• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.149-154
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• 2011

In order to explore properties of various rubber compounds after thermal aging under the condition similar to the operating environment of a fuel cell-stack, heat resistance and compression set of those compounds were investigated for a long term operation in $H_2SO_4$, $H_2O$, and LLC (ethylene glycol : $H_2O=50:50$) solution. It was assumed that aging Acrylonitrile butadiene rubber (NBR) and Elthylene Propylene diene rubber (EDPM) compound in the solution resulted in discoloration as time passed. It was also found that hydrolysis was developed on the Silicone rubber (VMQ) compound intentionally aged under acidic condition by means of TGA, SEM, and EDS analysis.

• Elastomers and Composites
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• v.32 no.3
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• pp.157-165
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• 1997

The morphology of the thermoplastic vulcanizates prepared from ethylene-propylene-diene terpolymer, polypropylene and high density polyethylene(HDPE) or ethylene based ionomer were studied. Blends were prepared in a laboratory internal mixer where EPDM was cured in the presence of PP and HDPE or ionomer under shear with dicumyl peroxide(DCP). The effects of DCP concentration and rubber/plastics composition were studied. In the morphological analysis by scanning electron microscopy (SEM), a small amount of EPDM acted as a compatibilizer to HDPE and PP. It was also revealed that the dynamic vulcanization process could reduce the domain size of the crosslinked EPDM phase. When ionomer was added to EPDM/PP blend, the thermoplastic vulcanizate showed typical ductile fracture topology and the trend was more clearly observed when DCP contents and ionomer contents are higher.

• Elastomers and Composites
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• v.49 no.3
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• pp.181-190
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• 2014

Melt grafting of itaconic acid (IA) onto an ethylene-propylene-diene terpolymer (EPDM) with various organic peroxide initiators was performed. Finding the optimum mixing conditions and concentration of ingredients is critical for effective grafting and optimum properties of grafted materials. This study focused on the effects of mixing conditions (temperature and time), initiator type/concentration and monomer concentration on the grafting degree and efficiency, melt flow index, and gel content of EPDM-g-IA. The initiator, 2,5-dimethyl-2,5-di(tert-butyl peroxy)-hexane (T-101), appeared to meet for the best grafting degree (1.91%). The grafting degree increased markedly by increasing the amounts of monomer IA and initiator T-101. The grafting degree also increased by increasing mixing temperature and time. The optimum monomer and initiator concentrations and reaction temperature and time were found to be about 5wt%/0.05wt% and $160^{\circ}C$/15min, respectively. It was found that the physical properties of EPDM-g-IA were higher than those of the pristine EPDM.

• Elastomers and Composites
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• v.48 no.1
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• pp.39-45
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• 2013

Melt grafting of citraconic acid (CCA) onto an ethylene-propylene-diene terpolymer (EPDM) with various peroxide initiators was performed using a Haake Rheocorder. Finding the optimum running condition and concentration is critical for effective grafting and performance of grafted material. Therefore, this study focused on the effects of mixing (reaction) condition and monomer/initiator dosages on the grafting degree, grafting efficiency and crosslinking degree (gel content), melt flow index and mechanical properties of CCA-g-EPDM. As the grafting degree/crosslinking degrees increased, the tensile strength increased significantly, but elongation at break and melt flow index decreased. The initiator 2,5-dimethyl-2,5-di(tert-butyl peroxy)-hexane (T-101) appeared to meet for the best grafting(2.31%). The grafting degree increased markedly with increasing monomer CCA/initiator T-101 contents. The grafting degree also increased with increasing mixing temperature/time, and then leveled off or decreased/increased a little. The optimum monomer/initiator dosages and reaction temperature/time were found to be about 5/0.05 wt% and $180^{\circ}C$/15min, respectively.

• Elastomers and Composites
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• v.37 no.2
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• pp.79-85
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• 2002

Ethyl-branched polyethylene [PE(2)] containing 2mole% ethyl branch and three ethylene-propylene rubbers (EPR's) having the same ethylene(E)-propylene(P) molar ratio(E/P=50/50) with different stereoregularity, that is, random EPR (r-EPR), alternating-EPR (alt-EPR) and isotactic-alternating-EPR (iso-alt-EPR) were mixed for the investigation or their properties depending on the stereoregularity. Crystallinity of the prepared blends decreased with increasing content of amorphous EPR because of a decrease in both the degree of annealing and kinetics of diffusion of the crystallizable polymer content. With blend composition, crystallinity was reduced with the stereoregularity in EPR. The thermodynamic interaction parameter(x) for the three blend systems approximately equals to zero near the melting point. These systems were determined to be miscible on a molecular scale near or above the crystalline melting point or the crystalline PE(2). From the measurement of $T_m$ vs. $T_c$, the behavior of PE(2) is mainly due to a diluent effect of EPR component. The spherulite size measured by small angle light scattering (SALS) technique depended upon blend composition, and stereoregularity of EPR. The size of spherulite was enlarged with the content of rubbery EPR and the decrease of stereoregularity in EPR.

• Elastomers and Composites
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• v.54 no.3
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• pp.220-224
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• 2019

Herein, three polymer compounds were manufactured using three polymer combination methods, ethylene-vinyl acetate/ethylene-propylene-diene-copolymer (EPDM), ethylene-vinyl acetate (EVA)/polyethylene-A (PE-A; density: 0.870), and ethylene-vinyl acetate (EVA)/polyethylene-B (PE-B; density: 0.885), for making cable sheath for use in the shipping industry. In this study, EVA, EPDM, PE-A, and PE-B were used as matrix polymers, and EVA-grafted maleic anhydride was used as a coupling agent for compounding with various compounds such as a fire retardant, cross-linking agent, filler, and other additives, besides the plasticizer. ${\Delta}T$, Mooney viscosity, and tensile strength increased in order of EPDM < PE-A < PE-B, the probable reason is due to the different crosslinking effect. The three compounds showed similar results for fire resistance and aging resistance after compounding process, but they showed excellent cold resistance owing to the non-polarity of the polymers and sufficient plasticizer content.

• 전기의세계
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• v.34 no.8
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• pp.476-488
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• 1985

전기공학분야의 여러다른 부분과 같이 전력케이블 분야에서도 수많은 연구와 아울러 특히 19세기후반에 전력케이블의 제작에 성공한 것은 20세기에 들어와서 케이블과 이에 관련된 모든 기술이 빠른 속도로 발달하게된 주원동력이 되었다고 보아도 과언은 아니다. 비록 19세기 후반에 고무(rubber)를 사용하여 케이블 절연 하였지만, 그이후 약 70여년이상을 Impergnated paper(오일복합수지(oil compound resin)나 오일(oil)을 종이에 스며들게한 후 그 종이를 절연재료로 이용함)를 전력케이블 절연재료로 많이 사용하여 왔다. 아울러 OF cable의 제조기술도 향상되어 현재 매우 높은 전압과 상당한 전력용량를 충족시키는 전력케이블로서 발달을 계속하고 있다. 1960년대에 들어서서 extruded polymer material 이 전력케이블의 절연재료로 쓰이게 되었는데 현저하게 주로 쓰이는 재료로 폴리에틸렌인대, 그대로 순수한 상태로 또는 어떤 처리를 하여 쓰기도 한다. 그러나 EPR(ethylene propylene rubber)도 역시 개발중에 있다. Extruded synthetic insulation을 사용한 케이블은 현재 모든 필요한 전류와 전압을 망라하여 널리 쓰이고 있으며 다른재료를 사용한 케이블 보다 설치하기에 쉽고 사용법이 비교적 간단하고, 또한 전력망(network)에서의 신뢰서이도 높은 것으로 나타나 매우 만족스런 재료로 인정받고 있다.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1537-1539
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• 2001

The radiation degradation of five insulating materials such as silicone rubber, ethylene-propylene rubber polybutylene terephthalte, poly carbonate, nylon 66 were evaluated by using thermogravimetry analysis (TGA) and tensile properties as a function of radiation doses. The results of temperature at 5% weight loss and activation energy from TGA showed linearly decreasing and increasing tendency as radiation doses comparing with tensile properties. Consequently, the assessment of TGA for the radiation degradation of materials was effective.

• Elastomers and Composites
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• v.25 no.2
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• pp.103-111
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• 1990

The blends of ethylene-propylene-diene terpolymer (EPDM) and high density polyethylene (HDPE) have been studied. Blends were prepared in a laboratory internal mixer, where EPDM was cured under shear with dicumyl peroxide (DCP) in the absence of HDPE and later blended with HDPE (cure-blend). The effect of DCP concentration, shear intensity of the mixing, and rubber/plastic composition were studied on the rheological, thermal and physical properties of the cure-blend. The results obtained were compared with those from blend-cure of Lee and Kim's work and discussed.

• Elastomers and Composites
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• v.55 no.1
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• pp.40-45
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• 2020

In this study, the mechanical and flame-retardant properties of ethylene-propylene-diene-termonomer (EPDM) based rubber compounds and various other environmentally friendly inorganic flame retardants were investigated. Alumina trihydrate (ATH) and magnesium hydroxide (MDH) were used as inorganic flame retardants. The mechanical properties after thermal oxidation aging and the flame-retardant properties of the EPDM compounds were measured using a moving die rheometer, a universal testing machine, a compression set, and a UL 94 V flammability test. We focused on how the properties were affected by the type and amount of flame retardants. The results demonstrated that the optimal mechanical and flame-retardant V-0 grade properties were obtained at an ATH content of 200 phr.