• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1744-1748
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• 2007

In this study, the Johnson-Kendall-Roberts (JKR) theory was combined with the instrumented indentation technique (IIT) to evaluate work of adhesion and modulus of elastomeric polymer. Indentation test was used to obtain the load-displacement data for contacts between Tungsten Carbide indenter and elastomeric polymer. And the JKR contact model, contrived to take viscoelastic effects of polymer into account, was applied to compensate the contact area and the elastic modulus which Hertzian contact model would underestimate and overestimate, respectively. Besides, we could obtain the thermodynamic work of adhesion by considering the surface energy in this contact model. In order to define the relation between JKR contact area and applied load without optical measuring of contact area, we used the relation between applied load and contact stiffness by examining the correlation between JKR contact area and stiffness through dimensional analysis with 14 kinds of elastomeric polymer. From this work, it could be demonstrated that the interfacial work of adhesion and elastic modulus of compliant polymer can be obtained from a simple instrumented indentation testing without area measurement, and provided as the main algorithm of compliant polymer characterization.

• 대한기계학회논문집A
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• 제31권9호
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• pp.951-959
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• 2007

In this study, the Johnson-Kendall-Roberts(JKR) theory was combined with the instrumented indentation technique (IIT) to evaluate work of adhesion and modulus of elastomeric polymer. Indentation test was used to obtain the load-displacement data for contacts between Tungsten Carbide indenter and elastomeric polymer. And the JKR contact model, contrived to take viscoelastic effects of polymer into account, was applied to compensate the contact area and the elastic modulus which Hertzian contact model would underestimate and overestimate, respectively. Besides, we could obtain the thermodynamic work of adhesion by considering the surface energy in this contact model. In order to define the relation between JKR contact area and applied load without optical measuring of contact area, we used the relation between applied load and contact stiffness by examining the correlation between JKR contact area and stiffness through dimensional analysis with 14 kinds of elastomeric polymer. From this work, it could be demonstrated that the interfacial work of adhesion and elastic modulus of compliant polymer can be obtained from a simple instrumented indentation testing without area measurement, and provided as the main algorithm of compliant polymer characterization.

• 한국고분자학회지:고분자과학과기술
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• 제7권1호
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• pp.23-34
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• 1996

• Elastomers and Composites
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• 제58권3호
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• pp.142-151
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• 2023

In this study, we investigate the thermal and mechanical properties of composites comprising ethylene propylene diene monomer (EPDM) and polybutadiene (PB) obtained using carbon black (CB) as a reinforcing and compatibilizing filler. Owing to the significance of elastomeric materials in various industrial applications, blending of EPDM and PB has emerged as a strategic method to optimize the material properties for specific applications. This study offers insights into the blend composition, its microstructure, and the resulting macroscopic behaviors, focusing on the synergetic effects of composite materials. Furthermore, this study delves into curing and rheological behaviors, crosslink densities, and mechanical, thermal, and elastic properties of the elastomeric composites. Through systematic exploration, we believe that this study will be beneficial to material scientists and engineers working on developing advanced elastomeric composites.

• Macromolecular Research
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• 제10권2호
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• pp.54-59
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• 2002

ABA triblock copolymers of L-lactide and trimethylene carbonate with several different compositions were prepared by sequential ring-opening polymerization in the presence of diethylene glycol. Also chain-extension reactions of the resulting copolymers were carried out using hexamethylene diisocyanate to produce relatively high molecular weight polymers, which could be cast into elastomeric tough films. The polymers with certain L-lactide contents were partially crystalline, exhibiting two-phase morphology. The polymer films showed reversible elastic behavior under tensile tension, providing a novel thermoplastic elastomer possessing desirable properties such as biodegradability and good mechanical properties.

• 전기학회논문지
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• 제67권6호
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• pp.799-803
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• 2018

We demonstrated memory thin-film transistors (MTFTs) with organic ferroelectric polymer poly(vinylidene fluoride-co-trifluoroethylene) and an amorphous oxide semiconducting indium gallium zinc oxide channel on the elastomeric substrate. The dielectric constant for the P(VDF-TrFE) thin film prepared on the elastomeric substrate was calculated to be 10 at a high frequency of 1 MHz. The voltage-dependent capacitance variations showed typical butterfly-shaped hysteresis behaviors owing to the polarization reversal in the film. The carrier mobility and memory on/off ratio of the MTFTs showed $15cm^2V^{-1}s^{-1}$ and $10^6$, respectively. This result indicates that the P(VDF-TrFE) film prepared on the elastomeric substrate exhibits ferroelectric natures. The fabricated MTFTs exhibited sufficiently encouraging device characteristics even on the elastomeric substrate to realize mechanically stretchable nonvolatile memory devices.

• Journal of the Optical Society of Korea
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• 제15권4호
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• pp.329-334
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• 2011

We proposed a poly-dimethylsiloxane (PDMS)-coated fiber Bragg grating (FBG) temperature sensor for enhancing temperature sensitivity. By embedding the bare FBG in a temperature-sensitive elastomeric polymer, the temperature sensitivity of the proposed structure could be effectively improved by 4.2 times higher than those of the conventional bare-type FBG sensors due to the high thermal expansion coefficient of the PDMS. We analyzed the temperature-sensitivity enhancement effect with the increased Bragg wavelength shift in our structure and dependence on the temperature sensitivity with respect to the cross-section area of the PDMS.

• Structural Engineering and Mechanics
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• 제53권3호
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• pp.497-517
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• 2015

In this study, nonlocal nonlinear buckling analysis of embedded polymeric temperature-dependent microplates resting on an elastic matrix as orthotropic temperature-dependent elastomeric medium is investigated. The microplate is reinforced by single-walled carbon nanotubes (SWCNTs) in which the equivalent material properties nanocomposite are estimated based on the rule of mixture. For the carbon-nanotube reinforced composite (CNTRC) plate, both cases of uniform distribution (UD) and functionally graded (FG) distribution patterns of SWCNT reinforcements are considered. The small size effects of microplate are considered based on Eringen's nonlocal theory. Based on orthotropic Mindlin plate theory along with von K$\acute{a}$rm$\acute{a}$n geometric nonlinearity and Hamilton's principle, the governing equations are derived. Generalized differential quadrature method (GDQM) is applied for obtaining the buckling load of system. The effects of different parameters such as nonlocal parameters, volume fractions of SWCNTs, distribution type of SWCNTs in polymer, elastomeric medium, aspect ratio, boundary condition, orientation of foundation orthtotropy direction and temperature are considered on the nonlinear buckling of the microplate. Results indicate that CNT distribution close to top and bottom are more efficient than those distributed nearby the mid-plane for increasing the buckling load.

• Elastomers and Composites
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• 제40권2호
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• pp.93-103
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• 2005

본 연구에서는 자동차에서 댐핑 재료로 많이 사용되고 있는 스틸 다이내믹 댐퍼를 대체할 수 있는 소재로서 유기탄성체를 사용하였다. 그러나 유기탄성체를 사용하여 스틸 다이내믹 댐퍼를 대체하기 위해서는 스틸 다이내믹 댐퍼에 상응하는 비중의 구현이 가장 중요하고도 해결하기 어려운 과제이다. 본 연구에서는 고비중 구현을 위한 첫 단계로 최적의 매트릭스 탄성체 및 충전제를 선정하여 충전제의 충전량(vol%)에 따른 고무 혼합물의 경화 특성, 인장 강도, 혼련과정중의 고무 혼합물의 온도 변화 및 반발 탄성 등의 특성을 조사하였다. 충전량이 증가할수록 고무 혼합물의 $t_{s2}$는 감소하였고 $t_{90}$는 전반적으로 증가하였다. 또한 인장 강도는 감소하였고 고무 혼합물의 온도는 충전제 입자간의 마찰열로 인하여 증가하였다. 반발탄성은 충전제가 증가할수록 감소하였다. 따라서 초 고비중을 얻기 위해서는 고충전 기술이 선결되어야 하는데 고충전을 할 경우 매트릭스인 유기탄성체의 부피가 상대적으로 감소하기 때문에 기존의 유기탄성체 경화 시스템으로는 경화가 불가능하여 고충전에 부합하는 경화 시스템을 구축 하고자 매트릭스의 광화학적 개질을 시도하였고, 개질여부는 FTIR-ATR로 분석을 통해 확인하였다. 충전제의 충전밀도를 높여 매트릭스 탄성체에 충전제의 안정한 분산 및 고충전 기술을 확립하고자 충전제의 개질을 통해 충전제의 입도, 입도 분포도 및 형태를 제어하였다. 입도분석기로 입도 및 입도 분포의 변화를 확인하였고 SEM을 이용하여 충전제의 형태 변화를 확인하였다.

• Elastomers and Composites
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• 제46권1호
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• pp.2-9
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• 2011

가스와 증기에 대한 투과성(Permeability to gases and Vapors)은 고무 제품을 타이어 튜브나 다이아후램(diaphragm)과 같은 제품으로 사용하고자 할 때 아주 중요한 특성이다. 모든 고무는 가스와 증기에 대하여 투과성이 있다. 그러나 그 투과 속도는 고무 재질에 따라 아주 다르다. 일반적으로 실리콘 고무의 투과성이 제일 크고, 그 다음으로 NR, EPDM, SBR, CR, NBR, FPM, ECO, IIR 순이다. 이러한 투과성은 같은 원료고무를 사용해도 사용 배합약품의 종류에 따라 크게 다를 수도 있다. 고무와 기체와의 메커니즘은 발포고무에 매우 중요하게 되어 이에 대한 연구$^{1-7}$는 많이 이루어졌으나 고무의 차단성에 대한 연구는 그리 많지 않다. 고무소재의 투과성 또는 차단성 기능을 주기위하여 나노복합탄성체$^8$의 기술 동향 및 코팅에 의한 기능성 향상$^{9-13}$을 하거나 열가소성탄성체 본문에서 적용하는 기술이 있는데 자동차에 사용되는 액체 및 기체 차단용 고무부품에 대하여 몇가지 소개하여 본다.