• Journal of the Korean Chemical Society
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• v.15 no.6
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• pp.359-366
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• 1971

The extended Huckel calculations on five organic accelerators of vulcanization have been carried out. Various MO quantities e.g., electron populations and AO coefficients, are used to explain accelerator reactivity of the compounds. Results of these analyses lead us to support free radical mechanism of acceleration in vulcanization.

• Polymer(Korea)
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• v.37 no.3
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• pp.269-275
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• 2013

Thiuram (DPTT, TMTD), thiazole (MBT, MBTS), sulfenamide (CBS, NOBS), and zinc containing thiuram (dithiocarbamate) (ZDBC) type accelerators were added into silica and carbon black filled natural rubber (NR) compounds. Their effects on vulcanization time and rate were compared. The vulcanization rate of thiuram type accelerator added compounds showed the fastest rate, followed by thiazole and sulfenamide types. Silica filled natural rubber (NR) compounds showed a slower vulcanization time ($t_{s2}$, $t_{10}$, $t_{90}$) and lower cure rate index (CRI) than carbon black filled ones upon each accelerator.

• 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.

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

• 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 $T_{max}$.

• Elastomers and Composites
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• v.14 no.2
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• pp.83-102
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• 1979

The purpose of this dissertation is to study some of the vulcanization characteristics of rubber-bound antioxidants such as G-1, [N-(3-methacryloyloxy-2-hydroxypropyl)-N'-phenyl-p-phenylene diamine] and acryl, acrylamide & acrylester substituted hindered phenols. The influence of these antioxidants upon vulcanization characteristics in NR and SBR compounds in the presence of vulcanizing accelerators such as MSA, TT, DM, M & D was evaluated by means of Oscillationg Disk Cure Meter. The comparison was also made between the influence of rubber-bound antioxidants and that of conventional non-reactive antioxidants such as N-alkyl substituted PADA series. Regarding the influence of reactive type antioxidant G-1 mixed with accelerator TT upon vulcanization characteristics, rapid onset of vulcanization and higher degree of cross-linking were discovered, whereas in the case of accelerator M and DM, the result was slow onset of vulcanization and lesser degree of cross-linking. The comparison of vulcanizing characteristics among acrylic substituted hindered phenols as antioxidants was made under several vulcanization accelerator systems. Under such systems, MSA-S combined accelerator caused the onset of vulcanization to slow down and lowered the degree of cross-linking. Finally in the case of hindered phenol derivatives containing longer substituent, the delayed onset of vulcanization and the lowered degree of cross-linking could be discerned.

• Elastomers and Composites
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• v.19 no.1
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• pp.13-31
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• 1984

The purposes of this dissertation are to demonstrate that DSC theromoanaytical methods of vulcanization can provide useful informations on the vulcanization characteristics of industrial formulations and also provides the potential basis for a rapid and complete method of sulfur and vulcanizing accelerator analysis for quality control. The influences of those factors such as heating rate, scan temperature, vucanizing accelerator's type and concentration upon vulcanization exotherm in NR and NBR compounds in the presence of vulcanizing accelerators such as TMTD,MBTS,DPG,TMTM,CBS, and MBT were evaluated by means of DSC. In order to examine the credibility in the DSC method, the same samples which were used for DSC method were studied to compare the DSC results with the ODR (Oscillating Disk Rheometer) data. The results obtained were as follows 1. In the DSC dynamic experiments, the observed enthalpy results from vulcanization depends upon the heating rate; In the range of 2 to $20^{\circ}C/min$ of heating rate, as the heating rate was increased the enthalpy change was also increased. However, over the heating rate of $30^{\circ}C/min$ it was observed that the enthalpy change was decreased as the heating rate was further increased. Without regard to the change of enthalpy, tremendous instantaneous heat evolving was observed in the range of high heating rates. 2. For the samples which are added with various vulcanizing accelerators, the activation energies of vulcanization were as follows; 3. Regarding to the influences of vulcanizining accelerator's types upon the characteristics of vulcanization exotherm, NR and NBR compounds in the presence of thiuramsulphide compounds type accelerators such as TMTD, TMTM, were exhibited sharper and higher vulclanization exotherm than others. From the resuts of DSC thermograms which was distributed in even shape in the broad temperature range, it was clearly shown that the guanidine compounds type accelerator such as DPG acts as a delayed acting accelerator. 4. In the comparison of DSC and ODR results, the dependency of temperature in the cure rate and the observed conversions show good agreements between two results. 5. In the same curatives, by the comparison of glass transition temperatures, it was possible to predict relative values of maximum torques. Consequently, from the present studies, it is shown that the DSC thermoanalytical method can provide an alternate new method for rapid and complete quality control analysis of rubber industry.

• Elastomers and Composites
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• v.17 no.4
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• pp.215-225
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• 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 and Zn-MDC to SBR compound. Vulcanization characterstics and physical properties of the combined accelerators have been studied by means of the Mooney viscometer, the Monsanto disc rheometer, tensile testing machine, aging chamber and so on. According to the test results, DPG, MBT and Zn-MDC system have show faster Mooney scorch time and optimum cure time than other systems. The Vulcanizate comprise of DPG, MBT and TMTD accelerator system has taken adventage of tensile strength, elongation, 100% modulus, resilience, compresion set.

• Elastomers and Composites
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• v.22 no.4
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• pp.333-339
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• 1987

A modern kinetic evaluation method for nonisothermal reactions measured with Differential Scanning Calorimetry(DSC) is presented. It is based on multiple linear regression analysis using a number of curve points in a selectable range of conversion. The obtained kinetic data are the basis to compute a reaction process under any condition e.g. isothermal or adiabatic. The DSC measurements was performed on a Mettler TA3000 SYSTEM with the built in evaluation software. Mainly the following reactions are discussed: vulcanization of natural rubber compounds containing vulcanizing accelerators. The purpose of this work is to analyse the vulcanization kinetics of typical NR vulcanization systems using DSC. These systems were chosen because they are typically reactive elastomer and are commercially important.

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