• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.671-671
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• 1995

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.173-185
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• 2018

Effects of three different types of dispersions and flow improving additives composed with fatty acid esters, fatty acid metal salts and amide compound on the vulcanization and the mechanical properties properties of rubber compounds of EPDM and carbon black as fillers. were investigated using Mooney viscometer, moving die rheometer, hardness tester, and universal test machine. The aging characteristics of vulcanized EPDM compounds were also investigated. The Mooney viscosity measured at $125^{\circ}C$ showed a tendency to decrease in the order of amide type> metal salt type > ester type additive. Scorch time showed little or no difference with the addition of ester or metal salt type additives, but the amide type additive shortened a scorch time more than one minute. Rheological measurement data obtained at $160^{\circ}C$ showed that the vulcanization time was faster for metal salt type and amide type additive systems. Delta torque values of EPDM compound increased with metal salt type and amide type additives, but slightly decreased with ester type additive. The tensile strength of the EPDM compound was greatly improved when an ester type additive was added, but the amide type or metal salt type additive had no significant effect. The elongation was significantly improved for metal salt type additive, while the rest were not significantly affected. The tear strength of the EPDM compounds increased with the addition of all kinds of additives, and it increased remarkably in the case of metal salt type additive. Hardness of the EPDM compounds was nearly same value regardless of additive types. The thermal aging of the EPDM blend at $100^{\circ}C$ for 24 h showed little change in the case of metal salt type or amide type additive, but the elongation tends to decrease by 10-20% for all EPDM compounds containing additives.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.153-160
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• 2013

An orthotropic magneto-rheological rubber composite (MRRC) based on a general-purpose rubber can be manufactured by using an electromagnetic device during the curing processes of rubber mixtures. The magnetic transmissivity of MRRCs increases with the iron particle (IP) content, and that of aligned MRRCs with a 2-T magnetic field is 1.8 to 2 times higher as compared to that of randomly dispersed MRRCs. The effect of a 2-T magnetic field on carbon nanotube (CNT) reinforced MRRC has been identified clearly, and the magnetic transmissivity is found to be 3.7%. The compressive stress of MRRC (IP 90 + CNT 5, 2 T alignment) under a magnetic field of 0.49 T is 2.1 times higher as compared to that of the matrix. The MR effect of MRRC increases with the IP content, and that of aligned MRRC with the IP 90 and 2 T magnetic field is 20.4%. It is confirmed that the magnetic field when making the specimen and when performing the compression test greatly impacts the compression characteristics.

• Polymer(Korea)
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• v.25 no.4
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• pp.503-511
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• 2001

Present silica dispersing agents are based mainly on fatty acid derivatives of Zn, K and mixture of fatty acid and metallic soaps are used to increase activity. The viscosity of silica filled rubber is lowered by Zn-K soap type silica dispersing agent, thus fluidity of hydrocarbon chains and processibility is improved. Silica dispersing agent should not exert an influence on chracteristics of vulcanization. But scorch and curing time is shortened by Zn-K soap type silica dispersing agent. A newly developed silica dispersing agent, which is a nonmetal type agent, reduced the viscosity and hardness of silica compounding rubber, and the highly increased degree of dispersion of silica is caused by interaction of silica and rubber. Also it did not affect the curing characteristics and scorch stability of silica compounding rubber.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.2
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• pp.308-318
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• 1988

The liquid disintegration and characteristics of atomization through the swirl nozzle is affected by injection pressure and injection time when the liquid is injected intermittently. These transient phenomena are investigated by electronic controlled-fuel injection nozzle. The effect of injection conditions on disintegration of liquid injected through nozzle is observed photographically by using delay circuit. Droplet size of the element of the sample is measured by the liquid immersion sampling technique. SMD of droplets is varied with time and is decreased as the injection pressure increases. As the injection pressure increases, the maximum diameter of droplet and diameter of droplet which has the maximum droplet number decrease. Spray angle is not affected on injection pressure and change of spray angle with time is associated with needle movement.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.144-148
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• 2011

Various types of accelerators, thiuram (TMTD), thiazole (MBTS), and sulfenamide (CBS) are added into a silica filled natural rubber (NR) compound. Their effects on vulcanization properties are also investigated. TMTD shows a fast vulcanization rate and a higer maximum torque ($T_{max}$), as well as excellent mechanical properties (hardness, 300% modulus, tensile strength, elongation). MBTS shows a moderate vulcanization rate, a lower $T_{max}$, and mechanical properties. Finally, CBS shows a slow vulcanization rate but excellent mechanical properties. The same vulcanization trend can be found in carbon black filled NR compounds.

• Polymer(Korea)
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• v.25 no.1
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• pp.63-70
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• 2001

The objective of this study was to investigate the effect of cure type on the processing and physical properties under conditions of similar stress-strain properties. On the carbon black filled natural rubber(NR) based compound, the induction time decreased, but the cure rate became fast with increasing loading of sulfur donor agent. Tensile strength was little affected on the curing type. However, elongation generally decreased with increasing accelerator. Effect of cure type on the blow-out properties was followings: CV

• Polymer(Korea)
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• v.27 no.5
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• pp.436-442
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• 2003

Thermosetting elastomer such as EPDM (Ethylene Propylene Dien Rubber) has been applied to the sponge weatherstrip of a vehicle as a main material. However, the thermosetting elastomers have limited recycling and have brought about the environmental problems. Furthermore, many steps of the manufacturing process such as formulation, mastication and vulcanization make difficult to control uniformity of the endproducts. These problems of current EPDM weatherstrip necessitated development of a new recyclable material, Thermoplastic Vulcanizates (TPV). In this study the influence of the water contents, and the processing conditions. On the foam density and structure in water blowing process was carried out. We found that TPV also can be foamed with water, maintaining the uniformity form this study. Therefore, many inevitable problems of EPDM weatherstrip can be solved, and this new technique is expected to take a roll of making a breakthrough in the rubber industry.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.411-415
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• 2011

Various types of accelerators, thiuram (TMTD, DPTT), thiazole (MBT, MBTS), and sulfenamide (CBS, NOBS) are added into a silica filled natural rubber compound. Their effects on vulcanization and mechanical properties are investigated. TMTD showed the fastest vulcanization rate, the higer maximum torque ($T_{max}$), and the excellent mechanical properties (300% modulus, tensile strength, elongation). MBT and MBTS showed an intermediate vulcanization rate between thiuram and sulfenamide type and added ones, and also showed the lower $T_{max}$ and mechanical properties compared to that of other compounds. Finally, NOBS showed the slowest vulcanization rate and the lower mechanical property but the moderate $T_{max}$.

• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.403-409
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• 2009

In the 1840s, Goodyear found out sulfur cure system, but cure time was too slow. So producing of rubber product takes a long time. In 1904, Oenslager et al. found that aniline is accelerated sulfur cure system. Recently, many rubber industries needed high yield and good quality. So, many researchers have studied a rubber system with fast vulcanization time and good mechanical properties. In this study, cure characteristics and mechanical properties of NR/BR compounds by accelerator with MBTS(2,2' Dithiobisbenzothiazole), TMTM(Tetramethylthiuram Monosulfide), ZDMC (Zinc dimethyldithiocarbamate), CBS(N-Cyclohexyl benzothiazolyl-2-sulfenamide), DPG(Diphenylguanidine) were evaluated. The results of the study indicate that cure charateristics($t_{90}$: 235 sec, $T_{max}$: 5.77 Nm) and mechanical properties (100, 300% modulus : 2,180, 5.656 Mpa and tear strength: 59.58 kgf/cm) of NR/BR compounds shows efficient acceleration with MBTS 1.5 phr, TMTM 0.5 phr, DPG 0.15phr. This is due to the synergistic activity of ternary accelerator system in rubber vulcanization.