Assessing Effect of the Migration of A Paraffin Wax on the Surface Free Energy of Natural Rubber

Ansarifar, Ali; Critchlow, Gary W.; Guo, R.; Ellis, Robert J.; Haile-Meskel, Yared; Doyle, Barry

doi:10.5254/1.3557001

Cited by 14 publications

(7 citation statements)

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“…Blooming in rubber may occur when partly soluble compounding ingredient is used at a level in excess of its solubility limit at a given temperature. Blooming is an outcome of a controlled diffusion process [2], while diffusion can be explained as a movement of soluble compounding ingredients driven by a distraction in the equilibrium. Solutions of the compounding ingredient in rubber compound are known to act similarly to solutions of low molecular weight liquids and are characterized by the same laws as for normal solutions.…”

Section: Introductionmentioning

confidence: 99%

Blooming of Compounding Ingredients in Natural Rubber Compounds under Different Peroxide Loading

Yasin¹,

Zawawi²,

Tahir³

et al. 2019

IJRTE

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Rubber compounds normally shows blooming phenomena whereby a thin layer of powdery material or films and oils formed on the surface. These blooms are usually low molecular weight compounding ingredients such as curing agents, accelerator, processing aids and activators that migrated to the surface. Excessive blooming can degrade the vulcanized rubber and reduced its quality. It is therefore necessary to determine the compounding ingredients that bloomed in an effort to reduce the effect of blooming. This study was aimed at identifying the compounding ingredients that dominate the blooming process. Sulphur, paraffin wax and zinc diethyldithiocarbamate (ZDEC) with specific functions were added as compounding ingredients in natural rubber (SMR L). Dicumyl peroxide were added as the curing agent at several loadings. The rubber compounds were cured at 150oC in the presence of dicumyl peroxide as curing agent at several loadings. They were stored under room temperature for blooming to take place. Blooms were analysed using FTIR and EDX. EDX analysis detected the major element present in the blooms to be carbon at 53.5% abundance. Similarly, FTIR results produced high intensity of C-H band at 2916 cm-1 and 722 cm-1 which are due to stretching and bending vibration of C-H paraffinic. It was concluded that paraffin wax preceded sulphur and ZDEC in blooming of SMR L.

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Section: Introductionmentioning

confidence: 99%

Blooming of Compounding Ingredients in Natural Rubber Compounds under Different Peroxide Loading

Yasin¹,

Zawawi²,

Tahir³

et al. 2019

IJRTE

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“…4 Studies have shown that accelerators, e.g., sulfenamide types, diffuse to the surface because they are partly soluble in most rubbers. 5 This diffusion can be detrimental to rubber properties such as loss of adhesion, 6,7 and also to the durability and performance of rubber in service as well as to health, safety, and the environment.…”

Section: Introductionmentioning

confidence: 99%

Measuring effect of the blooming of chemical curatives on the rate of cyclic fatigue crack growth in natural rubber filled with a silanized silica nanofiller

Saeed

Ansarifar

Ellis³

et al. 2011

J of Applied Polymer Sci

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Two rubber compounds with different amounts of chemical curatives were prepared by mixing natural rubber with a high loading of a sulfur‐bearing silanized precipitated amorphous white silica nanofiller. The chemical bonding between the filler and rubber was optimized via the tetrasulfane groups of the silane by adding a sulfenamide accelerator and zinc oxide. The rubber compounds were cured and stored at ambient temperature for 65 days before they were tested. One compound showed extensive blooming as a function of storage time. Thin tensile strips of the rubber vulcanizates containing an edge crack were repeatedly stressed at constant strain amplitude and test frequency at ambient temperature and crack length c was measured as a function of the number of cycles n. The cut growth per cycle, dc/dn, was calculated and plotted against the tearing energy, T. The blooming of the chemical curatives increased dc/dn by up to an order of magnitude at a constant T. This was due to the reagglomeration of the chemical curatives in the rubber and also within a thin layer approximately 15 to 20 μm in size beneath the rubber surface. Under repeated stressing, cracks grew through the relatively weak agglomerated areas in the rubber and this caused the rate of crack growth to increase at a constant T. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

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“…Studies have shown that accelerators, e.g., sulfenamide types, diffuse to the surface because they are partly soluble in most rubbers 3. This diffusion can be detrimental to rubber properties such as loss of adhesion4, 5 and also to health, safety, and the environment.…”

Section: Introductionmentioning

confidence: 99%

Effect of the blooming of chemical curatives on the cyclic fatigue life of natural rubber filled with a silanized silica nanofiller

Saeed

Ansarifar

Ellis³

et al. 2010

J of Applied Polymer Sci

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When partly soluble chemical curatives are mixed with raw rubber, they migrate to the rubber surface, which can be detrimental to the rubber properties. Two rubber compounds with different amounts of curatives were prepared by mixing natural rubber with a high loading of precipitated amorphous white silica nanofiller. The silica surfaces were pretreated with bis(3-triethoxysilylpropyl)-tetrasulfide coupling agent to chemically adhere silica to the rubber. The chemical bonding between the filler and rubber was optimized via the tetrasulfane groups of bis(3-triethoxysilylpropyl)-tetrasulfide by adding accelerator and activator. The rubber compounds were cured and stored at ambient temperature for up to 65 days. One compound showed extensive blooming as a function of storage time. The cyclic fatigue life of the rubber vulcanizates was subsequently measured at a constant strain amplitude and test frequency at ambient temperature. The blooming of the chemical curatives reduced the cyclic fatigue life of the rubber vulcanizate by more than 100%. The migrated chemical curatives produced a thin layer approximately 15 lm in size beneath the rubber surface. When the rubber was stressed repeatedly in the fatigue test, cracks initiated in this layer and subsequently grew, causing the fatigue life of the vulcanizate to decrease.

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Assessing Effect of the Migration of A Paraffin Wax on the Surface Free Energy of Natural Rubber

Cited by 14 publications

References 0 publications

Blooming of Compounding Ingredients in Natural Rubber Compounds under Different Peroxide Loading

Blooming of Compounding Ingredients in Natural Rubber Compounds under Different Peroxide Loading

Measuring effect of the blooming of chemical curatives on the rate of cyclic fatigue crack growth in natural rubber filled with a silanized silica nanofiller

Effect of the blooming of chemical curatives on the cyclic fatigue life of natural rubber filled with a silanized silica nanofiller

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