• Title, Summary, Keyword: FKM

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The Characteristics and Application of Virgin FKM Rubber/Recycled FKM Rubber Blend (재생 FKM Rubber/신재 FKM Rubber 블렌드의 특성 및 응용)

  • Park, Hyun-Ho;Lee, Chang-Seop
    • Elastomers and Composites
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    • v.40 no.2
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    • pp.104-111
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    • 2005
  • Virgin fluororubber(FKM) that is one of the highly-functionalized and expensive special rubber, and recycled FKM that is crushed by high temperature shear-crushing technique from recycled FKM were blended with the various mixing ratio to rubber blends. The cure characteristics and physical properties of these blended rubber compounds were investigated with various contents of recycled FKM and physical properties fur heat and fuels were also measured. Recycled FKM which is prepared by high temperature shear-crushing technique were blended to virgin FKM with the range of $0{\sim}50$ phr. The physical properties indicated that the rubber blend of recycled FKM with 30 phr turned out to be the best compound showing good dispersibility, heat resistance and fuel resistance and inexpensive in price.

Gas Permeation Study of Fuel Hose Composed as Inner Material of FKM Rubber (FKM 고무를 내층재료로 한 연료호스의 가스 투과성 연구)

  • Kim, Do-Hyun;Doh, Kyung-Hwan;Park, Hyun-Ho;Lee, Chang-Seop
    • Elastomers and Composites
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    • v.40 no.2
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    • pp.83-92
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    • 2005
  • To develop an automotive fuel hose suitable to the international environmental regulation, FKM rubber materials as an inner material of fuel hole were prepared with different chemical compositions. Measurement of the properties of thermal resistance, oil resistance, fuel resistance, gas permeability including fundamental properties were performed to investigate compatibility for a fuel hose material. Fundamental properties, thermal resistance, oil resistance, fuel resistance and permeability of FKM rubber materials were improved with fluorine content. When the carbon content was 20 phr, FKM compounds with fluorine contents of 66%, 09% and 71% were shown to satisfy the specification oi fuel hose. The gas permeability of NBR and FKM compounds was measured on the mixed fuel oils prepared with isooctane-toluene and gasoline-methanol. FKM rubber materials showed a small difference in penetrated amount of fuel and showed a permeability superior to NBR material. he permeability of FKM rubber materials was not influenced by the contents of fuel oil. Thermal properties of 69% FKM rubber experienced by permeability testing were not variated.

Characteristics and Properties of Fluoro/Silicone Rubber Blend System (불소/실리콘 고무 블렌드의 특성과 물성)

  • Lee, Jin-Kook;Song, Hwan-Jae;Kim, Mi-Ra
    • Journal of Adhesion and Interface
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    • v.9 no.3
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    • pp.14-19
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    • 2008
  • In this study, silicone rubber (SR40) and fluororubber (FKM) mixture blends were prepared by various weight percentages, and their properties were characterized. The crosslinking rate increased as the contents of SR40 due to the crosslinking agent in SR40. As contents of FKM increase in SR40/FKM blends, thermal decomposition temperature of blends increased. When SR40/FKM blend ratio was at 50/50, the thermal decomposition stabilization was higher than that of pure SR40. The contact angle of SR40/FKM blend increased as the increase of SR40 contents in blend. All composition of SR40/FKM blends showed typical phase separation morphology. As the contents of SR40 increase in SR40/FKM blend, the degree of separation in SR40/FKM blends also increased.

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Study on the Degradation Mechanism of FKM O-ring by X-ray Photoelectron Spectroscopy (X-ray Photoelectron Spectroscopy(XPS) 분석법을 이용한 FKM 오링의 노화 메카니즘 분석 연구)

  • Lee, Jin Hyok;Bae, Jong Woo;Yoon, Yu Mi;Choi, Myung Chan;Jo, Nam-ju
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.168-171
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    • 2017
  • In this study, we observed degradation mechanism of FKM O-ring by X-ray photoelectron spectroscopy(XPS) at atmosphere condition. FKM O-ring had 3.53mm of cross-sectional diameter and 91.67mm of inner diameter. After thermal degradation, oxygen atom concentration of FKM O-ring was increased to 20.39%, and fluorine atom concentration was decreased to 8.29%. We observed that degradation reaction occurred by oxidation reaction. By C1s and F1s peak analysis, we confirmed that oxidation reaction usually occurred at C-F bonding of FKM main chain. Also, carboxyl group(C-OH, C=O, O=C-O) produced by oxidation reaction from O1s peak analysis.

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The Study on the Pressure-Sensitive Adhesion Property of Waste FKM Powder and SBS Modified Asphalt (폐불소고무 분말과 SBS로 개질된 아스팔트의 점착 특성에 관한 연구)

  • Chung, Kyung-Ho;Kang, Min-Kyu;Han, Kyung-A
    • Elastomers and Composites
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    • v.44 no.3
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    • pp.282-289
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    • 2009
  • The pressure-sensitive adhesive(PSA) tapes are widely used as floor-sealing material in Korean constructive industry. However, the general PSA tapes can not seal the apertures completely. This is one of main reasons to cause imperfect finishing. In order to solve the problems, the asphalts were modified by FKM powder and SBS in this study. The physical properties of modified asphalts were examined by measuring the softening point, viscosity, tensile strength and adhesion strength of FKM and SBS modified asphalt. The softening point of SBS modified asphalt was increased greatly due to the formation of network structure in asphalt. Also, the change of adhesion strength of SBS modified asphalt with temperature was not so great comparing to those of pure asphalt and FKM modified asphalt. The best results of pressure-sensitive adhesion could be obtained by the SBS(linear) modified asphalt containing 6 wt.% of linear type SBS.

In vivo Toxicity and Immunoadjuvant Activity of Korean Mistletoe (Viscum album coloratum) Extract Fermented with Lactobacillus (한국산 겨우살이 유산균 발효 추출물의 독성 및 면역증강 효과)

  • Yoon, Taek-Joon;Yang, Woong-Suk;Park, Sung-Min;Jung, Hoe-Yune;Lee, An-Na;Jung, Jin-Hyuk;Kang, Tae-Bong;Yoo, Yung-Choon;Kim, Jong-Bae
    • Korean Journal of Food Science and Technology
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    • v.41 no.5
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    • pp.560-565
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    • 2009
  • In this study, Korean mistletoe extract (KM-110) was fermented with two strains of Lactobacillus (FKM-110) and then toxicity, lectin content, and immune activities were investigated. The lectin content of FKM-110 was about 53-71% lower than that of KM-110. When mice were subcutaneously administered with KM-110 and FKM-110, the $LD_{50}$ obtained for KM-110 treatment was 50-100 mg/kg as compared to 150-200 mg/mL for FKM-110. Each preparation stimulated macrophages directly and enhanced productivity of inflammatory cytokines such as TNF-${\alpha}$ and IL-$1{\beta}$. FKM-110 treatment resulted in lower cytokine production compared to KM-110. When mice were immunized with Keyhol limpet hemocyanin (KLH) antigen along with KM-110 or FKM-110 administration, higher antibody titers to KLH were observed in the KM-110 or FKM-110 groups compared to mice immunized with KLH alone, thereby showing no difference between KM-110 and FKM-110. Therefore, fermentation of Korean mistletoe extract with these Lactobacillus strains decreased toxicity in vivo while the enhancement of immune activity by KM-110 and FKM-110 was similar. These data suggest that KM-110 fermentation tended to decrease lectin content and in vivo toxicity. In addition, other components in the fermented mistletoe extract appear to stimulate immuno-adjuvant activity instead of lectin.

Effect of Magnesium Oxide on Physical and Chemical Properties of FKM Elastomer (FKM Elastomer의 물리적 및 화학적 성질에 미치는 산화마그네슘의 영향)

  • Lee, Chang-Seop;Choi, Gi-Tae;Choi, Han-Hwal
    • Elastomers and Composites
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    • v.38 no.1
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    • pp.57-64
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    • 2003
  • Metal oxide(MgO) was added to FKM rubber in order to develop automotive fuel hose which ran show elastic characteristics under extreme condition. Cure characteristics, physical properties, thermal resistance and fuel resistance of FKM compounded rubber with MgO were investigated. MgO was mixed to FKM rubber materials within the range of $0{\sim}20phr$. From the test results of rheological properties and Mooney viscosity, the $t_{s2}$, $T_{c90}$ values increased as the MgO contents increased in FKM rubber compounding. Hardness and 100% modulus of FKM compounded rubber slightly increased, but tensile strength and elongations at break slightly decreased. From the test results of thermal resistance of rubber specimens at 130, 150, and $170^{\circ}C$ for 70 hrs, the changing rate of physical properties was found to be relatively small. Fuel resistance tests were carried out for fuel A, B, C and D at $40^{\circ}C$ for 70hrs, and the results showed that the changing rate in physical properties was found to increase from Fuel A to D, Furthermore thermal properties of FKM compounded rubber containing MgO were also investigated by using TGA/DSC. The optimum mixing ratio of additive to FKM rubber to get the maximum effect on thermal resistance and fuel resistance, within the range of desirable specification for rubber material, was determined to be 6 phr for MgO.

Compounding and Test of Gasket Rubber for Fuel Cell Stack Application (연료전지 스택 가스켓용 고무재료의 제조와 평가)

  • Hur, Byung-Ki;Kang, Dong-Gug;Kim, Hye-Young;Seo, Kwan-Ho;Park, Lee-Soon
    • Elastomers and Composites
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    • v.42 no.4
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    • pp.232-237
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    • 2007
  • We examined the properties of compound and made compound of the optimum state using the properties of each material to evaluate suitability of FKM, VMQ, EPDM, NBR with gasket for fuel cell which is in general use with the material of gasket. It could be found from the compound made with setting the optimum state that NBR is worse than FKM in the chemical property of matter for a long term, and VMQ is worse than FKM in the elution of a metal ion, and EPDM is worse than FKM in the permeability of gas. As a result of leak evaluation of gasket for fuel cell with using FKM, it appeared leak in short time when contracting pressure is getting lower and sealing pressure is getting higher. And as a result of the life prediction with using Arrhenius model, we could predict that it is possible to continuously drive for 60,000 hours.

Long Term Reliability of Fluroelastomer (FKM) O-ring after Exposure to High Pressure Hydrogen Gas

  • Choi, Myung-Chan;Lee, Jin-Hyok;Yoon, Yu-mi;Jeon, Sang-Koo;Bae, Jong-Woo
    • Elastomers and Composites
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    • v.55 no.4
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    • pp.270-276
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    • 2020
  • The long-term durability of an FKM O-ring used as parts of a hydrogen station was investigated by exposing it to high-pressure gaseous hydrogen for 1, 3, and 7 days at room temperature. Changes in its sealing force were subsequently measured at 150℃ using intermittent compression stress relaxation (CSR). No changes in the tensile properties of FKM O-ring were observed, but its initial and overall sealing forces at 150℃ significantly decreased with increasing exposure time to hydrogen gas. Microvoid formation in the FKM O-ring upon exposure to high-pressure hydrogen was minimized over time after the ring was exposed to atmospheric pressure at room temperature, which prevented changes in its tensile properties. However, applying heat accelerated FKM O-ring oxidation, which decreased its sealing force. These results indicated that identifying changes in the sealing force of rubber materials using intermittent CSR is not sufficient for monitoring changes in mechanical properties under high-pressure hydrogen atmospheres; however, it is suitable for evaluating the long-term durability of sealing materials for hydrogen station applications under similar conditions.

Variable Temperature High-Resolution 19F MAS Solid-State NMR Characterization of Fluorocarbon Rubbers

  • Park, Tae-Joon;Choi, Sung-Sub;Kim, Ji-Sun;Kim, Yong-Ae
    • Bulletin of the Korean Chemical Society
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    • v.32 no.7
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    • pp.2345-2350
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    • 2011
  • Variable temperature high-resolution $^{19}F$ magic angle spinning (MAS) solid-state NMR spectroscopy was used to characterize fluorocarbon (FKM) rubbers. The high-resolution spectra of copolymers made from two monomers, vinylidene fluoride and hexafluoropropene, and terpolymers composed of vinylidene fluoride, hexafluoropropene, and tetrafluoroethylene, were obtained using MAS speeds of up to 18 kHz combined with high temperatures of up to 200 $^{\circ}C$ at a magnetic field strength of 9.4 Tesla. From these high resolution solid-state NMR spectra, we were able to assign the spectral peaks and differentiate the copolymer FKM from the terpolymer FKM. We also determined quantitatively the monomer compositions of each FKM rubber.