Casein-wool

Casein wool is prepared similarly to artifical horn. Casein is precipitated by dilute sulfuric acid at 20° C, then washed and pressed. The alkaline casein solution is subsequently spun at 50° C into an acid precipitation tank and the fiber is cross-linked with formaldehyde. 

Just as with natural wool, casein wool is sensitive to acids, alkalis, and heat, but possesses less wet strength. In addition, and unlike natural wool, casein wool deforms plastically. 

Among the modified proteins products hardened by means of formaldehyde may be mentioned. Such hardening processes are being increasingly applied in industry. The conversion of casein into artificial horn has been known for a long time the reaction may be of the type shown in Fig. 9, where two protein chains are connected by means of a CHg-group. It also seems likely that in the hardening of casein-wool (from milk) similar reactions play a part. 

Acid casein finds use in a variety of applications, including adhesives (mainly for paper and wood) and paper coatings. In these latter uses, the casein is applied as a dispersion in aqueous alkali. Casein fibre may be produced by forcing an alkaline dispersion through a spinneret into an acid coagulating bath the fibre (commonly termed casein wool ) was produced commercially during World War II in Italy and the USA but it is now of little... 

The sulfur amino acid content of soy protein can be enhanced by preparing plasteins from soy protein hydrolysate and sources of methionine or cystine, such as ovalbumin hydrolysate (plastein AB), wool keratin hydrolysate (plastein AC), or L-methionine ethyl ester [3082-77-7] (alkaU saponified plastein) (153). Typical PER values for a 1 2 mixture of plastein AC and soybean, and a 1 3 mixture of alkah-saponified plastein and soybean protein, were 2.86 and 3.38, respectively, as compared with 1.28 for the soy protein hydrolysate and 2.40 for casein. 

Proteins Egg, milk and casein, animal glue, silk, wool, vegetable proteins (e.g. garlic, beans), human and animal tissues (e.g. mummies) Paint binders, adhesives, textiles, commodities, parchment... 

Amino acid Egg white Egg yolk Casein Animal glue (collagen) Wool (keratin) Silk (fibroin) Garlic... 

Optically active substances are preferentially adsorbed by some optically active adsorbent. Thus Broadly and Easty (1951) found wool and casein to adsorb (+) mandelic acid from its aqueous solution. Some workers also successfully carried out resolution without using an active adsorbent. The alumina was found to be suitable for resolving diastereoisomers of (-) menthyl ( ) mandelate. 

Till this time, polymer science was largely empirical, instinctive, and intuitive. Several polymers were commercially available prior to World War I celluloid, shellac, Galalith (casein), Bakelite, and cellulose acetate plastics hevea rubber, cotton, wool, and silk rayon fibers Glyptal polyester coatings bitumen or asphalt, and coumarone-indene and petroleum resins. However, as evidenced by the chronological data shown in Table 1.1, there was little... 

Synthetic fibres made from proteins are Aralac from milk protein casein, Vicara from corn protein zein, and Saralon from peanut protein. These fibres look like wool and can also be dyed just like wool or silk is dyed. These fibres are blended with wool to add strength. 

Nashef et al. (41) also reported that the rate of 6 elimination from cystine was directly dependent on hydroxide ion concentration although the relationship was not linear perhaps because of the complexity of the reaction (Equation 7). Sternberg and Kim (20.) found the rate of lysinoalanine formation in casein to be dependent on hydroxide ion concentration. Touloupais and Vassiliadis (45) also found the rate of lysinoalanine formation in wool to be pH dependent. These workers did not measure the rate of 6 elimination, therefore the rate determining step is not known. These results on proteins appear to be in contradiction to those of Samuel and Silver (46) who reported that hydroxide ion concentration had no effect on the rate of 6 elimination from free phosphoserine between pH 7 and 13.5. Because of the effect... 

In previous papers, we have (a) reviewed elimination reactions of disulfide bonds in amino acids, peptides, and proteins under the influence of alkali (5) (b) analyzed factors that may operate during alkali-induced amino acid crosslinking and its prevention (6) (c) demonstrated inhibitory effects of certain amino acids and inorganic anions on lysinoalanine formation during alkali treatment of casein, soy protein, wheat gluten, and wool and on lanthionine formation in wool ( 7, 9) (d) demonstrated that... 

The raw materials used for the preperation of regenerated protein fibres may be milk, soyabeans, peanuts and zein. Sometimes alkaline solutions of gelatin, albumin and other raw materials like waste wool, silk and feathers may be used. Fibrolane (Great Bretain) and Merineva (Italy) are made by dissolving casein in sodium hydroxide, and then by extrusion into an acid/saltbath. The fibres formed in this way... 

The success of the regenerated cellulosic fibres stimulated the imagination of chemists. The obvious sequel was to produce a regenerated protein with properties resembling wool or silk. Much research and capital expenditure has been devoted to the production of lanital from milk casein, ardil from ground-nut protein, saran from soya bean, and vicara from maize. None of them proved really commercially successful and their manufacture has now virtually ceased. 

Chemists were described in the same glowing, positive terms found elsewhere in popular science in 1939 persistent, ingenious, creative, and able to identify the simplicity hidden in nature s complexity (LaFollette 1990). The articles emphasized traits like economy, frugality, and inventiveness. These man-made wool fibers were economical and cheap to produce because they used either less expensive raw materials or dairy by-products like dried casein powder. Potter praised chemists ingenuity and creativity in part six, he described how two advertising men turned inventors had developed a new rayon fabric they called Perval ,... 

Figure 4. Lanital Lady , a photograph by Fremont Davis which was supplied with Science Service Fabrics for the Future newspaper series, 1939. The caption explained that various steps in the production of lanital - the synthetic wool - have been used to create the lady. The doll s head was wool made from cow s milk the hands held bottles of raw casein and milk (SIA RU7091, Box 408, Folder 23). Courtesy of Smithsonian Institution Archives.

Soy protein was one of a number of proteins that were used to produce reg protein textile fibers in the late 1930s and 1940s. The discovery of regenerated protein fibers from casein is attributed to Todtenhaupt in 1904, but it was Parretti, who in 1935 successfully developed, patented, and produced a textile fiber with wool-like properties from soy protein. In the United States, soy protein textiles and felt materials were explored as replacements for wool, felt, and fur (Hartsuch, 1950 MoncriefF, 1975). In 1939, the Japanese reportedly produced about 450,000 kg (1 million lb) of soy protein fiber (Conner, 1989). The first U.S. patents for soy fibers were granted to T. Kajita and R. Inoue in 1940 (Kajita Inoue, 1940). 

Soy fibers were white to tan in color and had warm soft feel, natural crimp, and high resilience (Hartsuch, 1950). Soy protein fibers had more elongation and 80% of wool s dry strength (Boyer, 1940). These textile efforts, however, were not as successful as those made with casein fibers and failed, largely because soy protein fibers had... 

Early soy protein fibers resembled casein fibers, and later soy protein fibers even resembled rayon. The original intent of producing soy protein fibers was to compete with wool and silk (Moncrieff, 1975). The advantage of SPI over other protein sources was its relatively low price and high protein content. Soy protein fiber had one serious problem that was never solved its low tenacity, particularly when wet. Compared with wool, soy protein fiber was 45% weaker when dry and 75% weaker when wet. Because of its low tenacity, the best application for the fiber was in blends with other fibers such as wool, rayon, nylon, and cotton (Johnson Myers, 1995). 

Hysteresis phenomena in the water sorption by high polymers [125] and by other proteins such as wool fiber [125] and casein [126] have also been described. Smith [125] suggests that hysteresis is a result of differences in the ratio of bound to free water in the substrate, with a larger amount of bound water present on desorption than on absorption. 

Another important branch of the Italian chemical industry was that of fibres, such as artificial silk derived from cellulose and a casein-based fibre called Lanital. Their dynamic development partially replaced the traditional textiles as a leading export industry, while artificial fibres also replaced significantly cotton, wool and jute imports. More than 80 per cent of the overall output was produced by SNIA Viscosa and CISA Viscosa, two associated firms dominated by the same network of interlinked... 

This field should be as important to art and conservation as natural resins and waxes. It includes such diverse materials as gelatin, egg white, egg yolk, casein, and vegetable proteins. In practical terms, this field covers quite a range of very different substances, including adhesives, binding media, horn, ivory, tortoise shell, wool, silk, etc. However, as J. Mills and R. White state. 

One can argue that, for example, hydroxyproline is quite noticeable in collagen (12.8%) and completely absent in keratin (wool) or fibrin (sUk) or could be found in gelatin (7.4%) but has a zero content in egg white, egg yolk, and casein — materials very often used as adhesives and binding media. 

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