• Transactions of the Korean hydrogen and new energy society
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• v.31 no.5
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• pp.453-458
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• 2020

In this study, ethylene-propylene-diene monomer (EPDM) rubbers reinforced with various particle size of carbon black were prepared and tested. We followed recently published CSA/ANSI CHMC2 standard "the test methods for evaluating material compatibility in compressed hydrogen applications-polyemr". Measurement of change in hardness, tensile strength and volume were performed after exposure to maximum operating pressure, 87.5 MPa, for 168 hours (1 week). Once EPDM was exposed to high-pressure hydrogen, the samples experience volume increase and degradation of the physical properties. Also, after the dissolved hydrogen was fully eliminated from the specimens, the hardness and the tensile properties were not recovered. The rubber reinforced with smaller sizes of carbon black particles showed less volume expansion and decrease of physical properties. As a result, smaller particle size of carbon black filler led to more resistance to high-pressure hydrogen.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.2
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• pp.135-140
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• 2020

An experimental study was conducted using the tracking wheel test (IEC 62217) method for evaluating the performance of insulator materials, in particular ethylene propylene diene monomer (EPDM) and silicone rubber. In addition, we studied the tracking characteristics resulting from applying the same method for the shape of the insulator housing, that is, the performance of regular and alternating sheds. The evaluation parameters were leakage current, surface characteristics, SEM, EDX, hydrophobicity, and temperature distribution; likewise, we applied the commercial frequency dry (and wet) flashover voltage test. We found that the regular shed had a greater leakage current than the alternating shed and that the recovery of the hydrophobicity in terms of rest time was greater than that of the EPDM in terms of leakage current. All of the regular-shed insulators of silicone rubber had tracking traces and choking on the sheath parting line, while the alternating shed showed only choking at the interface but no tracking traces. Therefore, it can be concluded that the commercial frequency wet flashover voltage of the silicone rubber with regular shed before and after the tracking wheel test is higher than that of the alternating shed.

• Elastomers and Composites
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• v.35 no.2
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• pp.115-121
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• 2000

In comparison with thermosetting rubber, thermoplastic elastomer (TPE) has various advantages such as simple processing, short cycle time and recycling of scrap. These advantages can lead to development of the high value-added rubber products due to reduction of the waste material, manufacturing cost and the defected product. This article involves a dynamic vulcanization method for EPDM/polypropylene blend, and the manufacturing of a fixed glass weather-strip by glass insert molding method using the blend. In order to investigate mechanical properties of the product, tensile strength, elongation, hardness and specific gravity were measured. Also morphological study was carried out using SEM. Developments of an efficient system of production and automatic process by molding of TPE and glass simultaneously are expected.

• Elastomers and Composites
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• v.52 no.3
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• pp.194-200
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• 2017

After the grafting of methacrylic acid (MA) to ethylene propylene diene monomer (EPDM), a new peak at $1704cm^{-1}$ corresponding to the carboxylic acid group was observed in the infrared (IR) spectrum. This characteristic MA molecule peak grew larger as the MA contents were increased. After casting films were prepared from pure EPDM and MA-grafted EPDM, differential scanning calorimeter (DSC) measurements were made the pure EPDM exhibited a melting point of approximately $45^{\circ}C$ while that of the MA-grafted EPDM was $135{\sim}140^{\circ}C$. As the graft ratio of MA increased, the absorbed heat capacity increased at temperatures near $135{\sim}140^{\circ}C$, indicating that an increased amount of MA reacted. Furthermore, owing to the addition of crystalline MA, it is expected that strength of the elastomer will improve as the graft ratio increases, as a result of the increased number of hard segments.

• Elastomers and Composites
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• v.51 no.3
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• pp.175-180
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• 2016

Influence of amino acidic chemical on properties of maleic anhydride-grafted ethylene-propylene-diene terpolymer/zinc oxide (EPDM-g-MAH/ZnO) composites was investigated. 4-Aminosalicylic acid (ASA), 4-amino-2-methoxybenzoic acid (AMBA), 12-aminolauric acid (ALA), and glutamine (Gln) were employed as the amino acidic chemicals. Though small quantity (0.5 phr) of the amino acidic chemical was added to the EPDM-g-MAH/ZnO composite, the properties were notably changed. By adding the amino acidic chemical, the percent crystallinity and apparent crosslink density were reduced. Order of the percent crystallinity was related to that of the $pK_a$ values of amino acidic chemicals. By adding the amino acidic chemical, the basic tensile properties were on the whole improved. The experimental results were explained by the $pK_a$ values of amino acidic chemicals, change of zinc ionomer formation, and interactions between the additive and EPDM-g-MAH chain.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1045-1047
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• 2017

In this study, we focused on development of the all-in-one case insulation for end-burning solid rocket motors. Material of insulation used unvulcanized rubber based on EPDM/kevlar. In case of boots insulation, preforms was made by using hot press molding, and then the tape was inserted between two preforms for all-in-one curing in the case. Finally bladder method was applied for curing of insulation.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.984-990
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• 2014

Polymers are the most commonly used di-electrics because of their reliability, availability, ease of fabrication and cost. The commercial and industrial demand for advanced polymeric materials which are capable of being used in harsh environment is need of the hour. The study of the effect of electron beam irradiation on polymeric materials is an area of rapidly increasing interest. This paper discusses the resultant beneficial effects of electron beam irradiation on the SiR-EPDM blend having 50:50 composition. The changes in mechanical and electrical properties of SiR-EPDM blend which are exposed to three different doses of electron beam radiation namely 5 Mrad, 15 Mrad and 25 Mrad are presented. The irradiated blends are analyzed for their electro-mechanical and physico chemical properties. The electrical changes induced by irradiation are investigated by arc resistance, surface resistivity and volume resistivity measurements as per ASTM standards. The mechanical changes are observed by the measurement of tensile strength and elongation at break. Physico chemical investigation has been done using the FTIR, in order to investigate the irradiation induced chemical changes.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.92-95
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• 2012

The dual pulse rocket motor is a pressure vessel containing two pulse grains separated by a pulse separation device such as a fragile bulkhead. One of the important things in this systems is case insulation design using the excellent materials in the 1st stage pulse motor. We investigated manufacturing process of fabric/EPDM chamber insulations in order to protect the 1st stage pulse motor case with high intensity gas flow. Simulation motor connected with extension tube having FRP disc was designed to study ablation characteristics of insulation.

• Elastomers and Composites
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• v.37 no.4
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• pp.224-233
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• 2002

This study has investigated the flame retardant properties of EPDM rubber with the addition of various flame retardants. Carbon black, stearic acid, zinc oxide cross-linking agent were mixed with EPDM rubber to produce the base rubber E0 without the addition of flame retardants. Phosphorus flame retardant Tricrecyl phosphate(TCP) was added to E0 in 0.5, 1, 1.5, 2 phr to make E1~E4 samples and red phosphorus was added in 3, 6, 9, 12 phr to make E5~E8 samples. A flame retardant of the bromine family Decabromodiphenyloxide(DBDPO), and a chlorinated paraffin retardant of the chlorine family was added to E0 in 3, 6, 9, 12 phr to make E9~E12 and E13~E16 samples, repectively. Basic physical properties such as tensile strength, tear strength and hardness were measured for all the rubber samples with various flame retardant additions. There was no substantial differences. On the other hand, Oxygen index and UL94 were measured to study flame retardant properties. From oxygen index measurements E0 sample showed a value of 23.5%, indicating the improvement of flame retardant properties. Also from UL94 measurements, it was found that addition of red phosphorus resulted in maximum flame retardant effect. It was found that increasing the amount of addition resulted in decreasing combustion rate and improving flame retardant effect regardless of the kind of flame retardant.

• Clean Technology
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• v.5 no.2
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• pp.45-52
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• 1999

Recycling of red mud from the aluminium manufacturing process was investigated to be utilized as plastic fillers. High density polyethylene(HDPE), low density polyethylene(LDPE) and polypropylene(PP) were found to be the suitable plastic material for which red mud can be used as fillers. With the addition of red mud the plastic showed red brown color. As the ratio of amount of red mud to plastic increased, the tensile strength increased while the Izod impact strength decreased. About five percent of ethylene vinyl alcohol(EVA) was needed as an additive to prevent the lowering of impact strength. Maleic anhydride modified polypropylene was effective for reduction of impact strength lowering of PP. Mixed waste plastics containing LDPE, HDPE, PP, polystyrene and ABS could also accommodate red mud as fillers. In this case, significant loss in mechanical properties were observed due to immiscibility between the components. Ethylene propylene rubber(EPR) and styrene butadiene styrene block copolymer (SBS) could be used to improve the impact properties of the commingled waste plastics.