Alternate instrumental methods of measuring scorch and cure characteristics

Dick, John S.; Pawlowski, Henry; Scheers, E.

doi:10.1016/0142-9418(95)90615-n

Cited by 28 publications

(9 citation statements)

References 7 publications

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“…Numerous studies on the dynamic mechanical properties of various rubber vulcanisates have been reported, including the effects of types and amounts of rubber [6,7] and fillers [8][9][10] , the interaction between rubber and filler [11] , the compounding ingredients and the state-of-cure [11,12] . It is found that changes in the cross-link structures (i.e., cross-link density and cross-link type) of NR vulcanisates cause variation in glass transition temperature (T g ), elastic modulus (G 0 ) and damping factor [1] .…”

Section: Introductionmentioning

confidence: 99%

Relationship Among Thermal Ageing Degradation, Dynamic Properties, Cure Systems, and Antioxidants in Natural Rubber Vulcanisates

Pimolsiriphol

Sae‐Oui

Sirisinha

2007

Polymer-Plastics Technology and Engineering

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The present work aims to study the relationship among the thermal ageing stability, dynamic properties, cure systems, and antioxidants in natural rubber (NR) vulcanisates. Thermal degradation behavior of NR vulcanisates has been investigated and correlated to the changes in cross-link density, tensile and dynamic mechanical properties. The results obtained show that thermal ageing properties of NR vulcanisates depend strongly on cross-link density, which changes during thermal oxidative ageing or the so-called postcuring effect. In addition, the increases in ageing temperature and time lead dominantly to the postcuring and linkages scission phenomena in vulcanisates cured with CV and EV systems, respectively. With increasing ageing temperature, the tensile strength shows sharp drop at ageing temperature higher than 70 C and 100 C for the specimens cured with CV and EV systems, respectively. The sharp drop of tensile strength of vulcanisates cured with CV system is attributed to the too high cross-link density, which is caused by the postcuring effect. In the case of the vulcanisates cured with EV system, the linkage scission causes the sharp drop of tensile strength. The addition of amine-based antioxidant appears to improve ageing properties. However, the excessive antioxidant reduces tensile properties via a decrease in cross-link density.

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Section: Introductionmentioning

confidence: 99%

Relationship Among Thermal Ageing Degradation, Dynamic Properties, Cure Systems, and Antioxidants in Natural Rubber Vulcanisates

Pimolsiriphol

Sae‐Oui

Sirisinha

2007

Polymer-Plastics Technology and Engineering

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“…In the experiments, glycerol‐plasticized wheat gluten materials were prepared via thermoplastic process consisting of first mixing the components in an internal mixer operated under lower temperature to avoid crosslinking reactions occurring, and second thermoforming the obtained dough at higher temperature, which led to the formation of the three‐dimensional macromolecular network. Referring to rubber vulcanization process,15 rotorless curemeter was first applied to investigate vulcanization characteristic parameters of glycerol‐plasticized gluten dough, such as M H , M L , t 10 , and t 90 , which could be used to calculate the activation energy and reaction rate of crosslinking according to Arrhenius law.…”

Section: Introductionmentioning

confidence: 99%

Thermal, kinetic, and mechanical properties of glycerol‐plasticized wheat gluten

Pan¹,

Wang²,

Yuan³

2011

J of Applied Polymer Sci

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Glycerol-plasticized wheat gluten was prepared by mixing in an internal mixer equipped with sigma rotors, and then thermally compression-molded to form a sheet for crosslinking and tensile tests. Referring to rubber vulcanization process, rotorless curemeter was applied to test the vulcanization characteristic parameters of the molded round samples, which could be used to calculate the activation energy and reaction rate of crosslinking occurring in wheat gluten when heated. Vulcanizing curves obtained show that the optimum temperature for processing glycerol-plasticized wheat gluten is 150 C, and that activation energy and reaction rate of crosslinking in wheat gluten plasticized with 20 wt % glycerol reach minimum and maximum values, respectively. In addition, glycerol content, plasticizing time, and temperature have significant effects on the mechanical properties of thermomolded wheat gluten plastics. The factors are closely related to the establishment of a covalent network resulting from the formation and rearrangement of disulfide bridges in wheat gluten.

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“…From this point onwards, the continued backbone scission will progressively break up the network, and the fragments released will act as plasticizers. In a vulcanizate, plasticization reduces both G ′ and G ″ . In which case, increasing levels of backbone scission will see the G ″( t ) vs. G ′( t ) plot falling downwards and to the left, as was anticipated in Figure .…”

Section: Resultsmentioning

confidence: 67%

“…A better comparison is seen in the cure rheometry of Dick, Pawlowski and Scheers . These studies embraced a host of different rubber polymers and found that, under standard conditions (same oscillating frequency, strain amplitude, and temperature), the peak in viscous torque came later in the cure for less resilient (higher T g ) elastomers.…”

Section: Resultsmentioning

confidence: 99%

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The Cole–Cole plot for cure: The cure and reversion of natural rubber

Willoughby¹

2016

J of Applied Polymer Sci

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Cure rheometry is routinely used in the rubber industry for processability assessment and cure-time determination. This article examines these rheological outputs in Cole-Cole format to explore what new insights can be gained from this alternative data plot. It differs from the conventional Cole-Cole treatment in its application to a reacting system. The plots described here are therefore of G 00 (t) vs. G 0 (t). Initially some attention is directed to the basics of the Cole-Cole treatment and the likely features to be expected when applied to systems undergoing both cure and reversion. This article goes on to consider examples of both by studying a natural rubber vulcanization at temperatures of 160 8C and above. Through the Cole-Cole approach, it is thought possible to identify the competition between intermolecular and intramolecular sulfurization, and between crosslink and main-chain scission. The approach offers considerable potential to expand the capabilities of cure rheometry.

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Alternate instrumental methods of measuring scorch and cure characteristics

Cited by 28 publications

References 7 publications

Relationship Among Thermal Ageing Degradation, Dynamic Properties, Cure Systems, and Antioxidants in Natural Rubber Vulcanisates

Relationship Among Thermal Ageing Degradation, Dynamic Properties, Cure Systems, and Antioxidants in Natural Rubber Vulcanisates

Thermal, kinetic, and mechanical properties of glycerol‐plasticized wheat gluten

The Cole–Cole plot for cure: The cure and reversion of natural rubber

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