• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.886-889
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• 2001

Silicone rubber is being used for the housing material of outdoor high voltage insulators such as composite insulator, bushing, surge arrestor and cable terminator because of good tracking and erosion resistance, good hydrophobicity and recovery of hydrophobicity and chemical stability. But, the leakge current occurs on surface of the composite polymeric insulation materials when the insulator is used for a long time with severe contaminative condition and it can lead the contamination flashover. So the leakage current is important to estimate the condition of the silicone rubber surface. In this paper, aging characteristics of silicone rubber used for outdoor insulation have been hydrophobicity of silicone rubber in salt fog chamber with average leakage current monitoring for observing the transformation of surface degradation properties of silicone rubber with different ATH(alumina trihydrate, A1$_2$O$_3$$.$3H$_2$O) filler contents. The experimental results show that a higher peak leakage current and to raise a long time for tracking with increasing amount of ATH by the salt fog and heat recycle ageing.

• Elastomers and Composites
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• 제54권3호
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• pp.209-219
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• 2019

It is important to analyze crosslink densities of rubber articles because the physical properties are dependent on the crosslink densities. In this paper, analytical techniques for the measurement of crosslink densities of rubber vulcanizates are described. The most widely used method to measure the crosslink density is a swelling method combined with the Flory-Rehner equation. Application of the interaction parameter (${\chi}$) of rubber and swelling solvent is critical because the crosslink density is absolutely dependent on the ${\chi}$ value. Methods for obtaining ${\chi}$ employ not only solubility parameters of the polymer and swelling solvent but also inverse gas chromatography (IGC). The solubilities of rubbers can be obtained using micro differential scanning calorimetry (${\mu}DSC$), intrinsic viscosity measurement, and UV-visible spectroscopy. Nuclear magnetic resonance (NMR) spectroscopy has been also used for the measurement of the crosslink density using the $T_2$ relaxation time, which is determined by spin-spin relaxation in solid-state NMR. For sulfur-cured rubber vulcanizates, crosslink densities according to the crosslink types of mono-, di-, and polysulfides are measured by treating the rubber samples with a chemical probe composed of thiol and amine compounds. Measurement methods of physical crosslinking by filler, crystallization, and ionic bonding have also been introduced.

• Elastomers and Composites
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• 제54권1호
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• pp.22-29
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• 2019

Chitosan-polyvinyl alcohol (PVA) -bamboo charcoal/silica (CS-PVA-BC/SI) hybrid fillers with compatibilized styrene-butadiene rubber (SBR) composites were fabricated by the interpenetrating polymer network (IPN) method. The structure and composition of the composite samples were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). The viscoelastic behaviors of the rubber composites and their vulcanizates were explored using a rubber processing analyzer (RPA) in the rheometer, strain sweep and temperature sweep modes. The storage and loss moduli of SBR increased significantly with the incorporation of different hybrid fillers, which was attributed to the formation of an interphase between the hybrid fillers and rubber matrix, and the effective dispersion of the hybrid fillers. The mechanical properties (hardness, tensile strength, oxygen transmission rate, and swelling rate) of the composite samples were characterized in detail. From the results of the mechanical test, it was found that BC-CS-PVA0SBR had the best mechanical properties. Therefore, the BC-CS-PVA hybrid filler provided the best reinforcement effects for the SBR latex in this research.

• Elastomers and Composites
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• 제27권4호
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• pp.281-288
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• 1992

The purpose for this study is to examine the vulcanization characteristics, especially the damping, elastic modulus and viscous modulus properties of filler 50phr filled NR compounds and to find out the compounds which can be used as damping materials in industry. For this study, compounds were prepared with filler filled compounding formula. Their vulcanization characteristics, elastic modulus, viscous modulus and damping properties were examined by mean of the rheometrics dynamic spectrometer. The results of this study can be summarized as follows. 1. The elastic modulus values of the maxium under the condition of 1Hz frequency, showed the order as follows, $HAF>Silica>FEF>GPF>SRF>Clay>CaCO_3\;coated>CaCO_3$. 2. The damping values of the maxium under the condition of 1Hz frequency, showed the order as follows $Silica>HAF>FEF>GPF>SRF>Clay>CaCO_3\;coated>CaCO_3$.

• Elastomers and Composites
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• 제55권4호
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• pp.339-346
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• 2020

We functionalized a wear-resistant carbon-based MoS2 filler to solve its limited wear condition problem. The filler exhibits excellent lubricative properties. The surface modification of MoS2 was carried out using a (3-glycidyloxypropyl)trimethoxysilane (GPTMS) silane coupling agent to improve the low compatibility and dispersibility of the filler that generally degrade the performance of composites. A silane coupling agent was employed for the functionalization of MoS2, and its effect on the wear resistance of MoS2/Polyamide-6,6 was investigated. The silanization of MoS2 was identified by contact angle analysis and Fourier-transform infrared, energy dispersive X-ray, and X-ray photoelectron spectroscopies. The wear resistance of the composite was found to be improved significantly by the surface functionalization of MoS2.

• 폴리머
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• 제29권2호
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• pp.161-165
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• 2005

Octamethylcyclotetrasiloxane$(D_4)$과 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane$(D_3^{MePh})$을 1,1,3,3,-tetramethyl-1,3-divinylsiloxane(MVS)과 평형중합시켜 dimethylsiloxane과 methylphenylsiloxane block unit를 갖는 $\alpha,\omega-vinyl$ poly(dimethyl-methylphenyl)siloxane prepolymer(VPMPS)를 제조하였으며 또한 $D_4$와 1,3,5-trimethyl-1,3,5-trifluoropropylcyclotrisiloxane $(D_3^{M3,F3P})$을 1,1,3,3-tetramethyldisiloxane과 평형중합시켜 dimethylsiloxane과 methyltrifluoropropyl siloxane block unit를 갖는 $\alpha,\omega-hydrogen$ poly(dimethyl-methyltrifluoropropyl)siloxane prepolymer(HPDMFS)를 제조하였다. VPMPS, HPDMFS, 열전도 필터 및 촉매를 고속교반기에 가하고 $130^{\circ}C$에서 컴파운딩하여 저경도 poly(organosiloxane) rubber를 제조하였으며 이의 가교밀도는 $115^{\circ}C$에서 oscillation rheometer를 이용하여 측정하였다. 열전도성 충전제로 구상 알루미나를 Horsfield's packing model에 따라 평균입자경의 분포를 조절하여 제조한 composite TC-POXR-2의 열전도도가 1.13 W/mK, 그리고 TC-POXR-4가 1.19 W/mK였으며 이는 단일입자경을 갖는 충전제를 가하여 제조한 경우보다 높은 열전도성을 나타내었다.

• Elastomers and Composites
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• 제56권4호
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• pp.243-249
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• 2021

The demand for truck bus radial (TBR) tires with enhanced fuel efficiency and wear resistance have grown in recent years. In addition, as the issue of particulate matter and air pollution increases, efforts are being made to reduce the generation of particulate matter. In this study, we investigated the effect of varying the content of butadiene rubber (BR) on the properties of the rubber compounds and the amount of particulate matter in the TBR tire tread compound. Furthermore, we utilized carbon black in the NR/BR blend compounds owing to its excellent compatibility, and we used silica in the ENR-25/BR blend compounds because it can interact chemically with epoxide groups. The NR/BR blend compounds and the ENR-25/BR blend compounds were evaluated by varying their BR content between 20 phr and 30 phr. The results showed that the ENR-25/BR blend compounds had superior wear resistance than the NR/BR blend compounds. This was caused by the interaction between silica and ENR. In addition, it was confirmed that the increased wear resistance as the BR content increased. Furthermore, compared to the NR/BR blend compounds, ENR-25/BR blend compounds exhibited a lower tan 𝛿 value at 60℃ because silica was used as filler. This indicates a higher fuel efficiency. The measurement results for wear particulate matter showed that as increasing the BR content resulted in generation of less wear particulate matter. This was caused by the increased wear resistance. Moreover, the ENR-25/BR blend compounds with excellent filler-rubber interaction exhibited lower quantities of generated wear particulate matters as compared to the NR/BR blend compounds.

• 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.

• 공업화학
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• 제21권5호
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• pp.581-585
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• 2010

산업폐기물 중의 하나인 무기 금속화합물, Alnico를 1,3,5-trimethylcyclotrisilazane으로 표면 처리하여 충전제로 하고 EPDM에 maleic anhydride (MA)를 용융 중합법으로 그라프트시켜 제조한 말레화 EPDM과 ${\alpha},{\omega}$-bis(3-aminopropyl)polydimethylsiloxane을 공중합시켜 제조한 말레화 EPDM-polydimethylsiloxane공중합체(MEPDM-PDMS)와 EPDM 및 표면처리된 Alnico를 compounding하여 composite rubber를 제조하였다. EPDM/Alnico/MEPDM-PDMS 방진고무는 MEPDMPDMS와 EPDM을 중량비로 1 : 10으로 하고 또한 충전제의 함량을 EPDM에 대하여 25, 50 phrs로 그리고 개시제로 dicumyl peroxide (DCP)를 첨가하여 compounding시킨 다음 유압 고온 프레스로 가교시켜 제조하였다. 제조한 composite rubber의 열적특성을 측정한 결과 MEPDM-PDMS를 첨가하여 제조한 시료의 Tg가 EPDM만으로 제조한 고무보다 약간 낮은 $-33^{\circ}C$ 부근으로 나타났고 DMA의 측정결과 손실계수 tan ${\delta}$는 MEPDM-PDMS을 혼합한 경우가 더 크게 나타나는 것으로 보아 방진 특성이 우수함을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.117-120
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• 1998

It is analyzed the erosing process of the polymeric insulator for outdoor use with the inclined plane method. Materials used are the different type of silicone rubber, they have the content of filler and component each other. As the content of filler added to improve the tracking and erosion resistance. It has the difference of electrical performance and erosion rate. The dry-band arc is also the parameter of accelerating erosion, and appear in the form of leakage current, and the activities of leakage current has a close relationship with the surface hydrophobicity. In this paper, the erosion growth is observed by measuring the time from the voltage application to the whole breakdown, and the erosion depth. In addition, it is measured the hydrophobicity and leakage current to be a cause of erosion by the erosion steps, studied SEM, EDX for observing the transformation of surface structure by erosing.