The role of devulcanizing agent for mechanochemical devulcanization of styrene butadiene rubber vulcanizate

Abstract

More or less universally, bis(3-triethoxysilyl propyl) tetrasulfide (TESPT) has been used as a coupling agent during dispersion of silica filler in a virgin nonpolar rubber compound. It is for the first time that TESPT has been used as a devulcanizing agent and as-grown devulcanized rubber facilitates the silica dispersion in nonpolar rubber compound without any coupling agent. Dual functionalities of TESPT have been modeled and validated in this work. Various factors like the role of sol-gel content, inherent viscosity of sol rubber, crosslink density, and degree of devulcanization were investigated as a function of devulcanization time and amount of TESPT to optimize devulcanization time and TESPT amount. To study the silica reinforcement, revulcanization of devulcanized SBR was carried out with silica filler and the curing characteristics of the material were evaluated. From the mechanical properties and thermogravimetry analysis the optimum time for devulcanization is determined. Further, scanning electron microscopy (SEM) studies were undertaken to check the coherency and homogeneity of the material. POLYM. ENG. SCI., 58:74-85, 2018.

Manifestation of accelerator type and vulcanization system on the properties of silica‐reinforced SBR/devulcanize SBR blend vulcanizates

“…The SEM micrographs of the tensile fracture surface of silica‐reinforced SBR/DeVulcSBR blend vulcanizates containing different accelerator systems are shown in Figure (a–d). The mechanism of silica reinforcement in the presence of devulcanize rubber is reported in our previous publication . The accelerator type having almost comparable cross‐link density does not influence the morphology of the blend vulcanizates, still the SEM micrographs of the tensile fracture surface of the blend vulcanizates are analyzed to know about the phase morphological structure and homogeneity due to dispersion of silica filler into the blend vulcanizate.…”

“…DeVulcSBR is prepared from the ground styrene‐butadiene rubber (GSBR) vulcanizate using TESPT, a dual function disulfide chemical, reported earlier . Styrene‐butadiene rubber (SBR‐1502) (Synthetics and Chemicals Ltd., India), TESPT as devulcanizing agent, zinc oxide (S.D.…”

“…So handling of these disulfides and thiols is not desirable and economic for devulcanized rubber production. But TESPT containing – S – S – bonds is thought to be used as devulcanizing agent for rubber vulcanizate and subsequent study of extent of devulcanization indicates that TESPT is functioning as devulcanizing agent during the process of devulcanization and the ethoxy end group of fragmented TESPT, which are attached with devulcanized rubber, can form chemical bond with silica filler during its product application. Therefore, costlier carbon black can be replaced by comparatively low‐cost silica filler without much compensation of mechanical properties.…”

A Theoretical and Experimental Study for Screening Inhibitors for Styrene Polymerization

“…Over decades, styrene (ST) monomer has been employed to manufacture important commercial commodities such as acrylonitrile butadiene styrene (ABS), and styrene butadiene rubber (SBR) [1][2][3][4]. However, during distillation, storage, and transportation of ST, undesired polymer (UP) formation or organic peroxides fouling can presumably occur in the processing equipment, which reduces the heat transfer rate and increases the required time of cleaning [5,6].…”

Effect of Temperature on Devulcanization of Waste Sidewall Rubber by Supercritical Ethanol

“…1 Various types of devulcanizing routes have been studied so far in order to improve the quality of the recycled products, such as chemical method, mechanical process, microwave technique, ultrasonic method and microbial method. [2][3][4][5][6][7][8][9][10][11][12][13] However, some processes have weaknesses such as environmental pollution and low efficiency.…”