Resins animal

Natural resins Pine resins, sandarac, copals, mastic, dammar, amber, frankincense, benzoe, styrax, myrrh, (plant resins) shellac (animal resin) tar and pitch (from thermal treatment of plant resins or wood) Varnishes, coatings, waterproofing materials, paint binders, ingredients of cosmetic and pharmaceutical preparations... 

The following sections discuss in detail the Py-GC/MS of proteinaceous materials, oils and fats, and then briefly plant and animal resins, polysaccharide materials, and beeswax. Particular attention is given to the application of this analytical technique to characterise samples from works of art. At the end of the chapter four case studies are presented. 

Employing enolate chemistry. Ley et developed a solid-phase synthesis of bicyclo[2.2.2] octanes of type 316 based on a double Michael addition strategy. As depicted in Scheme 4.6.2, polymer-bound acrylate 313 was treated with cyclohexenone enolates derived from 314 to give 315. After reductive animation, resin-bound bicyclo[2.2.2]octanes 316 were cleaved under a set of different conditions. Aminolysis with different amines and acidolysis using TEA led to the formation of 317 and 318, whereas reduction with DIBAH gave alcohols of type 319. 

Exposure to PTFE can arise from ingestion, skin contact, or inhalation. The polymer has no irritating effect to the skin, and test animals fed with the sintered polymer have not shown adverse reactions. Dust generated by grinding the resin also has no effect on test animals. Formation of toxic products is unlikely. Only the heated polymer is a source of a possible health hazard (120). 

PVDE is a nontoxic resin and may be safely used in articles intended for repeated contact with food (190). Based on studies under controked conditions, including acute oral, systemic, subchronic, and subacute contact implantation and tissue culture tests, no adverse toxicological or biological response has been found in test animals (191,192). PVDE is acceptable for use in processing and storage areas in contact with meat or poultry products prepared under federal inspection and it complies with the 3-A sanitary standards for dairy equipment. 

Poly(ethylene oxide) resins are safely used in numerous pharmaceutical and personal-care appHcations. Poly(ethylene oxide) resins show a low order toxicity in animal studies by all routes of exposure. Because of their high molecular weight, they are poorly adsorbed from the gastrointestinal tract and completely... 

Vatty Acids andFattyAcidLsters. Sulfolane exhibits selective solvency for fatty acids and fatty acid esters which depends on the molecular weight and degree of fatty acid unsaturation (40—42). AppHcations for this process are enriching the unsaturation level in animal and vegetable fatty oHs to provide products with better properties for use in paint, synthetic resins, food products, plastics, and soaps. 

The solvent is then evaporated, and the unconverted sterol is recovered by precipitation from an appropriate solvent, eg, alcohol. The recovered sterol is reused in subsequent irradiations. The solvent is then evaporated to yield vitamin D resin. The resin is a pale yeUow-to-amber oil that flows freely when hot and becomes a brittie glass when cold the activity of commercial resin is 20 30 x 10 lU/g. The resin is formulated without further purification for use in animal feeds. Vitamin D can be crystallized to give the USP product from a mixture of hydrocarbon solvent and ahphatic nitrile, eg, benzene and acetonitrile, or from methyl formate (100,101). Chemical complexation has also been used for purification. 

Animal uses employ resin in various stabilized forms at levels of 200,000 400,000 500,000 and 1 x 10 units of per gram. Combination products containing A and D are also available, with 650,000 units of vitamin A and 325,000 units vitamin D per gram of product being the most common dosage form. 

Benzoic acid in the free state, or in the form of simple derivatives such as salts, esters, and amides, is widely distributed in nature. Gum benzoin (from styrax ben in) may contain as much as 20% benzoic acid in the free state or in combinations easily broken up by heating. Acaroid resin (from anthorrhoca haslilis) contains from 4.5 to 7%. Smaller amounts of the free acid are found in natural products including the scent glands of the beaver, the bark of the black cherry tree, cranberries, pmnes, ripe cloves, and oil of anise seed. Pern and Tolu balsams contain benzyl benzoate the latter contains free benzoic acid as well. The urine of herbivorous animals contains a small proportion of the glycine derivative of benzoic acid, hippuric acid [495-69-2] (CgH CONHCH2COOH). So-called natural benzoic acid is not known to be available as an item of commerce. 

Some skin sensitization to low molecular-weight DGEBPA resins (mol wt - 340) has been shown in animals and humans. Skin sensitization decreases with an increase in molecular weight but the presence of low molecular-weight fractions in the advanced resins may present a hazard to skin sensitization (43). 

Inhalation toxicity does not present a hazard because of low vapor pressure. DGEBPA-based resins have been reported to cause minimal eye irritation (44). Systemic toxicity has not been noted in experiments where DGEBPA-based resins have been fed to laboratory animals. Mutagenic activity has not been shown in animals, but in vitro mutagenicity tests have yielded variable results (44). 

Carcinogenicity of DGEBPA or DGEBPA-based resins, as measured by topical appHcation, has not been shown by a majority of the studies (45). Advanced DGEBPA resins exhibit low systemic toxicity either by dermal or oral routes and inhalation of these resins is unlikely because of low volatihty. The acute oral LD q in rats has been reported to be >2000 mg/kg (46). Acute dermal studies show these materials have alow potential for absorption through the skin in acutely toxic amounts. No evidence of carcinogenicity has been found in animals or humans for advanced DGEBPA resins (47,48). 

Epoxy Phenol Novolak Resins. Acute oral studies indicate low toxicity for these resins (49). Eye studies indicate only minor irritation in animals (49). The EPN resins have shown weak skin-sensitizing potential in humans. 

Resins can be divided into natural and synthetic types. Natural resins have a vegetable or animal origin. Typical examples are rosins. Synthetic resins result from controlled chemical reactions, and can be divided into two subgroups. 

The selection of mix ingredients may depend heavily on the type of adhesive applieation equipment used. The main types of equipment for plywood and LVL are roll coaters, spray systems, eurtain coaters, and foam extruders. When foam extruders are used, animal blood and surfactants are usually added to the mill mix. For other application systems, resin producers typieally supply the non-filler additives as part of the resin eomposition. 

The carbon dioxide removed in synthesis gas preparation can be reacted with ammonia, to lonn urea CO(NH2)2- This is an excellent fertilizer, highly concentrated in nitrogen (46.6%) and also useful as an additive in animal feed to provide the nitrogen for formation of meat protein. Urea is also an important source of resins and plastics by reacting it with formaldehyde from methanol. 

Uses of Urea. The major use of urea is the fertilizer field, which accounts for approximately 80% of its production (about 16.2 billion pounds were produced during 1994 in U.S.). About 10% of urea is used for the production of adhesives and plastics (urea formaldehyde and melamine formaldehyde resins). Animal feed accounts for about 5% of the urea produced. 

Phenol was originally recovered during the coking of coal, essentially being a by-product. Eventually, commercial routes were developed based on benzene (from coal or petroleum) for example, sulfonation of benzene to ben-zenesulfonic acid followed by reaction with water to phenol plus regenerated sulfuric acid. Phenol is used to make plastics (phenol-formaldehyde and epoxy resins) and textile fibers (nylon). Phenol is also used in solution as a general disinfectant for cleaning toilets, stables, floors, drains, etc. and is used both internally and externally as a disinfectant for animals. 

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