• Elastomers and Composites
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• v.51 no.2
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• pp.128-137
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• 2016

The effect of the surface area of silicas on their reinforcing performance to styrene-butadiene rubber (SBR) compounds was systematically investigated. The feasibility of the Brunauer-Emmett-Teller surface area ($S_{BET}$) as a parameter representing the characteristics of the silicas was discussed compared to the mesopore volume, c value, oil absorption, and uptake of silane. The increase in $S_{BET}$ of silicas caused a considerable increase in Mooney viscosity, minimum torque, and hysteresis loss of the silica-filled SBR compounds, while significantly enhancing their abrasion property. These changes were explained by the attrition between the hydrophilic silica surface and the hydrophobic rubber chains. As expected, the change in $S_{BET}$ did not induce any remarkable changes in the cure, processing, tensile, and dynamic properties of the silica-filled SBR compounds because the crosslinking density of the rubber chains mainly determined these properties.

• Elastomers and Composites
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• v.53 no.2
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• pp.67-74
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• 2018

Magneto-rheological elastomers (MREs) are smart materials in which the inherent stiffness and damping properties can be changed by the influence of an external magnetic field. The magneto-rheological (MR) effect depends on the orientation characteristics of the dispersed magneto-responsible particles (MRPs) in the matrix. In this study, natural rubber (NR) and ethylene propylene diene rubber (EPDM) were blended and used as a matrix of an MRE. EPDM was pre-cured before blending with NR. The Mooney viscosity, curing characteristics, and mechanical properties were analyzed with various pre-curing conditions of EPDM and the NR/EPDM blend. The results show that excellent mechanical properties of the NR/EPDM blend-based MRE were obtained when the pre-curing time of EPDM was 60 min. The aging property of the NR-based MRE was improved by the introduction of pre-cured EPDM. Also, the anisotropic MRE showed a higher MR effect than that of the isotropic MRE.

• Elastomers and Composites
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• v.50 no.3
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• pp.159-166
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• 2015

Silica which is used for reinforcing filler in tire industry is widely known as eco-friendly material exerting $CO_2$ reduction effect through decrease of rolling resistance and improvement of wet grip. Generally silica is classified as a highly polar filler because it contains a large number of silanol (Si-OH) group on its surface. And also silica gives a lower reinforcing effect than carbon black due to its poorer rubber-filler interaction. Therefore silica is treated with silane coupling agent or activator, then following the conventional rubber blend method, vulcanized sheets were prepared using a hot press, and cure characteristics, mechanical properties and abrasion resistance of the test specimens were investigated. It was found that with an increase in the silane coupling agent content the tensile strength, 300% modulus and abrasion resistance increased while Mooney viscosity decreased and crosslink density slightly increased with an increase of activator.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.47-51
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• 2019

The three different polymer compounds were manufactured with the three different fire retardant (silane coated magnesium dihydroxide) contents, 180, 200, 220 phr, for making cable sheath for ship industry. In the research, ethylene-vinylacetate, polyethylene as matrix polymers and ethylene-vinylacetate grafted maleic anhydride as coupling agent were selected for compounding with fire retardant, closslinking agent, plasticizer, and other additives. In the evaluation. ΔT, Mooney viscosity, and tensile strength increased with the content of fire retardant. But it was found that too much fire retardant damaged aging resistance and cold resistance of the polymer compound.

• Macromolecular Research
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• v.8 no.4
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• pp.192-198
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• 2000

Cure characteristics and physical properties of carbon black-filled natural rubber (NR) compounds depending on the mixing procedure were studied using the compounds with different pre-final mixing (FM-1) stages. Carbon master batch (MB) and first and second remitting (1RM and 2RM) stages were employed as the FM-1 stage. Bound rubber content of the FM compound decreased with increasing the mixing steps. This was due to the decrease of the molecular weight distribution of the polymer by the rubber chain scission during the mixing. The Mooney viscosity decreased with increasing the mixing steps. Cure characteristics of the compounds were found to be different with the mixing procedures. The cure times of the compound became slower by increasing the number of the mixing steps. This was explained by the length of rubber chain, the carbon black network, distribution of the curatives in the compound, and immobilization of the polymeric segments. Modulus and tensile strength of the vulcanizate did not show a specific trend with the mixing procedure. Fatigue life of the vulcanizate increased by increasing the mixing stages.

• Journal of the Korean Graphic Arts Communication Society
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• v.18 no.2
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• pp.83-101
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• 2000

In this experiment butadiene rubber(BR)/acrylonitrile butadiene rubber(NBR) blends was prepared and then the applicability of BR/NBR blends as printing rubber roller was examined. With the aid of open 2-roll mill, BR, NBR and another chemical additives were compounded. Then rubber vulcanizates were manufactured by hot press and maximum torque, Mooney viscosity, mechanical properties and oil resistance of the test specimens were measured. With prolonged oil aged treating time, BR/NBR blends became soft and so the hardness of blends decreased. It could be explained by the swelling of rubber matrix with oil penetration in to rubber molecules. The undesirable low value of oil resistance of BR was significantly improved by blending BR with NBR.

• Elastomers and Composites
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• v.54 no.1
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• pp.40-53
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• 2019

The physical properties of chloroprene rubber (CR) compounds reinforced with networked silicas were investigated by comparing them to those reinforced with conventional silica to observe the effect of the organic connection bonds combining silica particles on their cure, tensile, and aging performance. The introduction of networked silica to CR increase in silica content to 80 phr in rubber, while the content of conventional silica was limited to 60 phr. The CR compounds reinforced with networked silica showed higher resistance to combustion. The gradual increases in delta torque, Mooney viscosity, and modulus of silica-filled CR compounds with silica content were mainly attributed to the specific interaction between the chlorine atoms of CR and the hydroxyl groups of silica. The CR compounds reinforced with networked silica showed low compression set and heat build-up and maintained their high modulus even after thermal, oil, and ozone aging.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.42-47
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• 2019

The four different polymer compounds were manufactured to make cable sheath for ship industry. Two kinds of ethylene-vinyl acetate (EVA) were selected as main matrix polymers for compounding with fire retardant, crosslinking agent, filler, plasticizer, and other additives. The properties of the four compounded materials were investigated with the contents of fire retardant, silane coated aluminum hydroxide (S-ATH). Rheology, Mooney viscosity, and tensile strength increased with S-ATH contents by reinforcing effect. With increasing fire retardant amount, fire resistance increased, but cold resistance didn't show an obvious enhancement due to polar effect of vinyl acetate in EVA.

• Elastomers and Composites
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• v.46 no.4
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• pp.329-334
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• 2011

In general, butyl rubber(IIR : isobutylene isoprene rubber) has excellent gas permeability resistance and impact absorbance property as low resilience elastomer. In this experiment butyl rubber blends with EPDM(ethylene propylene diene monomer) were prepared by mechanical mixing method. Curing behavior, physical properties and ozone resistance etc. were subsequently examined. Measurement results of gas transmission rate test shows that butyl rubber contents above 50 wt% showed significant decrease in gas permeability resistant property. However, in butyl rubber/EPDM blend, EPDM contents above 25 wt% indicates no surface change due to improvement of ozone resistance under the condition of 50 pphm, $50^{\circ}C$, 120 hrs.

• Elastomers and Composites
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• v.55 no.3
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• pp.167-175
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• 2020

Various studies have been conducted to improve silica dispersion of silica filled tire tread compounds; among them, silica wet masterbatch (WMB) technology is known to be suitable for manufacturing silica filled compounds that have high silica content and high dispersibility. Till now, the WMB study is focused on the natural rubber (NR) or emulsion styrene-butadiene rubber (ESBR) that does not have a silica-affinity functional group, and a study of NR or ESBR having a silica-affinity functional group is still not well known. Unlike the dry masterbatch technology, the WMB technology can solve the problems associated with the high Mooney viscosity when applied to silica-friendly rubber. However, a coagulant suitable for each functional group has not yet been determined. Therefore, in this study, different coagulant applied silica WMB was prepared by applying calcium chloride, sulfuric acid, acetic acid, and propionic acid by using a carboxyl group functionalized reversible addition fragmentation chain transfer ESBR. The evaluation of the WMB compounds revealed that the calcium chloride added WMB compound showed excellent silica dispersion, abrasion resistance, and rolling resistance.