• Title/Summary/Keyword: natural rubbers

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A study on the change of the fatigue life and the fracture morphology due to the carbon black on the Natural rubber for vibration-proof (철도차량 부쉬용 방진 천연고무의 카본블랙 강화제에 의한 피로수명과 파단 모폴로지 변화 연구)

  • Kim Jae-Hoon;Hur Hyun-Moo
    • Journal of the Korean Society for Railway
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    • v.8 no.1
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    • pp.21-26
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    • 2005
  • The effects of carbon black on the fatigue lift and the fracture morphology and the carbon black dispersion of the carbon-black filled natural rubbers, for the vibration-proof, were investigated. Different kinds of carbon blacks resulted in different fatigue lift and fracture morphologies, which are classified by micro-scale and macro-scale fracture morphologies. These results be related to the size distribution of carbon black particles, the development of the carbon black agglomerate and the combine forces between the carbon black and the natural rubber.

An Study on the Change of the critical J-value and the Fracture Morphology of the Vibration - Proof Natural Rubber due to Carbon Black (방진부품용 천연고무의 카본블랙에 의한 임계J값과 파단 모폴로지 변화에 관한 연구)

  • 김재훈;정현용;구병춘
    • Proceedings of the KSR Conference
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    • 2002.10a
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    • pp.72-79
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    • 2002
  • The effects of carbon black on the critical J-value and the surface fracture morpology of the carbon-black filled natural rubbers were investigated. Different kinds of carbon blacks resulted in different critical J-values, surface, and roughness. It was noticed that the critical J-value was almost the same regardless of the length of a pre-crack. In addition, different kinds of carbon blacks resulted in different fracture morphologies, and micro-scale and macro-scale roughnesses. The critical J-value could be linearly expressed by the micro-scale roughness and the macro-scale roughness and it seemed related to the size distribution of carbon black particles. And we also found that the macro-scale ms roughness was more sensitive than the micro-scale ms roughness to the critical J-value by the result of correlation coefficient, r$^2$.

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Vibration Characteristics of the Floor Structures inserted with Damping Materials (제진재가 삽입된 바닥 구조의 진동특성)

  • Jeong, Young;Yoo, Seung-Yub;Jeon, Jin-Yong;Park, Jun-Hong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.377-380
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    • 2005
  • Damping materials encompass a broad range of materials, including, but not limits to, pressure sensitive adhesives, epoxies, rubbers, foams, thermoplastics, enamels and mastics. Their common characteristic is that their modulus is represented by a complex quantity, possessing both a stored and dissipative energy component. Loss factor of damping material analyzed more than 2 times than rubber to 1.5 $\sim$ 2.3, could know that Damping layer has excellent attenuation performance in side of vibration reduction. Measurements of vibration using accelerometers by adhesion of Damping layer, square Plate by Separation of Damping layer is less binding of Damping layer, analyzed low loss factor and Natural Frequency by free Vibration of Square Plate.

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An Experimental Study on the Change of the Material Properties and the Fatigue Life of Natural Rubber due to Carbon Black (카본블랙에 의한 천연고무 물성치와 피로수명 변화에 대한 실험적 연구)

  • Kim, Jae-Hun;Kim, Yeong-Hak;Jeong, Hyeon-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.11
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    • pp.1887-1894
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    • 2001
  • The effects of carbon black on the material properties and the fatigue life of the carbon-black filled natural rubbers were investigated. Different kinds of carbon blacks resulted in different fatigue lives, hysteresis, and critical J-values. It was noticed that the hysteresis was inversely proportional to the difference between DBPA and CTAB, and the critical J-value was almost the same regardless of the length of a precrack. In addition, different kinds of carbon blacks resulted in different fracture morphologies, and micro-scale and macro-scale roughnesses. The critical J-value was proportional to the micro-scale roughness. and it seemed relate to the size distribution of carbon black particles. By reviewing all the experimental data. it was finally noticed that the logarithmic value of the fatigue life could be linearly expressed by a multiplication of the critical J-value and the logarithmic value of the hysteresis.

The Effect of Viscosity of Natural Rubber on Incorporation Rate of Carbon Black in The Mixing (배합중 카본블랙 혼입속도에 천연고무 점도가 미치는 영향)

  • Kang, Yong-Gu;Han, Shin;Lee, Kye-Jung;Ryu, Dong-Wan;Park, Chan-Young
    • Journal of the Korean Society of Industry Convergence
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    • v.2 no.1
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    • pp.97-103
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    • 1999
  • The power curve during rubber mixing presents useful information for the understanding of rubber mixing process, because the power curve is determined the mixing state of rubber at the point. The time to the second peak on the power curve is known as carbon black incorporation time, BIT. This study gets the quantity relationship of BIT and viscosity of natural rubber, so by determining the mixing time of the compound on the ground of viscosity of the raw rubber. The mixing with natural rubber and carbon black is examined for various grade natural rubbers, encompassing a wide range of Mooney viscosity. Alter smoothing the mixing power curve using a polynomial, the carbon black incorporation time, BIT, was determined time to second power peak on the curve, The BIT's versus specific values on Mooney viscometer test curve show a linear relation, Especially, the peak of initial maximum torque on Mooney viscometer curve, PMT, is most relevant property relating to the BIT. PMT is useful index for determined optimum mixing time, To apply this results at the mixing, we effectively control the natural rubber mixing but can also know the grading of natural rubber upon processability.

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Degradation of cis-Polyisoprene in Supercritical Tetrahydrofuran (Tetrahydrofuran의 초임계 상에서 cis-Polyisoprene의 분해)

  • Kim, H.J.;Hong, I.K.
    • Elastomers and Composites
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    • v.32 no.5
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    • pp.302-308
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    • 1997
  • Over 1953/54 Karl Ziegler and Giulio Natta independently discovered new types of catalyst. Thus it was able to produce synthetic cis-polyisoprene rubber which has same properties like natural rubber, since then the amount of consumption was increased rapidly. The problem of disposing of used rubbers has become acute in recent years. cis-Polyisoprene was degraded in supercritical tetrahydrofuran and degree of degradation and product were observed by GPC, FT-IR, GC-MS analyses. As a result, degradation of cis-polyisoprene had small dependency upon the operating pressure, and was inhibited in concentration increase. And cis-polyisoprene was degraded into narrow molecular weight distribution oligomer in 3 hours, and more than 10 organic compounds were produced.

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Preblending Effect of Biblends on Properties of the Carbon Black-Filled Rubber Compounds

  • Park, Sung-Seen
    • Macromolecular Research
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    • v.9 no.1
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    • pp.37-44
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    • 2001
  • A premixing effect for the properties of carbon black-filled rubber compounds was investigated using biblends of natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). Degree of mixing of the biblends was controlled by preblending time of 0.0, 2.5, and 5.0 min. Mooney viscosities of the compounds decreased by increasing the preblending time. Of three carbon black-filled compounds of NR/SBR, NR/BR, and SBR/BR compounds, only the SBR/BR blends showed a specific cure characteristics depending on the preblending time. For the bound rubber composition, the NR content was higher than SBR and BR. The difference in the rubber composition ratio of the bound rubber became smaller with increasing the preblending time. Physical properties of the vulcanizates such as hardness, modulus, tensile property, abrasion loss, and tans were also compared. Differences in properties of the compounds were discussed with miscibility of the dissimilar rubbers and degree of mixing.

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A Study on the Thermal Analysis of Fire-Resistance Cable using FEM (유한요소법을 이용한 내화전선의 열해석에 관한 연구)

  • 오홍석;이상호
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.5
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    • pp.338-343
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    • 2004
  • In general, the insulation and protective sheaths on electrical conductors are made of combustible substances like PVC, natural or synthetic rubbers, and other organic or synthetic materials. When an electrical fire starts due to overheating of conductors/joints or sparking/arcing, the first thing to ignite is usually the insulation on the cables. When the insulation bums, the produced fumes are very toxic. To solve the problem, we have surely need the fire resistance cable that doesn't bum in a high temperature and emit toxic fume for operating a disaster prevention installation. In this paper, we have simulated the thermal analysis for the fire resistance cable according to the values of current in a overload and a short, and the values of outside flame with the fire resistance cable of the L's company product(600 V, FR-8 : Four Core) using the finite element method(Flux2D).

Observation of Carbon Nanotube/Elastomer Composites by Atomic Force Microscopy

  • Niikura, Ayako;Nakajima, Ken;Fujinami, So;Ono, Michio;Nishi, Toshio
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.288-288
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    • 2006
  • Natural rubbers (NR) reinforced by multi-wall carbon nanotubes (MWCNT) was found to show extraordinary improvement of mechanical property. We speculated that this was owing to the interfacial phase that surrounded CNT and investigated about the phase by atomic force microscopy (AFM). Using force modulation mode and force-distance curve analyses, we succeeded in obtaining the information of its nanometer-scale rheological property. We found that was actually surrounded by the interfacial phase, that had softer modulus than NR matrix.

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Effect of Changing of Filling Materials in NR-SBR Type Elastomer Based Rubber Materials on Mechanical Properties (필러재료의 변화에 따른 NR-SBR 타입 엘라스토머 기반 고무재료의 기계적물성)

  • Bulbul, Saban;Yasar, Mustafa;Akcakale, Nuretttin
    • Polymer(Korea)
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    • v.38 no.5
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    • pp.664-670
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    • 2014
  • The effects of different filling materials and stabilizers in polymer based materials that are used as shoe soles in the shoemaking industry on the mechanical properties (strength, failure, tensile, tearing, bending etc.) of the final products have been examined in this study. Natural rubber (NR RSS3) and styrene-butadiene rubber (SBR 1502) were used as the main matrix material. New compounds were formed by replacing the fillings in the general compound of the existing factory ($SiO_2$, $CaCO_3$) with 40% (1200 g) blast furnace flue dust, rice husk, reclaimed rubber (recycled) and wood ash. Comparison of the new compounds with the existing compounds revealed a decrease in hardness, density, dimension stability, bending, tearing, % elongation and failure strength and an increase in wearing.