TESPT tetrasulfane

In silica reinforcement systems containing TESPT, Wolff has suggested that the reaction is similar when the TESPT/silica intermediate is present instead of sulfur, in which case the crosslinking agent is the polysulfidic sulfur chain. Wolff showed that mercaptobenzothiazyl disulfide (MBTS) reacts with the tetrasulfane group, thus forming 2 mol of the polysulfide ... 

As reviewed earlier, a semi-EV system is a compromise designed to produce, in structural terms, a vulcanizate containing a balance of monosulfidic and polysulfidic crosslinks at a defined optimum cure state. If polysulfidic crosslinks are to persist over extended periods, new ones must be created to replace those lost through reversion. With use of normal accelerations systems, there is limited opportunity for such events. Maintenance of a polysulfidic network through the curing process thus dictates utilization of a dual-cure system both of which are independent of each other. This is the principle of the equilibrium cure (EC) system. Here, bis(3-triethoxysilylpropyl)tetrasulfane (TESPT) is added as a slow sulfur donor [38] (Fig. 7). 

Combining silanes with silica led to high-performing silica-filled rubber compounds. Organofunctional silanes with polysulfane groups such as bis-(3-(triethoxysilyl)propyl)tetrasulfane (TESPT) and bis-(3-(triethoxysilyl)propyl)disulfane (TESPD) (Fig. 12) are utilized to improve dispersability of silica in the rubber matrix. 

OC2Hs)3Si, S2, ., i(OC2H5)3 Fig. 12. Tetrasulfane TESPT (above) and disulfane TESPD (below) silanes used in tire compounds. 

The curing and dynamic properties of precipitated nano-silica on NR without and with the sulfur addition (NR with S), synthetic polyisoprene (IR), polybutadiene (BR) and SBR was investigated. Silica was treated with bis(3-triethoxysilylpropyl)tetrasulfane (TESPT) to form bonds at interfaces. Cure, Mooney viscosity, glass transition temperature, bound rubber, crosslink density and DMA were measured. The properties of silica-filled SBR and BR correlated with highest rolling resistance and SBR-silica correlated with best skid resistance. A Payne effect was observed in the loss modulus under some experimental conditions. In addition to possible filler de-agglomeration and network disruption, the nanoscale of the filler may have further contributed to the non-linear response typified by the Payne effect. ... 

Manchado et al. [127] described the synthesis of layered sUicate/natural rubber nanocomposites by mechanical and solution mixing. It was found that the filler and the polymer show good compatibility by solution blending. Addition of a coupling agent, namely bis(triethoxysilylpropyl)tetrasulfane (TESPT), could improve the adhesion between the filler and elastomer. 

H. Luginsland, Reactivity of the sulfur functions of the disulfane silane TESPD and the tetrasulfane silane TESPT , Degussa-Hiills, ACS Rubber Division Meeting, Chicago, IE, April (1999)... 

Bis(3-triethoxysilylpropyl)tetrasulfane (TESPT) note that TESPT is in fact a mixture of different polysulfane with an average S chains of four )... 

Vulcanization (Figure 6.5) the tetrasulfane group (with TESPT silan-ated silica) is broken and forms rubber-filler covalent bonds with the... 

R-F resorcinol-formaldehyde R-H resorcinol-hexamethylenetetramine S-R-H silica-resorcinol-hexamethylenetetramine TESPT bis(3-triethoxysilylpropyl)tetrasulfane. 

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