Synthetic rubber, classification

The serious development of synthetic rubbers commenced in the late 1930s and early 194(ls. accelerated by a cutoff of supplies of natural rubber because of political turmoil and war. Synlhetic rubbers fall into two major classifications (1) general-purpose rubbers, the major volume of which is nevertheless used for tire production and (2) specialty rubbers that essentially find little use in (ires, hut that are important for a number of other categories. Synthetic rubbers have not replaced natural rubber for numerous uses. For large, heavy-duty truck and bus tires, natural rubber tends to mn considerably cooler and wears better than a blend of natural and synthetic rubbers. On the other hand, a tire (read made of a blend of styrene-butadiene (SBR) and butadiene rubber (polybutadiene) wears longer than natural rubber in conventional automobile, usage, where lower temperatures can be maintained. 

On 19 March and 24 April 1941, the TEA [Technische Ausschufi der I.G. Farbenindustrie AG Technical Committee] decided upon the details of production in Auschwitz. Two factories were to be created, one for synthetic rubber (Buna IV) and one for acetic acid. [...] Investment in Auschwitz initially amounted to over 500,000,000 Reichsmarks, but, in the end, to over 700,000,000 Reichsmarks. Approximately 170 sub-contractors were assigned to the work. The factory was erected streets were built barracks for the inmates were constructed barbed wire was used for factory fencing when the city of Auschwitz was finally completely filled with I.G. personnel, two company towns were built. To ensure that I.G. Auschwitz received all the needed materials, [I.Q. official] Krauch ordered Emergency Classification I for all materials required for the manufacture of Buna. In the meantime, and in addition, I.G. Auschwitz assured itself of its own coal supplies, from the Fiirsten mine and Janina mine. Both mines were operated using Jews. ... 

Industry 2823 entitled Plastics Materials and Elastomers, except Synthetic Rubber is in industry group 282, entitled Industrial Organic Chemicals. This group is a part of major group 28, Chemicals and Allied Products. It is in part 1, The Manufacturing Industry Section of the Standard Industrial Classification Code (7). 

Establishments primarily engaged in manufacturing synthetic rubber by polymerization or copolymerization. An elastomer for the purpose of this classification is a rubber-like material capable of vulcanization, such as copolymers of butadiene and styrene, or butadiene and acrylonitrile, polybutadienes, chloroprene rubbers, and isobutylene-isoprene copolymers. Butadiene copolymers containing less than 50 percent butadiene are classified in Industry 2821. Natural chlorinated rubbers and cyclized rubbers are considered as semifinished products and are classified in Industry 3069. 

Isocyanates, n.o.s. or Isocyanate Solution, n.o.s. These include a number of chemical products used in the manufacture of plastic foams, synthetic rubber, etc. Some are sufficiently toxic or lachrymatory to need classification as toxic substances, particularly isocyanates in pure form. Others may need to be classified as flammable liquids, depending on their characteristics, and a number may not be subject to these Instructions. ICAO A2... 

TABLE 9.14 ASTM and IISRP Classification of Oils for Oil-Extended Elastomers (The Synthetic Rubber Manual, 1999)... 

Synonyms Benzene, ethenyi-, polymer with 1,3-butadiene B/S Butadi-ene/styrene copolymer 1,3-Butadiene/styrene copolymer Butadiene/ styrene polymer 1,3-Butadiene/styrene polymer Butadiene/styrene resin 1,3-Butadiene/styrene resin Butadiene/styrene rubber Ethenylbenzene polymer with 1,3-butadiene Polybutadiene/polysty-rene copolymer Poly (styrene-co-butadiene) S/B SBR Styrene/butadiene Styrene/butadiene copolymer Styrene/1,3-butadiene copolymer Styrene polymer with 1,3 butadiene Classification Polymer synthetic rubber Formula pCH2CH(C6H5)],(CH2CH=CHCH2),... 

Classification Polymer Definition Synthetic rubber made by random polymerization of acrylonitrile and butadiene by free-radical catalysis Empirical (C7HsN)x... 

Classification Polymer synthetic rubber Formula pCH2CH(C6H5)]x(CH2CH=CHCH2)y Properties Amorphous solid odorless insol. in water and most org. soivs. dens. 0.965 Toxicology Eye irritant may cause irritation questionable carcinogen tumorigen TSCA listed... 

In addition to natural rubber, today many synthetic rubbers are commercially available. Although there are several ways to classify these rubbers, the American Society for Testing and Materials (ASTM) Standard D1418-85 gives the classification and designation of rubbers based on their chemical composition. Therefore, in this chapter, the classification and naming of rubbers are based on this standard. For convenience, the nomenclature is reproduced in Table 1, extracted from the standard. 

The Science of Rubber Compounding TABLE III Classification of Synthetic Rubbers by IISRP... 

Table 4.3 Classification of emulsion elastomers by the International Institute of Synthetic Rubber Producers [3],...

Classification of Polymers Free-Radical Chain-Growth Polymerization Cationic Chain-Growth Polymerization Anionic Chain-Growth Polymerization Stereoregular Polymers Ziegler-Natta Polymerization A WORD ABOUT... Polyacetylene and Conducting Polymers Diene Polymers Natural and Synthetic Rubber Copolymers... 

A somewhat crude though convenient classification can be made on the basis of the principal ingredients, thus. (1) Portland cement, (2> high alumina cemenl. (3) sodium silicate. (4 magnesium oxychloride plus copper powder, (5) litharge or red lead plus glycerol. (6) rubber latex, and (7) synthetic resins. Supplementary materials to be considered are asbestos, white lead, plaster of Paris, sulfur, graphile, sand, pilch, tar, rosin, and boiled linseed oil. 

The most fundamental classification of polymers is whether they are naturally occurring or synthetic. Common natural polymers (often referred to as biopolymers) include macromolecules such as polysaccharides e.g., starches, sugars, cellulose, gums, etc.), proteins e.g., enzymes), fibers e.g., wool, silk, cotton), polyisoprenes e.g., natural rubber), and nucleic acids e.g., RNA, DNA). The synthesis of biodegradable polymers from natural biopolymer sources is an area of increasing interest, due to dwindling world petroleum supplies and disposal concerns. 

The U.S. Customs laboratories encounter a wide variety of analytical problems. For example, when a sample of imported rubber arrives in one of the U.S. Customs laboratories, a series of determinations must be made 1) is it a rubber by definition of the tariff, 2) is it entirely natural rubber, or a synthetic blend, 3) what is its composition by weight. The answers to these questions determine the tariff classification and the applicable rate of duty. 

Classification Thermoplastic elastomer Definition Polymer of isoprene major component of natural rubber, also made synthetically avail, in range of std., oil-extended and carbon bik.-filled grades props, vary with catalysts used in mfg. (lithium, titanium)... 

It is difficult to make a distinct classification of biodegradable polymers. Many authors have classified them according to their origin as natural or synthetic polymers. Both of these are subdivided into different classes based on the main linkages present in their structure. Thus completely biodegradable natural polymer subclasses include polysaccharides, polypeptides, polyesters, lipids, natural rubber and natural composites (wood). Partially biodegradable synthetic polymer subclasses include polyesters, polyur eas, polyurethanes, polyamides, poly( vinyl alcohol) and poly (ethylene glycol). 

The synthetic man-made fibers include the polyamides (nylon), polyesters, acrylics, polyolefins, vinyls, and elastomeric fibers, while the regenerated fibers include rayon, the cellulose acetates, the regenerated proteins, glass and rubber fibers. Figure 1-1 shows a classification chart for the major fibers. 

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