Proteins in natural rubber

These allergy risk ingredients could include proteins in natural rubber (e.g., latex gloves) or the vulcanization accelerators used to cure or cross-link the polymer materials used in CPCs or other manufacturing process additives. The accelerators/cross-linkers are not limited to natural rubber. 

IR is used in the rubber industry instead of naturai rubber because it is more uniform and reiativeiy easier to process than the tougher naturai rubber. IR is preferred in medicai appiications because it does not contain proteins, whereas NR does. These proteins in natural rubber can cause an aiiergic reaction in some peopie, which can be dangerous. IR is thus considered safer. 

ASTM D5712 Standard Test Method for Analysis of Protein in Natural Rubber... 

Natural rubber is a polymer of isoprene- most often cis-l,4-polyiso-prene - with a molecular weight of 100,000 to 1,000,000. Typically, a few percent of other materials, such as proteins, fatty acids, resins and inorganic materials is found in natural rubber. Polyisoprene is also created synthetically, producing what is sometimes referred to as "synthetic natural rubber". Owing to the presence of a double bond in each and every repeat unit, natural rubber is sensitive to ozone cracking. Some natural rubber sources called gutta percha are composed of trans-1,4-poly isoprene, a structural isomer which has similar, but not identical properties. Natural rubber is an elastomer and a thermoplastic. However, it should be noted that as the rubber is vulcanized it will turn into a thermoset. Most rubber in everyday use is vulcanized to a point where it shares properties of both, i.e., if it is heated and cooled, it is degraded but not destroyed. 

Although helical structures dominate the structural hierarchies found in proteins, random chain structures similar to those found in natural rubber also are found in tissues. The most-studied random chain polymer found in vertebrate tissues is elastin. 

Another problem is that some persons are allergic to the proteins often found in natural rubber. This can be avoided by the use of a polyurethane condom. Unfortunately, as now made, these are more likely to tear (7-9% of the time) than the rubber latex condoms (2% of the time).65 It has been suggested that they be made of guayule rubber latex, which is free of the allergens.66 Thermoplastic elastomers, such as polystyrene-6-(ethylene-co-butene)-Apolystyr ene have been used to make gloves that are more resistant to ozone than those made of natural rubber.67 These should resist aging better than those made of natural rubber. It should be possible to mold a condom without holes from a thermoplastic rubber. 

The density of natural rubber is about 0.913 g per cc, and its bulk density is about 0.85 g per cc. The rubber hydrocarbon content of raw natural rubber is about 94%. The presence of small quantities of non-rubber constituents such as proteins, fats, fatty acids, carbohydrates, and mineral matter in natural rubber influences its physical and chemical properties. 

Macromolecules are molecules built from a large number of atoms. They can be of natural origin, like cellulose, proteins, and natural rubber, or they may be synthetically produced, like poly(ethylene), nylon, and silicones. All macromolecules consist of at least one chain of atoms bonded together and running through the whole molecule. This backbone can consist of, for example, carbon atoms, as in... 

Proteins, polysaccharides, natural rubber, and gums are all natural polymers. The repeat units in proteins are amino acids. Nucleic acids are composed of nucleotides and polysaccharides consist of sugar units. 

Polychloroprene latexes are aqueous dispersions of synthetic polychloroprene polymers with surfactants. The surfactants of choice are markedly different than the protein-based surfactants contained in natural rubber latex that is reportedly at the root of human hypoallergenic reactions associated with the use of natin-al rubber latex. 

Polymers can be divided into natural, modified, and synthetic polymers. A natural polymer refers to a polymer compound existing in nature. Cotton, silk, starch, protein, wood, natural rubber, and so forth that we usually use in clothing, food, housing, and transport are natural polymer materials. 

The history of the development of condoms precedes a review of the use of natural latex mbber condoms, with details of some of the problems encountered by users, and the subsequent development of a polyurethane condom by London International Group. The use of condoms for both pregnancy prevention and as a barrier to sexually transmitted diseases, including AIDS, is discussed, and the effectiveness of both latex and PU for this purpose. The use of polyurethane condoms as an alternative to latex by those experiencing latex sensitivity, either due to the protein in the rubber or vulcanising agents is proposed, since polyurethane has been shown to be non-allergenic. Test methods for condoms are examined, and results of in-use studies of the Avanti condom made from Duron brand PU are discussed. 3 refs. 

As it is now possible by choice of suitable conditions to prepare most compounds in this form, the colloid state should be considered as a physical state in which all substances can be made to exist. Many ma terials such as proteins, vegetable fibres, rubber, etc. are most stable or occur naturally in the colloidal slate. In the colloidal stale the properties of surface are all-important. 

In addition to plastics materials, many fibres, surface coatings and rubbers are also basically high polymers, whilst in nature itself there is an abundance of polymeric material. Proteins, cellulose, starch, lignin and natural rubber are high polymers. The detailed structures of these materials are complex and highly sophisticated in comparison the synthetic polymers produced by man are crude in the quality of their molecular architecture. 

Hamann CP Natural rubber latex protein sensitivity in review. Am J Contact Derm 4 4, 1993... 

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