• Elastomers and Composites
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• 제56권4호
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• pp.201-208
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• 2021

In this study, the effect of petroleum resin on the mechanical strength, morphology, and vibration damping characteristics of natural rubber (NR) composites was observed. The NR composites plasticized by adding petroleum resin showed decreased hardness and mechanical properties. A morphology analysis indicated that as the amount of petroleum resin increased, carbon black aggregates (or agglomerates) observed at the fracture surface decreased, resulting in an improvement in the dispersibility. In addition, as 20 phr of petroleum resin was added, the effective damping temperature range increased by approximately 11.4%, the hysteresis loss rate increased by 15.2%, and the resilience decreased by 36.6%. Therefore, it was confirmed that the vibration damping characteristics improved with the addition of petroleum resin. This was because the rubber-filler interaction between the NR molecular chain of the NR composite and the carbon black particles improved by the addition of petroleum resin.

• Elastomers and Composites
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• 제42권2호
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• pp.107-111
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• 2007

초기 상태를 선가황 혹은 미가황으로 다르게 한 NR과 BR 복합체 간의 접착에 대해 연구하였다. 동일한 고무인 NR/NR과 BR/BR 간의 접착뿐 아니라 이종 고무 간의 접착인 NR/BR의 접착도 조사하였다. 미가황 시트 간의 접착력이 선가황/미가황 시험편과 선가황/선가황 시험 편보다 우수하였다. 선가황/선가황 시험편과 미가황 NR/선가황 BR시험편은 완전 박리가 일어났다. 박리 시험 중 파단이 일어난 경우, 고무의 종류에 상관없이 두 개의 시트 중에 가교밀도가 높은 곳에서 끊어졌다. 이종 고무 간의 접착력보다는 동종 간의 접착력이 더 우수하였으며, 선가황 NR/미가황 BR의 접착력이 미가황 NR/선가황 BR의 경우보다 더 컸다. 실험 결과는 가교밀도와 고무 사슬의 계면간 확산으로 설명하였다.

• Elastomers and Composites
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• 제46권3호
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• pp.237-244
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• 2011

비보강, 카본블랙, 카본블랙과 실란커플링제, 실리카, 실리카와 실란커플링제 등 5가지의 다른 충전 시스템을 갖는 NR 복합체를 열노화시켰으며, 가속 열노화에 의한 가교밀도 변화를 연구하였다. 가교밀도는 충전 시스템과 관계없이 노화 시간이 경과함에 따라 증가하였다. 노화 온도가 높아질수록 가교밀도는 눈에 띄게 변하였다. 카본블랙으 로 보강된 NR 복합체의 경우, 실란커플링제는 가교밀도를 증가시켰다. 하지만 실리카로 보강된 NR 복합체의 경우에는 $60^{\circ}C$와 $70^{\circ}C$ 노화에서는 가교밀도 증가분이 감소하였으며, $80^{\circ}C$와 $90^{\circ}C$에서는 거의 영향을 주지 않았다. 카본블랙으로 보강된 NR 복합체의 가교밀도 변화에 대한 활성화 에너지는 로그 함수 형태로 지속적으로 증가한 반면, 실리카로 보강된 NR 복합체의 경우에는 노화 시간 30-150일 구간에서는 거의 변화가 없었다. 비보강 시험편의 활성화 에너지 는 노화 시간에 따라 지수 함수 형태로 증가하였다. 실험 결과는 실란커플링제로부터의 황 제공, 실란커플링제에 의한 충전제의 표면 개질, 실리카 표면에서의 가교제 잔류물의 흡착, 그리고 흡착된 가교제 잔류물의 방출 등으로 설명하였다.

• Elastomers and Composites
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• 제23권4호
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• pp.308-323
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• 1988

• Elastomers and Composites
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• 제57권4호
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• pp.188-196
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• 2022

Styrene-butadiene rubber(SBR) is a copolymer of styrene and butadiene. It is composed of 1,2-unit, 1,4-unit, and styrene, and its properties are dependent on its microstructure. In general, rubber composites contain a single rubber or a blended rubber. Similarly, SBR is used by mixing with natural rubber(NR) and butadiene rubber(BR). The composition of a rubber article affects its physical and chemical properties. Herein, an analytical method for determining the microstructure of SBR using via pyrolysis is introduced. Pyrolysis-gas chromatography/mass spectrometry is widely used to analyze the microstructure of polymeric materials. The microstructure of SBR can be determined by analyzing the principal pyrolysis products formed from SBR, such as 4-vinylcyclohexene, styrene, 2-phenylpropene, 3-phenylcyclopentene, and 4-phenylcyclohexene. An analytical method for determining the composition of SBR/NR, SBR/BR, and SBR/NR/BR blends via pyrolysis is introduced. The composition of blended rubber can be determined by analyzing the principal pyrolysis products formed from each rubber component.

• Environmental Engineering Research
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• 제20권4호
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• pp.342-346
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• 2015

Haloacetonitriles (HANs) are nitrogenous disinfection by-products (DBPs) that have been reported to have a higher toxicity than the other groups of DBPs. The adsorption process is mostly used to remove HANs in aqueous solutions. Functionalized composite materials tend to be effective adsorbents due to their hydrophobicity and specific adsorptive mechanism. In this study, the removal of dichloroacetonitrile (DCAN) from tap water by adsorption on thiol-functionalized mesoporous composites made from natural rubber (NR) and hexagonal mesoporous silica (HMS-SH) was investigated. Fourier-transform infrared spectroscopy (FTIR) results revealed that the thiol group of NR/HMS was covered with NR molecules. X-ray diffraction (XRD) analysis indicated an expansion of the hexagonal unit cell. Adsorption kinetic and isotherm models were used to determine the adsorption mechanisms and the experiments revealed that NR/HMS-SH had a higher DCAN adsorption capacity than powered activated carbon (PAC). NR/HMS-SH adsorption reached equilibrium after 12 hours and its adsorption kinetics fit well with a pseudo-second-order model. A linear model was found to fit well with the DCAN adsorption isotherm at a low concentration level.

• Elastomers and Composites
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• 제39권1호
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• pp.51-60
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• 2004

본 연구에서는 organoclay를 혼합한 NR/BR blend의 가황특성, 동적점탄성 및 기계적 물성을 carbon black 및 silica를 함유한 배합고무와 비교 평가하였다. Solution 혼합법을 이용함으로써 광범위한 나노 복합체를 제조할 수 있었으며, 충전제의 함량은 10phr로 고정하였다. XRD 실험으로 clay의 삽입 및 박리정도를 측정하였다. 통상적인 혼합법을 이용할 경우 clay의 박리 또는 삽입정도가 미약한 반면 solution 혼합법을 이용할 경우 광범위한 박리형태의 clay 배합고무를 얻을 수 있음을 확인하였다. Clay 배합고무는 carbon black 및 silica를 함유한 배합고무에 비해 높은 tan ${\delta}$값을 나타내며, solution 혼합법을 이용할 경우 통상적인 혼합법에 의해 제조된 clay 배합고무에 비해 우수한 기계적 물성을 가짐을 확인할 수 있었다.

• Elastomers and Composites
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• 제53권2호
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• pp.67-74
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• 2018

Magneto-rheological elastomers (MREs) are smart materials in which the inherent stiffness and damping properties can be changed by the influence of an external magnetic field. The magneto-rheological (MR) effect depends on the orientation characteristics of the dispersed magneto-responsible particles (MRPs) in the matrix. In this study, natural rubber (NR) and ethylene propylene diene rubber (EPDM) were blended and used as a matrix of an MRE. EPDM was pre-cured before blending with NR. The Mooney viscosity, curing characteristics, and mechanical properties were analyzed with various pre-curing conditions of EPDM and the NR/EPDM blend. The results show that excellent mechanical properties of the NR/EPDM blend-based MRE were obtained when the pre-curing time of EPDM was 60 min. The aging property of the NR-based MRE was improved by the introduction of pre-cured EPDM. Also, the anisotropic MRE showed a higher MR effect than that of the isotropic MRE.

• Elastomers and Composites
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• 제27권3호
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• pp.183-193
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• 1992

Compared with NR and HNBR compounds, the blend properties of NR/HNBR were studied. The heat, oil and ozone resistance of NR compounds were improved by blending HNBR, and these effects were more clearly revealed with elevating temperatures. For the overall stabilities of the compounds, it was resonable to use the carbon black under the 60phr. In the EV systems, high-saturated NR/HNBR and HNBR compounds showed similar total crosslink density in comparison with NR compounds. Interaction parameters calculated by stress-strain method showed widely varied value.

• Elastomers and Composites
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• 제29권2호
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• pp.121-130
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• 1994

The physical properties of rubber blend between natural rubber(NR) and ethylene propylene diene terpolymer(EPDM) were investigated as a study of EPDM composite materials. For EPDM/NR blends, the effects of ethylene and diene contents in EPDM, blend ratio, dicumyl peroxide(DCP) curing system on the physical properties, interfacial adhesion force and dynamic crack growth etc. were studied. EPDM/NR blends loaded with carbon black were prepared by mechanical mixing and cured by plate heating cure press. Crosslinking density was measured by swelling method with toluene. The physical properties of all blends were measured with Instron, fatigue to failure(FTF), Demattia flex cracking tester(DMFC), scanning electron microscopy (SEM), etc. As the ethylene and diene contents in EPDM increased, the physical properties, such as dynamic crack growth, adhesion to other component were increased too. Interfacial adhesion force of EPDM/NR blends to dissimilar layer was improved by the use of optimum peroxide curing system.