• Elastomers and Composites
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• 제46권4호
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• pp.329-334
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• 2011

일반적으로 butyl 고무(IIR : isobutylene isoprene rubber)는 우수한 내기체투과성 및 저반발 탄성체로서 우수한 충격흡수성을 갖는다. 본 실험에서는 butyl고무에 EPDM(ethylene propylene diene monomer)을 기계적 혼련법으로 blend 혼련물을 제조하여 이들의 가교 거동, 물리적 성질 및 내오존성 등을 측정하였다. EPDM 고무량이 증가할수록 최적 가황시간이 단축되는 경향을 보였다. 기체투과속도 테스트에 의한 내기체투과성 측정 결과 butyl고무량이 50 wt% 이상일 경우에는 기체투과도가 현저히 감소하였다. 한편 butyl rubber/EPDM 블렌드의 경우에 EPDM의 함량이 25 wt.% 이상 함유될 경우 내오존성이 향상되어 50 pphm, $50^{\circ}C$, 120시간 조건에서도 아무런 표면변화가 없었다.

• Elastomers and Composites
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• 제33권3호
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• pp.149-158
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• 1998

폴리초산비닐 에멀젼 수지에 SBR 라텍스, 폴리우레탄 라텍스, 에폭시 라텍스를 각각 혼합하여 물리적 특성 및 기계적 특성을 조사하였다. 에폭시 수지의 상용성은 양호하였으며 건조도막은 투명하였다. 폴리우레탄과 SBR은 높은 점도를 나타내었으며 건조도막은 불투명하였다. SBR과 폴리우레탄 수지에서 경도의 증가는 물의 증발속도에 의존하였지만 에폭시 수지에서는 가교밀도의 증가에 의존하였다. 에폭시 수지는 매우 뛰어난 내수성을 나타내었다. SBR은 높은 굴곡강도와 충격강도를 나타내었다. 폴리초산비닐에 라텍스를 10% 이내로 혼합하였을 때에는 연성파괴를 나타내었고 20% 이상 혼합하였을 때에는 취성파괴를 나타내었다.

• Elastomers and Composites
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• 제47권1호
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• pp.30-35
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• 2012

새로운 스타폴리머인 바이오폴리부타디엔은 리빙 음이온중합이라는 고분자의 정밀 합성법을 통하여 분자량, 분자량분포, 조성 및 세부구조를 제어하였다. 리빙 음이온중합에 의해 n-BuLi으로 개시된 polybutadienyllithium(PBDLi)의 연쇄말단이 ESO(Epoxidized Soybean Oil)의 기능성 그룹과 커플링 반응을 일으키며 스타폴리머를 합성한다. 분자량이 1,000/5,000/10,000(g/mol)인 PBDLi을 중합하여 THF존재하에서 반응 후 GPC에 의한 분자량 및 arms분석과 $^1H$-NMR, FT-IR에 의한 고분자 구조 분석을 통하여 바이오폴리부타디엔의 합성을 확인하였다.

• Elastomers and Composites
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• 제16권1호
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• pp.3-13
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• 1981

The purpose of this dissertation is to study the physical properties of cellular rubber products for industrial use. Vulcanization characteristics were investigated by usingcure curve that had obtained by means of Rheometer. The results of physical properties, vulcanization characteristics and foaming states are as follows. 1. The test results for vulcanization characteristics of NR compounds indicated that in the recipe R-1. When accelerator D is used, the optimum conditions of vulcanizate are obtained, while formula R-2 and R-3 have shown higher torgue at curing time, $1{\sim}2$ minutes. Cellular rubber product test in terms of compression set and compression deflection has also met the requirements of SAE. 2. For SBR compounds, S-1 formula was the best in terns of vulcanization characteristics, and for the blowing structure of cellular rubber products, formula S-3 in which accelerator M is added was fair. All other test results, such as compression set and compression deflection properties met SAE requirements. 3. NBR compound (N-1) including accelerator TT was the best in terms of vulcanization characteristic and also blowing structure. All other properties listed above met requirements, particulary for oil resistance test. 4. In the test of EPDM compounds, when mixed accelerator, M and TT, is used(formula E-1) the best results were obtained. Since EPDM is hydrocarbon elastomer, oil resistance test failed. All other properties met the requirement specified in SAE.

• Elastomers and Composites
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• 제45권3호
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• pp.156-164
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• 2010

열가소성 탄성체(TPE)는 사용 온도 범위에서 일반 열경화성 고무와 같은 고무 탄성을 지니면서 용융 가공이 가능한 친환경 소재로써 산업 전반에 걸쳐 활용도가 꾸준히 증가하고 있다. 폴리아미드계 TPE (TPAE)는 하드세그멘트가 엔지니어링 플라스틱인 폴리아미드로 이루어져 있고, 소프트 세그먼트가 유리전이온도가 낮은 폴리에테르로 이루어진 다중 블록 공중합체로써 우수한 기계적 물성, 내화학성, 내열성 및 가공성을 나타낸다. 이러한 폴리아미드계 TPE는 하드 세그먼트와 소프트 세그먼트의 구조 및 상대적 조성에 따라 탄성체에서부터 연질 폴리아미드까지의 광범위한 특성이 발현되며, 또한, 다양한 무기 입자와의 하이브리드화를 통한 기능성 소재로의 활용이 기대되는 소재이다. 본 보문에서는 이러한 TPAE를 합성 할 수 있는 중합 방법과 특성 및 응용 분야에 대해 정리하였다.

• Elastomers and Composites
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• 제53권3호
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• pp.150-157
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• 2018

Fatigue properties of rubber are one of the most important characteristics in the rubber industry. In this study, the fatigue properties of MREs (magneto-rheological elastomers) based on NR (natural rubber), EPDM (ethylene-propylene diene monomer), and AEM (ethylene/acrylic elastomer) were investigated. For comparison, MREs with a Shore hardness of 60A were prepared. According to the relative results, the fatigue properties of EPDM MRE were the worst. Thus, we investigated methods to improve the fatigue properties of EPDM MRE by varying the carbon black content and curing systems of EPDM as the matrix of the MRE. Dynamic properties were measured using a fatigue tester and an RPA (rubber process analyzer), and the XPS (X-ray photoelectron spectroscopy) was used to analyze the curing system of the EPDM matrix. According to the results, the Payne effect increased and the fatigue resistance decreased as the carbon black content increased. In case of the curing system, the CV (conventional vulcanization) system was superior to the EV (efficient vulcanization) system in terms of the fatigue resistance. This was because the number of flexible bonds in the case of the CV system was higher than that in the case of the EV system. However, the EV system showed excellent mechanical properties because it had many monosulfidic bonds with strong binding energy.

• Elastomers and Composites
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• 제55권2호
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• pp.88-94
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• 2020

Automobile industry, along with the automobile steering system, is rapidly changing and developing. The constant velocity joint transmits power to the wheels of vehicles without changing their angular velocity based on the movement of the steering wheel. Moreover, it controls their movement to act as a buffer. In order to prevent the excessive increase in temperature caused by the movement of vehicles, boots are attached to the constant velocity joint and lubricant is injected into the boots. The boots maintain the lubrication and protect the constant velocity joint from sand, water, and so on. As the wheels of the vehicle rotate, the boots are acted upon by forces such as bending, compression, and tension. Additionally, self-contact occurs to boots. Therefore, their durability deteriorates over time. To prevent this problem, polychloroprene rubber was initially used however, it was replaced by thermoplastic polyester elastomers due to their excellent fatigue durability. In this study, the structural analysis of boots was conducted. The results showed the deformation patterns of the boots based on the translation and rotation of the constant velocity joint. Moreover, it confirmed the location that was vulnerable to deformation. This study can be used to potentially design high-quality constant velocity joint boots.

• Composites Research
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• 제32권5호
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• pp.211-215
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• 2019

정적인 상태인 체외 환경(in vitro)에서의 세포배양 과정은 실제 생체 내 환경에서의 세포발달과정과는 많은 차이가 존재한다. 따라서, 체내 환경의 정밀한 모사를 위해서는, 기계적인 자극을 세포에 전달하여 줄 수 있는 동적 세포배양장치가 필수적이다. 하지만 기존의 동적 세포배양장치에는 튜브, 펌프, 모터 등의 비교적 복잡한 장치들을 필요로 하였으며, 전달되는 기계적 자극도 단순한 형태였다. 본 연구에서는 단순한 장치로 구동되는 동적 세포배양장치를 위하여 전기활성고분자(EAP) 구동기를 동력원으로 하는 소형 동적 세포배양장치를 설계하였다. 이 장치는 다양한 기계적 자극을 세포에 전달하는 것이 가능하다.

• Elastomers and Composites
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• 제56권1호
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• pp.6-11
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• 2021

In order to develop an ultra-high-density elastomeric material for substitution of steel dynamic dampers, a new curing system and technique for high-loading of the filler were examined in this study. Mechanochemical modification of chloroprene rubber (MAH-g-CR) using an internal mixer was carried out with maleic anhydride (MAH) as a reactive monomer. The optimum amount of MAH was 10 phr and the efficient grafting of MAH on CR could be achieved at a mixing temperature of 100℃. After preparing MAH-g-CR, 50 mol% epoxidized natural rubber (ENR 50) was blended with MAH-g-CR to develop a "self-curable rubber blend system" via reaction between the functional groups of the elastomeric matrices without the curing agent and additives. The content of ENR 50 was fixed at 30 wt.% throughout evaluation of the curing behavior of the MAH-g-CR/ENR blend. Tungsten powder was added to the MAH-g-CR/ENR matrix up to 60 vol.% to obtain ultra-high-density, and the maximum density obtained was 7.57 g/㎤. Stable ts2 (scorch time) and t90 (90% cure time) could be obtained even when tungsten powder was incorporated up to 60 vol.%. In addition, the tensile strength and damping properties of MAH-g-CR/ENR containing 60 vol.% of tungsten were better than those of CR containing 60 vol.% of tungsten.

• Elastomers and Composites
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• 제34권2호
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• pp.177-182
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• 1999

SBS thermoplastic elastomers offer an inexpensive alternative to vulcanised rubbers for many undemanding applications. They are, however, particularly susceptible to attack from atmospheric ozone leading to cracking as soon as any strain is applied. In most rubber applications some strain is unavoidable. In this paper a compounding approach to protecting SBS thermoplastic rubbers against ozone is described. An explanation is offered for why a protective effect Is observed only when certain combinations of additive are used. SBS elastomers are the most affordable class of thermoplastic rubbers. To achieve finished products resistant to ozone and without compromising the light colours often demanded, recourse must be made to blending with other saturated elastomers or replacement by hydrogenated (SEBS) types. The latter is a significantly more expensive alternative. Under laboratory conditions where the rate of ozone attack is increased by several decades, unprotected SBS begins to crack within a few hours. Several different protective agents are examined here, the best of which, a cyclic enol ether, $Vulkazon^{(R)}$ AFD, can extend the resistance to any cracking to several weeks by the use of a few percent by weight of additive. The systems reported neither discolour the polymer nor stain other materials with which it may be in contact. Use of the protective systems described here could enable SBS elastomers to compete in many applications with the more expensive SEBS polymers.