Sulfur Vulcanization of Simple Model Olefins, Part IV: Vulcanizations of 2,3-Dimethyl-2-Butene with TMTD and Activated Zinc Dithiocarbamate/Xanthate Accelerators at Different Temperatures

Versloot, P.; Haasnoot, Jaap G.; Reedijk, J.; Duin, Martin van; Put, J.

doi:10.5254/1.3538757

Cited by 19 publications

(17 citation statements)

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“…64 Various structures formed in sulfur vulcanized natural rubber is shown in Scheme 12. [70][71][72] The chemical probe work has allowed characterization and quantification of the number of mono, di and poly sulphidic crosslinks. -Generalized structures in sulfur vulcanized natural rubber.…”

Section: Accelerated Sulfur Vulcanizationmentioning

confidence: 99%

Recent Developments in Crosslinking of Elastomers

Aprem

Joseph²,

Thomas

2005

Rubber Chemistry and Technology

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The recent developments in the vulcanization of elastomers, major types of crosslinking, and mechanism of crosslinking have been reviewed. Attention has been made to sum up the accelerated vulcanization. Possible mechanisms by which the reaction is taking place are discussed. The role of accelerators, activators, and fillers has been described. The different types of crosslinks and importance of each type on the specific properties of the resulting vulcanizates, etc., are discussed. Various aspects of vulcanization like model compound vulcanization, nitrosamine generation, etc., are discussed. The importance of binary accelerators and possible mechanism of their action have been mentioned. The method of double network formation, which is useful for the improvement in properties, is also described. The different methods for characterization of networks and different methods for estimating crosslink densities are also explained.

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Section: Accelerated Sulfur Vulcanizationmentioning

confidence: 99%

Recent Developments in Crosslinking of Elastomers

Aprem

Joseph²,

Thomas

2005

Rubber Chemistry and Technology

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“…22,23,49 Weak resonances in the NMR at 0.98 -0.99 and 1.33-1.34 ppm show the formation of trace amounts of alkyl alkenyl and bis(alkyl) sulfides. As reported earlier, 22,29,33 HPLC analysis showed that no pendant groups, which are readily detected in TMTD accelerated systems, 16,22,24,49 were observed at any stage in the reaction. The Zn 2 (dmtc) 4 The loss for complete conversion to ZnS is 68.25%.…”

Section: Effect Of Water On Vulcanization Of Tme/zn 2 (Dmtc) 4 /Sulfurmentioning

confidence: 63%

“…Tagged TMTD and Zn 2 (dmtc) 4 exchange at elevated temperatures, 14 which is under conditions where tetramethylthiuram polysulfides (TMTPs) can form. [2][3][4]15,16 McCleverty et al 17 also reported ligand exchange at elevated temperatures. Recent evidence for sulfur-rich zinc(II) complexes was demonstrated in theoretical density functional calculations, where it was also shown that the addition of further sulfur atoms to the zinc dithiocarbamate chelate ring is energetically more favorable than insertion of the first sulfur.…”

Section: Introductionmentioning

confidence: 99%

Effect of water and hydrogen sulfide in zinc dimethyldithiocarbamate accelerated sulfur vulcanization

Shumane

Gradwell

McGill

2002

J of Applied Polymer Sci

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Rubber and the model compound 2,3-dimethyl-2-butene (TME) are vulcanized with zinc dimethyldithiocarbamate [Zn 2 (dmtc) 4 ] accelerated sulfur formulations. When heated in dry nitrogen, Zn 2 (dmtc) 4 is stable at vulcanization temperatures. However, it shows a mass increase when heated in moist nitrogen, indicating strong coordination with water; in a nitrogen/H 2 S atmosphere rapid degradation to dimethyldithiocarbamic acid (Hdmtc) and ZnS occurs. Model compound studies show that crosslinked sulfides are essentially bis(alkenyl) and confirm the absence of accelerator terminated pendant groups in the vulcanizates, while the ease with which rubber vulcanizates crystallize on cooling in a density column also suggests that pendant groups are largely absent. However, the rates of crystallization, measured as the time for the crystallization process to go to 50% completion, are slower in lightly crosslinked gels than in peroxide cures of similar crosslink density, particularly in the vulcanizates cured in a vacuum; this is interpreted as an indication that some residual pendant groups are present in Zn 2 (dmtc) 4 vulcanizates. Water promotes the rate of crosslink formation in both rubber and TME systems, and it is suggested that the strong coordination of water with zinc in Zn 2 (dmtc) 4 promotes its reactivity. The H 2 S liberated in the vulcanization process promotes decomposition of Zn 2 (dmtc) 4 to Hdmtc, and this reaction makes an important contribution to the amount of Hdmtc that is formed in situ. The importance of Hdmtc as an accelerator and its role in providing alternative routes to crosslink formation in Zn 2 (dmtc) 4 accelerated sulfur vulcanization are discussed. It is suggested that water, which is liberated when Hdmtc reacts with ZnO to form Zn 2 (dmtc) 4 , activates newly formed Zn 2 (dmtc) 4 molecules; and this accounts for the beneficial influence of ZnO in Zn 2 (dmtc) 4 formulations.

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“…A 1 : 1 mixture of a zinc(II) bis-(isopropylxanthate) [Zn(ipxt) 2 ] and bis-(pentamethylene dithiocarbamato)piperidine Zn(II) [Zn(pmtc) 2 •(pip)] accelerator system can vulcanize rubber at room temperature. 8 This article presents the results of a study on the use of xanthate accelerators for vulcanization of NR at various temperatures and the effect of the temperature of curing on the mechanical properties of the vulcanizates.…”

Section: Introductionmentioning

confidence: 99%

Xanthate accelerators for low temperature curing of natural rubber

Palaty

Joseph

2000

J. Appl. Polym. Sci.

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Zinc salts of ethyl, isopropyl, and butyl xanthates were prepared in the laboratory. They were purified by reprecipitation and were characterized by IR, NMR, and thermogravimetric analysis techniques. The melting points were also determined. The rubber compounds with different xanthate accelerators were cured at temperatures from 30 to 150°C. The sheets were molded and properties such as tensile strength, tear strength, crosslink density, elongation at break, and modulus at 300% elongation were evaluated. The properties showed that all three xanthate accelerators are effective for room temperature curing.

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Sulfur Vulcanization of Simple Model Olefins, Part IV: Vulcanizations of 2,3-Dimethyl-2-Butene with TMTD and Activated Zinc Dithiocarbamate/Xanthate Accelerators at Different Temperatures

Cited by 19 publications

References 0 publications

Recent Developments in Crosslinking of Elastomers

Recent Developments in Crosslinking of Elastomers

Effect of water and hydrogen sulfide in zinc dimethyldithiocarbamate accelerated sulfur vulcanization

Xanthate accelerators for low temperature curing of natural rubber

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