Styrene-butadiene rubber types

Plastics, such as PE, PP, polystyrene (PS), polyester, and nylon, etc., and elastomers such as natural rubber, EPDM, butyl rubber, NR, and styrene butadiene rubber (SBR), etc., are usually used as blend components in making thermoplastic elastomers. Such blends have certain advantages over the other type of TPEs. The desired properties are achieved by suitable elasto-mers/plastic selection and their proportion in the blend. 

Antiozonant additives are employed with unsaturated rubbers such as natural rubber, nitrile rubber, styrene-butadiene rubber, etc., to minimise the atmospheric ozone degradation reaction. Common antiozonant types include the parapheny-lene diamines such as N-(l,3-dimethylbutyl)-AT-phenyl-p-phenylene diamine (6PPD) and N-isopropyl-N7 phenyl-p-phenylene diamine (IPPD). Both these antioxidants can be identified and quantified using GC- or LC-based techniques. 

Plant 000033 produces three types of emulsion crumb rubber in varying quantities. Styrene butadiene rubber (SBR) forms the bulk of production, at nearly 3.7 X lO kkg/year (8.2 X lO lb/year), with nitrile butadiene rubber (NBR) and polybutadiene rubber (PBR) making up the remainder of production [4.5 x 10 kkg/year (1.0 x lO lb/year) and... 

Latexes are usually copolymer systems of two or more monomers, and their total solids content, including polymers, emulsifiers, stabilizers etc. is 40-50% by mass. Most commercially available polymer latexes are based on elastomeric and thermoplastic polymers which form continuous polymer films when dried [88]. The major types of latexes include styrene-butadiene rubber (SBR), ethylene vinyl acetate (EVA), polyacrylic ester (PAE) and epoxy resin (EP) which are available both as emulsions and redispersible powders. They are widely used for bridge deck overlays and patching, as adhesives, and integral waterproofers. A brief description of the main types in current use is as follows [87]. 

Order-disorder transitions and spinodals were computed for linear multi block copolymers with differing sequence distributions by Fredrickson et al. (1992). This type of copolymer includes polyurethanes, styrene-butadiene rubber, high impact polystyrene (HIPS) and acrylonitrile-butadiene-styrene (ABS) block copolymers. Thus the theory is applicable to a broad range of industrial thermoplastic elastomers and polyurethanes. The parameter... 

Type 104 oils are subclassified into types 104A and 104B for styrene-butadiene rubber viscosity-gravity constant (VGC) greater than 0.820 (ASTM D 2501). and are naphthenic Type 104B oils have a VGC of 0.820 max., and are paraffinic. See aromatic, naphthene, paraffin. 

Since compounds of the type XVII have shown comparable activity in a number of systems including cis-polybutadiene, styrene-butadiene rubber, and ethylene-propylene rubber, they have some commercial promise, and development work on these compounds is continuing. Nevertheless, they are not completely nondiscoloring, and in certain applications, particularly carboxylated styrene-butadiene latex films, yellow discoloration caused by the antioxidant is a serious drawback. We therefore turned our attention to ortho-linked compounds derived from 2,4-dialkylphenols. 

Materials. Two types of standard tire cord obtained from Gen Corporation were used in this investigation polyester, 1300/3, and nylon 66, 1260/3. The rubber composition to which the adhesively dipped cords were bonded had the following composition in parts by weight styrene-butadiene rubber (SBR) 1502, 100 N330 carbon black, 50 zinc oxide, 5 stearic acid, 0.5 sulfur, 1.7 2-morpholinothio-benzothiazole, 2. Master batches were mixed 7 min in a 350-ml Brabender Plasticorder, and curatives were added on a cool two-roll mill. Cure characteristics at 155 °C were determined with an oscillating disc rheometer (ASTM D 2084). The time to reach 90% of the final cure state was 23 min, and the Shore A hardness of the final vulcanizate was approximately 60. 

The last two polymers in Table I are often co-polymerized with polybutadiene to form damping materials. The co-polymer of butadiene and styrene is the basis of styrene-butadiene-rubber, or SBR, which is the most commonly used type of rubber (19). One of the largest uses is in automobile tires. The co-polymer of acrylonitrile and butadiene is the basis of nitrile-butadiene-rubber, or NBR. 

The free-radical kinetics described in Chapter 6 hold for homogeneous systems. They will prevail in well-stirred bulk or solution polymerizations or in suspension polymerizations if the polymer is soluble in its monomer. Polystyrene suspension polymerization is an important commercial example of this reaction type. Suspension polymerizations of vinyl ehloride and of acrylonitrile are described by somewhat different kinetic schemes because the polymers precipitate in these cases. Emulsion polymerizations aie controlled by still different reaetion parameters because the growing macroradicals are isolated in small volume elements and because the free radieals which initiate the polymerization process are generated in the aqueous phase. The emulsion process is now used to make large tonnages of styrene-butadiene rubber (SBR), latex paints and adhesives, PVC paste polymers, and other produets. 

BR is used in nearly all parts of the tire with the exception of the inner liner it is always blended with natural rubber (NR) or styrene-butadiene rubber (SBR). Apart from the extrudability, in NR blends the Nd-BR polymers exhibit advantages in all important compound and vulcanizate properties. Also, in SBR blends Nd-BR leads to the best vulcanizate properties in comparison with all other types of BR. 

Both addition and condensation polymerization can be carried out with mixtures of two or more types of monomers present in the reaction mixture. The result is a random copolymer that incorporates both types of monomers in an irregular sequence along the chain. For example, a 1 6 molar ratio of styrene to butadiene monomers is used to make styrene-butadiene rubber (SBR) for automobile tires, and a 2 1 ratio gives a copolymer that is an ingredient in latex paints. 

S-type synthetic elastomer. See styrene-butadiene rubber. 

Free-radicals generated in many oxidation-reduction (or redox) reactions can be used to initiate chain poymerization. An advantage of this type of initiation is that, depending on the redox system used, radical production can occur at high rates at moderate (0-50°C) and even lower temperatures. Redox systems are generally used in polymerizations only at relatively low temperatures, a significant commercial example being the production of styrene-butadiene rubber by emulsion copolymerization of butadiene and styrene at 5-10°C ( cold recipe ). 

The industrial uses of tellurium are limited. In metallurgy, tellurium is used as an additive to improve alloys. The addition of tellurium improves the creep strength of tin and the mechanical properties of lead. Powdered tellurium is used as a secondary vulcanizing agent in various types of rubbers (natural rubber and styrene-butadiene rubbers) as it reduces the time of curing and endows the rubbers with increased resistance to heat and abrasion. In addition, tellurium and its compounds have been used as oxidation catalysts in organic syntheses. Due to its photoelectric properties, tellurium and its compounds are also employed in the semiconductor and electronics industry. In much smaller quantities, tellurium is used in pottery glazes. For further details, see Fishbein (1991). 

Styrene-butadiene rubber latex (SBR, GRS) and acrylonitrile-butadiene rubber latex (NBR) are two of the earliest to arrive on the market. Since then, many other types have appeared, with poly(vinyl acetate) and copolymers, acrylics (generally polymers and copolymers of the esters of acrylic acid and methacrylic acids), and carboxylic-SBR types being the major products. Since latices are aqueous emulsions, less... 

This chapter concludes with brief reference to carboxylated rubber latexes. Further information, with references, is available in a review by Blackley [27]. Carboxylated rubber latexes contain rubbery polymers which have been modified by inclusion of a small amount of a copolymerisable carboxylic-acid monomer in the emulsion polymerization system by which they were prepared. Typical carboxylic-acid monomers are acrylic acid (XI), methacrylic acid (XII) and itaconic acid (XIII). The most industrially-important rubber latexes of this type are the carboxylated styrene-butadiene rubber latexes. Also of considerable... 

Only types (l)-(4) fall within the scope of this chapter. No further reference will be made to emulsion-polymerized prolybutadiene rubbers, because they are now of little industrial significance relative to the styrene-butadiene rubbers. Poly(vinyl chloride) is discussed elsewhere in this book. Brief reference will also be made in this chapter (Section 15.5) to the production and properties of carboxylated variants of styrene-butadiene rubber latexes. It may also be noted that latexes of rubbery terpolymers of styrene, vinyl pyridine and butadiene, produced by emulsion polymerization, have long been of considerable industrial importance for the specialized application of treating textile fibres (e.g., tyre cords) in order to improve adhesion between the fibres and a matrix of vulcanized rubber in which they are subsequently to be embedded. 

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