• Journal of Adhesion and Interface
• /
• v.3 no.2
• /
• pp.30-39
• /
• 2002

The effect of cure accelerator content on the change in crosslink density by thermal aging was studied for silica-filled natural rubber (NR) vulcanizates. Influence of silane coupling agent was also investigated. N-tert-Butyl-2-benzothiazole sulfenamide (TBBS) and bis-(3-(triethoxysilyl)-propyl)-tetrasulfide (TESPT) were used as a cure accelerator and a silane coupling agent, respectively. The crosslink density increased by thermal aging and the increasing level became larger as the aging temperature increased. The degree of crosslink density change of the vulcanizates without the silane coupling agent was larger than that of the vulcanizates containing the silane coupling agent. For the vulcanizates silane coupling agent, the activation energy for the crosslink density change decreased with increase of the cure accelerator content in the vulvanizate.

• Elastomers and Composites
• /
• v.13 no.3
• /
• pp.197-206
• /
• 1978

반응속도면(反應速度面)에서의 동력학적(動力學的) 연구결과(硏究結果)에 의(依)하면 2-메르캅토벤쪼티아졸(MBT)은 N-t-부틸-벤쪼티아졸썰펜아미드(BBTS) 또는 2-(4-몰폴리노티오) 벤쪼티아졸(OBTS)과 같은 가황촉진제(加黃促進劑)들 보다는 N-(싸이클로헥실티오)프탈이미드(CPT)가 훨신 더 빨리 반응(反應)한다는 사실(事實)을 탐지(探知)하였다. 또한 우수(優秀)한 가황지연제(加黃遲延劑)는 MBT와 급속(急速)히 반응(反應)하여야 하지마는 실소(室素)와 황(黃)과의 화학결합(化學結合)이 너무 약(弱)하여 내열안정성(耐熱安定性)이 없음으로 아무리 MBT와 빠른 속도(速度)로 반응(反應)하여도 좋은 가황(加黃)지연제가 될 수는 없다. 예를들면 N-(싸이클로헥실티오-O-벤쪼의 썰펜이미드(CTBS))는 CTP보다 더 빨리 MBT와 반응(反應)하지만 열안정성(熱安定性)이 부족(不足)하여 가황(加黃)지연제로서는 CTB 보다 좋지 못하다.

• Polymer(Korea)
• /
• v.36 no.2
• /
• pp.235-244
• /
• 2012

A thiazole type accelerator MBT (2-mercapto benzothiazole) was added into silica filled natural rubber (NR) compound with various concentrations (0, 1, 2, 3, 4 phr). The effects of MBT on the cure rate, mechanical property, degree of rubber-filler interaction (${\alpha}_F$), crosslinking density, and viscoelastic property ($tan{\delta}$) were investigated. As accelerator concentration increased, the $t_{s2}$ and $t_{90}$ decreased and the crosslinking density and modulus at 300% elongation increased. The tensile strength and elongation increased up to 3 phr and no further increased at 4 phr. The $tan{\delta}$ value measured at room temperature was higher than that of the $70^{\circ}C$. The ${\alpha}_F$ value was not affected by the addition of MBT. The mechanisms for the vulcanization rate were reviewed.

• Elastomers and Composites
• /
• v.21 no.1
• /
• pp.13-19
• /
• 1986

The effects of several vulcanizing accelerators on the determination of kinetic parameters of natural rubber vulcanizate was studied by DSC. Kinetic parameters were determined by means of the calculation procedures of Borchardt-Daniels and Oscillating Disk Rheometer (ODR) cure curve analysis, using both DSC exothermal thermogram and ODR cure curve. In order to examine the credibility in the DSC method the same compound which was und for DSC method was used for the comparison with the results of ODR data. Upon this method, kinetic rate constant (k), and Arrehenius parameter (Ea, ko, n) have been determined for rubber compounds via a new method using DSC thermogram and ODR cure curve. In the comparison of DSC and ODR results, kinetic parameters has shown good agreements between two results. Consequently, from the present studies, it is shown that the DSC thermoanalytical method can provide an alternate new method of kinetic study of rubber vulcanization.

• Elastomers and Composites
• /
• v.17 no.3
• /
• pp.151-158
• /
• 1982

The purpose of this study is to get comparitive results on the combined accelerator systems comprised of MBT, MBTS, DPG and CBS with TMTD, TMTM, Zn-MDC and DPG to SBR compound. Vulcanization characterstics and physical properties of the combined accelerators have been studied by mean of the Mooney viscometer, tensile testing machine, aging chamber and so on. According to the test results, TMTD with DPG system has shown faster Mooney scorch time than other system. The vulcanizate comprise of Zn-MDC with DPG and TMTD with DPG accelerator system has taken advantage of heat resistance.

• Elastomers and Composites
• /
• v.5 no.1
• /
• pp.75-79
• /
• 1970

• Polymer(Korea)
• /
• v.38 no.3
• /
• pp.406-410
• /
• 2014

Zinc ion containing thiuram type accelerator zinc dibutyldithiocarbamate (ZDBC) was compared to other thiuram type accelerators (tetramethylthiuram disulfide (TMTD) and dipentamethylenethiuram tetrasulfide (DPTT)) in silica filled natural rubber (NR) compound upon vulcanization and mechanical properties (modulus, tensile strength, and elongation %). ZDBC added compound showed the fastest cure time (t10) and the highest reinforcement index (R.I.) among them and showed a marching behavior. The mechanism was reviewed and a new mechanism was proposed.

• Elastomers and Composites
• /
• v.34 no.1
• /
• pp.11-19
• /
• 1999

Rebound, storage and loss modulus, and tan ${\delta}$ were investigated on cured rubbers with various ratios of sulfur to accelerator and the volume fraction of carbon black in the cured rubbers. The rebound was increased as the sulfur to accelerator ratio and the volume fraction of carbon black decreased. The storage modulus decreased as the loading of carbon black and the strain increased regardless of the cure systems. The network structure formed by filler-filler interaction was destroyed above 6% strain regardless of the loading of carbon black, because constant storage modulus was shown at the higher strain than 3% for $40{\sim}50phr$ loading of carbon black and at the higher strain than 6% for 60 phr and above loading of carbon black. Little effect on loss modulus was found at the low loading of carbon black, but the peak of loss modulus was shown at 1% strain as the loading of carbon black was increased. Tan ${\delta}$ increased as the loading of carbon black and the strain were increased regardless of the cure system, and maximum tan ${\delta}$ was shown at 2% strain regardless of the loading of carbon black.

• Elastomers and Composites
• /
• v.34 no.4
• /
• pp.341-349
• /
• 1999

In this study, heat and crack resistance of natural rubber (NR) compounds was evaluated. To prevent the effects of the crosslinking system, a conventional vulcanization system was selected, where the accelerator/sulfur ratio was fixed to 0.25. Vulcanizates containing phenylenediamine showed high tensile strength and tear strength compared to other vulcanizates because phenylenediamine can cause additional crosslinking and high dispersion In the vulcanizates. In the pure shear test, vulcanizates containing phenylenediamine showed an excellent tearing energy which was due to the irregular crack path, and showed excellent heat and crack resistance which was also due to the good dispersity of antioxidant and additional crosslinks in the rubbber vulcanizates.

• Applied Chemistry for Engineering
• /
• v.22 no.4
• /
• pp.411-415
• /
• 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 $T_{max}$.