Styrene-butadiene rubber cure properties

Styrene-butadiene rubber (SBR) is a random polymer made from butadiene and styrene monomers. It possesses good mechanical property, processing behavior, and can be used like natural rubber. Moreover, some properties such as wear and heat resistance, aging, and curing property are even better than in natural rubber. Styrene-butadiene rubber was the first major synthetic rubber to be produced commercially. Now it has become the most common rubber with the largest production and consumption in the synthetic rubber industry. It can be widely used in tire, adhesive tape, cables, medical instruments, and all kinds of rubberware. 

Ismail, H. Suzaimah, S. Hairunezam, H.M. Curing characteristics, mechanical properties and oil resistance of styrene butadiene rubber/epoxidized natural rubber blends. J. Elastomers Plast. 2002, 34 (2), 119-130. 

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). 

Like natural rubber, styrene butadiene rubber (SBR) can be blended in all proportions with bromobutyl rubber. However, SBR is less desirable for blending than natural rubber due to its low tack and green strength properties. In addition, heat, flex fatigue resistance, and weathering resistance are poorer with SBR blends than with natural rubber blends. Suggested cure systems are the same as those for bromobutyl/natural rubber blends. 

M.A. Mansilla, A.J. Marzocca, C. Macchi, A. Somoza, Influence of vulcanization temperature on the cure kinetics and on the microstructural properties in natural rub-ber/styrene-butadiene rubber blends prepared by solution mixing, European Polymer Journal, ISSN 0014-3057 69 (August 2015) 50-61. http //dx.doi.0rg/lO.lOl6/j. eurpolymj. 2015.05.025. 

The thermal stability of NR and carboxylated styrene butadiene rubber (XSBR) lattices and their blends were studied by thermogravimetric methods by Stephen et The thermal degradation and ageing properties of these individual lattices and their blends were investigated with special reference to blend ratio and vulcanization techniques. As already described, as the XSBR content in the blends increased, their thermal stability was also found to increase. Among sulphur and radiation-vulcanized samples, radiation cured possessed higher thermal stability due to the higher thermal stability of carbon carbon crosslinks. 

Addition of curing agent DL-268 to a natural rubber styrene butadiene rubber blend was investigated. Reversion and thermooxidatively aged physical properties... 

Studies on the vulcanisation of a black and oil filled styrene-butadiene rubber compound accelerated by a number of different sulphenamide and sulphenimide compounds were made using a conventional curemeter operated to normal ASTM standards. The vulcanisation reactions were also studied using different modelling software, CODESSA software for deriving quantitative structure-property relationships and MOPAC software for semiempirical molecular orbital calculations which together yielded excellent correlation to onset of cure and maximum cure... 

The cure and tensile properties of sulphur vulcanised styrene-butadiene rubber filled with a conventional furnace black or a fluorinated black have been determined. Compositions with the fluorinated black and normal curative levels exhibit retarded cure compared to corresponding ones with the furnace black. This is due to a reaction between the sulphenatnide accelerator and the fluorinated black. Notwithstanding, a fluoro-filled composition with no curatives substantially crosslinks when moulded at 150 deg.C. Thus, fluoro-black filled specimens have competing effects toward crosslinking. On the one hand, crosslinking is inhibited by reaction with the accelerator, while on the other, the fluoro-black itself can cause crosslinking. 2 refs. 

Zhang et al. [63] prepared styrene-butadiene nanocomposites by dispersing an aqueous dispersion of montmoril-lonite and latex and flocculating the dispersion with acid. The performance of the rubber nanocomposites were compared with clay, carbon black, and silica rubber composites prepared by standard compotmding methods. The montmoriUonite loadings for the rubber nanocomposite were up to 60 phr. The morphology of the rubber nanocomposites by transmission electron microscopy appears to indicate intercalated structures. The mechanical properties of the rubber nanocomposites were superior to all of the other additives up to about 30 phr. However, rebound resistance was inferior to all of the additives except sUica. The state of cure was not evaluated. 

Rubber products such as tyres, belts and hose rely on reinforcement by textiles to achieve the required physical properties. To effect reinforcement, textile and rubber must be adequately bonded together, and to promote adhesion, there is a range of treatments to suit most fibre-rubber systems. The adhesion-promoting material (dip) is usually a terpolymer latex of butadiene-styrene-vinyl pyridine (or a blend of SBR and vinyl pyridine), which bonds well to the fibres, together with a resorcinol formaldehyde precondensate, which, on curing, bonds well to mbber a three-dimensional resin network is formed. 

Plasticizers These are required to reduce the inherent brittleness of poly(alkyl-2-cyanoacrylates). This can be achieved by using non-copolymerizing plasticizers such as esters or higher alkyl cyanoacrylates, which copolymerize with the basic adhesive monomer. Toughness properties can be improved by the inclusion of rubber toughening materials such as ABS (acrylonitrile-butadiene-styrene) or MBS (methacrylate-butadiene-styrene) copolymers. Whichever approach is adopted, toughness is only achieved at the expense of reduced cure speed. 

The butadiene-styrene rubber (SBR), or butadiene-acrylonitrile rubber (NBR) and elastomeric graft copolymers were found particularly valuable for impact modification of PP. The PP alloys (with 5-20 wt.% of an elastomer) were reported to have advantageous properties for blow molding of bottles free from brittleness and stress cracking. Blends with natural rubber (NR) require sulfur-curing [4]. Blending with NBR dramatically increased the modulus, but the material was brittle [5]. 

Following World War II the focus on SBR turned to development of specific products demonstrating improvement in selected properties over natural rubber as well as the original SBR. The first such development was the emulsion polymerization of styrene and butadiene at low temperature in the presence of a redox catalyst system. The product from this type of process represented a marked improvement over natural rubber in tread stocks for passenger car tires. Subsequently, application of or-ganolithium catalysis permitted development of solution-polymerized SBRs that offered improvements over emulsion SBR in curing rate... 

---