• Journal of the Korean Chemical Society
• /
• v.6 no.2
• /
• pp.99-103
• /
• 1962

The usefulness of a propionylated paper chromatography to the identification of various insoluble organic antioxidants in rubber vulcanizates was studied. Purified commercial antioxidants and commercially mixed antioxidants could be identified by the propionylated paper chromatography. Antioxidants were identified by the propionylated paper chromatography from acetone extract of pure gum vulcanizates, which were either unaged or aged in Geer-Oven. The $R_f$ values from acetone extracts of vulcanizates were a little lower than those purified samples, but the colours and shapes of the spots support the identification. No spot could be obtained by the method from the aged vulcanizate containing antioxidant 200 (2,6 Di-tert-butyl-p-cresol). This indicates that the antioxidant was converted or decomposed to other compound after aging. It was concluded from the above results that the propionylated paper chromatography is useful to identify the antioxidants from vulcanizates and presents a key for elucidating the mechanism of the inhibition.

• Design & Manufacturing
• /
• v.1 no.1
• /
• pp.39-44
• /
• 2007

In recent, recycling of plastic material has became a major issue due to the landfills and environmental problem. This study investigated fluidity and hardness of thermoplastic vulcanizate(TPV), which is used for automobile component parts such as weather strip in order to replace ethylene propylene rubber (EPDM). So, using the spiral flow test mold, we conducted an experiment on fluidity and hardness of TPV according to injection molding conditions. As results of injection molding experiment, the recycled TPV's flow length was a little bit longer than virgin TPV and the hardness was decreased in case of using the recycled resin. Also, we investigated the morphology study by SEM photo.

• Elastomers and Composites
• /
• v.17 no.2
• /
• pp.77-90
• /
• 1982

The purpose of this study is to get comparative results on the combined antioxidant systems comprised of MHPPD with IPPD, MHPPD with PBN and MHIPPD with MB when they are individually added to NR and SBR compound. Vulcanization characterstics and physical properties of the combined antioxidants have been studied by means of the Mooney viscometer, the Monsanto disc rheometer and so on. According to the test results, MHPPD with IPPD system has shown faster cure rate, better optimum cure time and shorter scorch time than other systems. The vulcanizate comprised of the MHPPD with IPPD antioxidant system has taken advantage of heat resistance, fluid resistance and antiozone resistance.

• Journal of Adhesion and Interface
• /
• v.13 no.1
• /
• pp.1-8
• /
• 2012

The effect of the grafting ratio on the mechanical property and adhesion property of the grafted EPDM modified with methacrylic acid (MA) was investigated. The storage modulus of MA-grafted EPDM was maintained higher than that of cross-linked EPDM vulcanizate by sulfur, but it was observed that the storage modulus was decreased at elevated temperature because of the weakened secondary bonding. When the functional group for hydrogen bonding was introduced in EPDM, it had excellent mechanical properties by the aggregate between grafted EPDM molecules and crystallinity of MA. The bonding strength between EPDM and other rubbers was very low because EPDM has nonpolar property and low molecular interaction to others. The bonding strength was increased as increasing grafting ratio and it was excellent enough to break the rubber during the peel test when the grafting ratio was more than 10%.

• 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.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.

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

• Elastomers and Composites
• /
• v.42 no.2
• /
• pp.102-106
• /
• 2007

Water swelling behaviors of SBR vulcanizates with different reinforcing systems of carbon black, silica without a coupling agent, and silica containing a coupling agent were studied. Distilled water and 3.5% NaCl solution were used as swelling media. The water swelling ratios in the distilled water were higher than those in the salt solution. The water swelling ratios of the carbon black-filled samples were lower than those of the silica-filled ones. For the silica-filled SBR vulcanizates, the specimens without the silane coupling agent had higher water swelling ratios than those containing it. Water swelling behaviors of SBR composites with different 1,2-unit contents were also compared. The water swelling ratios tended to decrease by increasing the 1,2-unit content.

• Elastomers and Composites
• /
• v.22 no.3
• /
• pp.204-212
• /
• 1987

The purpose of this study is to investigate the reinforced effect between MGF treated silane coupling agents and rubber matrix under the configuration chemical bonds, also the effect of triazine thiol compounds. For this study, vulcanizates were prepared with fifteen different compounding formulas. Their vulcanization characteristics, physical properties were examined by means of the ODR(Oscillating Dist Rheometer), the tensile tester, the benzene swelling test. The results of this study obtained are as follows: 1. In the ODR test, the MA vulcanizate was the fastest one in terms of having reached to optimum cure time($t_{90}$) and, with the same formula, when MGF vulcanizates, the shortest optimum cure times has appeared. 2. The SA, SC vulcanizates were the best the other in the physical properties such as 100%modulus, 200%modulus, 300%modulus, tensile strength. The SB vulcanizate, with higher density of crosslinking than other vulcanizates. The vulcanizates, which were filled with MGF treated with silane coupling agents we were the higher density of crosslinking than vulcanizates filled with MGF only. 3. In aging properties, the silica vulcanizates appeared to be better than the other vulcanizates. The aging Properties of treated MGF vulcanizates were similar to the silica vulcanizates. The(CR+APS+silica) and(CR+APS+MCF) were easily crosslinked by exposure to the air, and the physical properties have been improved.

• Elastomers and Composites
• /
• v.40 no.3
• /
• pp.181-187
• /
• 2005

Changes of physical properties or NR vulcanizates with different cure systems by thermal aging were investigated. Two sulfur cure systems and one resole cure system were employed, and total contents of the curatives were varied. For the NR vulcanizates with sulfur cure systems, hardness and modulus after the thermal aging at $90^{\circ}C$ for 3 days were increased, but elongation at break and tensile strength were decreased. For the NR vulcanizates with resloe cure system, the physical properties after the thermal aging were decreased. The change of physical properties by the thermal aging was explained with the crosslink density change. The crosslink densities or the NR vulcanizates with sulfur cure systems were increased after the thermal aging, but those with resole cure system were decreased. Influence of the migration of antidegradant on the changes of physical properties was also investigated. However, the changes of physical properties by the thermal aging were not explained sufficiently with the migration of antigradant.