Effects of TESPT-Silane Coupling Agent on Torque Properties and Degree of Filler Dispersion of Silica Filled Natural Rubber and Epoxidized Natural Rubbers Compounds

The effect of the addition of a bis(triethoxysilylpropyl) tetra sulphide or TESPT-silane coupling agent on torque properties and degree of filler dispersion of silica-filled compounds of natural rubber (NR), epoxidized natural rubbers with 25% mole of epoxidation (ENR 25) and epoxidized natural rubbers with 50% mole of epoxidation (ENR 50) were investigated. All the rubbers were filled by silica filler at a fixed loading (30.0 parts per hundred rubber, phr) and the TESPT was added to each silica-filled rubbers compounds at 1.0phr. It was found that TESPT affected the torque properties of all the silica-filled rubbers compounds. The TESPT decreased the minimum torque of NR system but increased the minimum torque of ENRs systems and maximum and torque differences of the all rubbers systems. The minimum torque was decreased from 0.61 to 0.53 dN.m for NR; were increased from 0.23 to 0.49 dN.m for ENR 25 and from 0.07 to 0.34 dN.m for ENR 50.It was also found that the TESPT acted as an internal plasticizer for NR which improved the degree of silica dispersion. Presumably, for the ENRs, the TESPT acted as an additional cross linker with a more pronouncedly which poorer the degree of silica dispersion.

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Effect of Epoxide Content on the Vulcanizate Structure of Silica-Filled Epoxidized Natural Rubber (ENR) Compounds

Polymers ◽

10.3390/polym13111862 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1862

Author(s):

Gyeongchan Ryu ◽

Donghyuk Kim ◽

Sanghoon Song ◽

Kiwon Hwang ◽

Byungkyu Ahn ◽

...

Keyword(s):

Natural Rubber ◽

Coupling Agent ◽

Abrasion Resistance ◽

Silane Coupling Agent ◽

Fuel Efficiency ◽

Hydroxyl Group ◽

Coupling Reactions ◽

Silane Coupling ◽

Silica Dispersion ◽

Wet Grip

The demand for truck–bus radial (TBR) tires with enhanced fuel efficiency has grown in recent years. Many studies have investigated silica-filled natural rubber (NR) compounds to address these needs. However, silica-filled compounds offer inferior abrasion resistance compared to carbon black-filled compounds. Further, the use of NR as a base rubber can hinder silanization and coupling reactions due to interference by proteins and lipids. Improved silica dispersion be achieved without the use of a silane coupling agent by introducing epoxide groups to NR, which serve as silica-affinitive functional groups. Furthermore, the coupling reaction can be promoted by facilitating chemical interaction between the hydroxyl group of silica and the added epoxide groups. Thus, this study evaluated the properties of commercialized NR, ENR-25, and ENR-50 compounds with or without an added silane coupling agent, and the filler–rubber interaction was quantitatively calculated using vulcanizate structure analysis. The increased epoxide content, when the silane coupling agent was not used, improved silica dispersion, abrasion resistance, fuel efficiency, and wet grip. Once a basic level of silica dispersion was secured by using the silane coupling agent, both the abrasion resistance and wet grip improved with increasing epoxide content. Furthermore, the silane coupling agent could be partially replaced by ENR due to the high filler–rubber interaction between the ENR and silica. Therefore, epoxidation shows potential for resolving the issues associated with poor coupling reactions and abrasion resistance in silica-filled NR compounds.

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Effect of Surface Oxidation of Carbon Black on Its Bonding with Epoxidized Natural Rubber in the Presence of Silane Coupling Agent

Rubber Chemistry and Technology ◽

10.5254/1.3538810 ◽

1999 ◽

Vol 72 (2) ◽

pp. 398-409 ◽

Cited By ~ 7

Author(s):

Ajay K. Manna ◽

P. P. De ◽

D. K. Tripathy ◽

S. K. De ◽

M. K. Chatterjee

Keyword(s):

Carbon Black ◽

Natural Rubber ◽

Coupling Agent ◽

Silane Coupling Agent ◽

Surface Oxidation ◽

Spectroscopic Studies ◽

Epoxidized Natural Rubber ◽

Silyl Ether ◽

Silane Coupling ◽

Swelling Studies

Abstract Results of bound rubber determination, Monsanto rheometry, solvent swelling studies and measurement of physical properties reveal that high temperature molding of epoxidized natural rubber (ENR) filled with intermediate super abrasion furnace (ISAF) carbon black and surface oxidized ISAF carbon black, in the presence of silane coupling agent, namely, N-(4-vinylbenzyl)-N′-[3-(trimethoxysilyl)propyl]ethane-1,2-diamine monoHCl salt, results in crosslinking of the rubber phase, even in the absence of the vulcanizing agents. Infrared spectroscopic studies show formation of silyl ether, in the case of ISAF carbon black, whereas the oxidized grade forms both silyl ether as well as silyl ester and amide linkage. Oxidation of ISAF carbon black causes an increase in the extent of coupling bond formation.

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