E-SBR

Fig. 12 Stress-strain curves of a 19NBR, b 34NBR, c 50NBR, d BR, and e SBR and their nanocomposites with control unmodified (NA) and modified (o-MMT) montmorillonite clays...

Tagata and Homma47 analyzed in the aforementioned manner the compositional heterogeneity of two typical commercial SBR samples, E-SBR and S-SBR, which had 23.5 and 20.0 average styrene wt.%, and were produced by an emulsion polymerization and by a solution polymerization with an organometallic catalyst, respectively. The result was that the former gave a distinctly narrower compositional distribution than the latter. GPC experiments on these samples were also carried out, which indicated that the above situation was just the opposite for the molecular-weight distributions. 

Styrene-butadiene rubber, or E-SBR as it is known in manufacturing circles, was first developed in the 1930s. Known as Buna S, the compound was prepared by I.G. Farbenindustrie in Germany. Manufacturing styrene-butadiene rubber was through an emulsion polymerization process which produced a material that had a low reaction viscosity, yet had all the attributes of natural rubber. 

Initial processes for emulsion (E-SBR) called for polymerization at 50 C However, it was found later that cold processing produced a rubber particularly good for tires. This is sometimes referred to as add... 

Fig. 3 Example of stress softening with successively increasing maximum strain for an E-SBR-sample filled with 80 phr N 339...

Fig. 21 Aggregate size distribution obtained from TEM-analysis (in-rubber state) of E-SBR-samples filled with 50 phr N330 at various mixing times, as indicated [115]...

Fig. 23 Fractal analysis according to Eq. (14) of primary carbon black aggregates (N339) prepared from E-SBR-composites with 60 phr filler (in-rubber state). Vp is evaluated from Eq. (12)...

Fig. 26 D.c.-conductivity vs carbon black volume fraction of E-SBR samples filled with various furnace blacks. The solid lines are least square fits according to Eq. (15). Experimental data are taken from [124]...

Fig. 17. Double logarithmic plot of the small strain storage modulus vs filler volume fraction for E-SBR/BR(m)-microgel composites with varying size of the BR-microgels as indicated (open symbols). The solid line represents a master curve with slope 3.5 estimated from Eq. (72) with layer thickness A=2 nm (solid symbols). Experimental data are taken from [94,95]...

Styrene-butadiene rubber could be produced by using emulsion and solution process, thus it can be divided into emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR). In this entry, we will describe their development and introduce their synthesis process, relationship between structure and property, processing property, blends, and applications. 

In addition to the polymer viscosity, polymerization temperature also plays an important role in shaping the processability. Emulsion-polymerized SBR grades produced at low polymerization temperatures have less chain branching than those produced at higher temperatures. At an equivalent viscosity, cold polymerized E-SBR is normally easier to process than hot polymerized E-SBR, and this applies particularly... 

To improve the aging property of E-SBR, Parker and Roberts used the diimide reduction method to prepare hydrogenated E-SBR. In the system containing hydrazine hydrate, oxidant, and a metal-ion catalyst, hydrogenated E-SBR with 97%o of hydrogenation could be obtained. The hydrogenated E-SBR not only exhibited excellent ozone, oxidation, and UV resistance as expected, but also showed better mechanical properties in some circumstances than unhydrogenated E-SBR. 

Moreover, E-SBR can be grafted with some polar monomers such as acrylic acid or organic chlorium to give modified E-SBR with good heat resistance and tensile strength. 

There are a large variety of E-SBR types based on the styrene content, polymerization temperature, antioxidants, oil and carbon black content. Each of these basic classifications includes a variety of SBR polymer variations with respect to Mooney viscosities, coagulation types, emulsifier type, oil levels, and carbon black types and levels. Table 2 shows the basic series of E-SBR. 

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