates, fiberboards, and protein-based wood adhesives, [5]. Table 7.1 and Fig. 7.2 summarize some of the... 

For 10 years, this elegant restaurant located in the Santa Monica shopping district has stayed current on health trends. Their meals are high in fiber and low in fat, contain no cholesterol, and have a hearty protein base. They use only organically grown produce and whole foods, and use no animal or dairy products, eggs, sugar, honey, artificial sweeteners, or refined flour. And they even filter and purify their water. 

In patients with acute HE, protein is withheld or limited to 10 to 20 g/day while maintaining the total caloric intake, nntU the clinical situation improves. Titrate protein based on tolerance, increasing intake in increments of 10 to 20 g/day every 3 to 5 days to a total of 0.8 to 1 g/kg per day. In patients with chronic HE, restrict protein to 40 g/day. Consider the addition of dietary fiber to animal-source protein diets. 

Dyes 8-12 belong to the family of azo conqiounds, while 13 is a formazan dye. Formazan dyes are more commonly used as dyes for cellulose-based fibers, in which case they would contain a reactive moiety, and are 1 1 Cu-complexed dyes (1 metal per dye molecule) (6). Metal complexes of the 1 2 type (1 metal per 2 dye molecules) are used for polyamide and protein fibers. In the latter case, Cr and Co complexes... 

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