Animal hides

Protein-Based Adhesives. Proteia-based adhesives are aormaHy used as stmctural adhesives they are all polyamino acids that are derived from blood, fish skin, caseia [9000-71 -9] soybeans, or animal hides, bones, and connective tissue (coUagen). Setting or cross-linking methods typically used are iasolubilization by means of hydrated lime and denaturation. Denaturation methods require energy which can come from heat, pressure, or radiation, as well as chemical denaturants such as carbon disulfide [75-15-0] or thiourea [62-56-6]. Complexiag salts such as those based upon cobalt, copper, or chromium have also been used. Formaldehyde and formaldehyde donors such as h exam ethyl en etetra am in e can be used to form cross-links. Removal of water from a proteia will also often denature the material. 

Chromium is also important in converting animal hides into leather. In the tanning process, hides are treated with basic solutions of Cr(HI) salts, which causes cross-linking of collagen proteins. The hides toughen and become pliable and resistant to biological decay. 

Cellophane is, after chemical modification, obtained from the cellulose in wood, just as paper (from cellulose and lignin), cellulose fibres ( rayon ), and cellulose plastics. Leather is made from animal hides in a tanning process. 

Leather is an important material in the world economy, being used in footwear, clothing, luggage and upholstery. It is a complex substrate prepared from animal hides and skins by a long series of treatments. After the removal aU organic material and hairs the material is tanned, usually with chromium salts, which causes the protein chains to cross-link. After treating with oils or fats, to improve its handle, the leather is dyed. 

The head of a safety match consists of K chlorate 45-55, animal (hide) glue (as a binder) 9-11, sulfur or rosin 3-5, extender (starch, dextrin) 2-3, neutralizer (ZnO.or Ca carbonate) 45-55, infusorial earth 5-6 other siliceous filler 15-32%. Fractional percentages of a soluble burning rate catalyst, such as K di-chromate, also soluble dye stuffs, etc... 

Abumen - [FLAME RETARD ANTS - PHOSPHORUS FLAME RETARDANTS] (Vol 10) - [EGGS] (Vol 8) -m animal hides [LEATHER] (Vol 15)... 

Collagen - [FOOD ADDITIVES] (Vol 11) - [PROTEINS] (Vol 20) -m animal hides [LEATHER] (Vol 15) -as cell microcarrier [CELL CULTURE TECHNOLOGY] (Vol 5) -effect of copper on [MINERAL NUTRIENTS] (Vol 16) -gelatin from [GELATIN] (Vol 12) -sumres of [SUTURES] (Vol 23)... 

Lint from clothes dryers (papier-mache pulp can also be used) kitchen blender transparent or masking tape animal hide glue embroidery hoops thinly woven fabric trays slightly larger than embroidery hoop NaCIO (5% sodium hypochlorite solution bleach) 250 ml beaker red and blue litmus paper watercolor paint prepared in Activity 2.5 commercial watercolor paint paintbrushes mixing trays water containers centigram balance hot plate watch glass. 

The conversion of animal hides into leather by treatment with water-soluble plant extractives has been practiced since antiquity. This process became known as tanning and obviously involved the reaction of a naturally occurring extractive, tannin, with the protein in the hide. We now know, of course, that tannins comprise a whole spectrum of chemical compounds, but generally they are polyphenolic and polymeric. Tannins have been isolated from a wide variety of raw materials, including insect galls, fruit skins, seed hulls, leaves, bark, and heartwood. Indeed, tannins are of nearly ubiquitous occurrence in higher orders... 

Industrial workers often complain of nausea, vomiting, diarrhea, stomach pain, headache, sweating, and a metallic taste in the mouth. Depending on the metals in question, there may be blue-black lines in the gum tissues and impairment of cognitive, motor, and language skills. The expression mad as a hatter comes from the mercury poisoning prevalent in seventeenth century France among hat makers, who soaked animal hides in a solution of mercuric nitrate to soften the hair. 

---