High temperature vulcanization of elastomers: 3. Network structure of efficiently vulcanized natural rubber mixes

Loo, C.T.

doi:10.1016/0032-3861(74)90025-1

Cited by 23 publications

(21 citation statements)

References 19 publications

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“…This effect was studied in several works on materials as BR, EPDM, NBR, NR and SBR [9,[13][14][15], and some of these works were addressed to obtain the activation energy associated with the vulcanization process.…”

Section: Introductionmentioning

confidence: 99%

Influence of vulcanization temperature on the cure kinetics and on the microstructural properties in natural rubber/styrene-butadiene rubber blends prepared by solution mixing

Mansilla

Marzocca

Macchi

et al. 2015

European Polymer Journal

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Section: Introductionmentioning

confidence: 99%

Influence of vulcanization temperature on the cure kinetics and on the microstructural properties in natural rubber/styrene-butadiene rubber blends prepared by solution mixing

Mansilla

Marzocca

Macchi

et al. 2015

European Polymer Journal

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“…Traducción libre de los autores a partir de la figura original Independientemente del tipo de formulación empleada, la temperatura establecida durante el proceso y el tiempo de vulcanización pueden modificar la estructura entrecruzada, ya que los enlaces polisulfídicos poseen baja resistencia térmica, mientras que los enlaces monosulfídicos poseen una mayor estabilidad térmica (Mukhopadhyay et al, 1978). Si se emplea un sistema convencional en una formulación de caucho natural se espera que durante el proceso de vulcanización el compuesto presente reversión, debido a la degradación de los enlaces polisulfídicos y la formación de enlaces monosulfídicos cíclicos, es decir, se disminuye la red entrecruzada y por lo tanto disminuye la densidad de entrecruzamiento del compuesto (Akiba and Hashim, 1997;Loo, 1974).…”

Section: Química De Vulcanizaciónunclassified

“…Figura 6. Efecto de la temperatura en la densidad de entrecruzamiento de un compuesto de caucho elaborado con un SV convencional con azufre (Loo, 1974). Traducción libre de los autores a partir de la figura original…”

Section: Química De Vulcanizaciónunclassified

Efecto del sistema de vulcanización en la red entrecruzada y en la reacción química de vulcanización del caucho natural

Yepes

Restrepo

Vásquez

et al. 2018

reveia

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RESUMENSe presenta una revisión sobre el efecto del sistema de vulcanización en la estructura formada durante la reacción de vulcanización, en la cinética de la reacción y en las propiedades de formulaciones que emplean caucho natural. Se encontró que aún existen aspectos por investigar dada la variedad de acelerantes, proporciones acelerante/azufre, tipos de caucho natural y formulaciones que emplean caucho natural. La mayor parte de la literatura evalúa la reacción de vulcanización mediante reometría de vulcanización y calorimetría diferencial de barrido (DSC), pero estas técnicas no permiten identificar el tipo de enlaces sulfídicos formados ni la densidad de enlaces entrecruzados. La temática es de gran interés científico e industrial pues el caucho natural es el caucho más comercializado a nivel mundial, y su vulcanización se realiza en la gran mayoría de las formulaciones empleando azufre como agente entrecruzante. PALABRAS CLAVES:Caucho natural, sistema de vulcanización, reacción de vulcanización, red entrecruzada, agente vulcanizante, acelerantes Revista EIA, ISSN 1794-1237 / Año XIV / Volumen 14 / Edición N.28 / Julio-Diciembre 2017 / pp. 99-115 Publicación semestral de carácter técnico-científico / Universidad EIA, Envigado (Colombia)

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“…It has been observed that (see Loo [19] and [20]) the monosulfidic crosslinks are very stable even at 200 • C, which is attributed to the strong C-S bond compared to the much weaker S-S bond found in disulfidic and polysulfidic crosslinks. The vulcanization of rubber is usually carried out at about 140 • C. Therefore, in normal processing range, not all the formed crosslinks degrade.…”

Section: Introductionmentioning

confidence: 99%

“…. , 8 can degrade (see Loo [19] and [20]) to its respective dead ends. the reasons discussed in the pages 625-627 of Ghosh et al [15], the rate at which desulfurization occurs must be independent of the number of S −S bonds, and hence, the reactions (5.34k) through (5.34q) have the same rate constant.…”

Section: Introductionmentioning

confidence: 99%

A thermodynamical framework for chemically reacting systems

Kannan

Rajagopal

2010

Z. Angew. Math. Phys.

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In this paper, we develop a thermodynamic framework that is capable of describing the response of viscoelastic materials that are undergoing chemical reactions that takes into account stoichiometry. Of course, as a special sub-case, we can also describe the response of elastic materials that undergo chemical reactions. The study generalizes the framework developed by Rajagopal and co-workers to study the response of a disparate class of bodies undergoing entropy producing processes. One of the quintessential feature of this framework is that the second law of thermodynamics is formulated by introducing Gibbs' potential, which is the natural way to study problems involving chemical reactions. The Gibbs potential-based formulation also naturally leads to implicit constitutive equations for the stress tensor. Another feature of the framework is that the constraints due to stoichiometry can also be taken into account in a consistent manner. The assumption of maximization of the rate of entropy production due to dissipation, heat conduction, and chemical reactions is invoked to determine an equation for the evolution of the natural configuration κ p(t) (B), the heat flux vector and a novel set of equations for the evolution of the concentration of the chemical constituents. To determine the efficacy of the framework with regard to chemical reactions, those occurring during vulcanization, a challenging set of chemical reactions, are chosen. More than one type of reaction mechanism is considered and the theoretically predicted distribution of mono, di and polysulfidic cross-links agree reasonably well with available experimental data. Mathematics Subject Classification (2000). Primary 74F25 · 74F05.

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High temperature vulcanization of elastomers: 3. Network structure of efficiently vulcanized natural rubber mixes

Cited by 23 publications

References 19 publications

Influence of vulcanization temperature on the cure kinetics and on the microstructural properties in natural rubber/styrene-butadiene rubber blends prepared by solution mixing

Influence of vulcanization temperature on the cure kinetics and on the microstructural properties in natural rubber/styrene-butadiene rubber blends prepared by solution mixing

Efecto del sistema de vulcanización en la red entrecruzada y en la reacción química de vulcanización del caucho natural

A thermodynamical framework for chemically reacting systems

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