• Title/Summary/Keyword: vulcanizates

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Preparation of Sulfur Crosslinkable EVA and Blend With Rubbers (황가황형 EVA의 제조 및 고무와의 블렌드)

  • Jin, Je-Yong;Choi, Sei-Young
    • Elastomers and Composites
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    • v.34 no.3
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    • pp.229-238
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    • 1999
  • In this study, double bond, unsaturated group was introduced to the main chain of EVA by chemically treating EVA, nondiene polymer. Benzene sulfonic acid, ENB and DCPD were used as a third element. Also, from blending CR and SBR, conventional synthetic rubber we prepared vulcanizates and examined their physical properties. The datum lead to the following conclusion that some problems were modified; limited temperature in use and mechanical properties like hardness, tensile strength, tensile stress, and elongation rate of thermoplastic EVA, keeping the following advantages of original EVA; green strength, injection molding by Pressure, adhesion, tackiness, dimensional stability, and ozone resistance, etc. It is expected that continuous research of the modification between nondiene and diene polymer will improve what were shown disadvantages in synthetic polymer; processing, oxidation resistance, and adhesion. In addition, it will be possible to continue process of rubber products by utilizing possible fluidity for fusion of EVA.

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Characteristics of Thermoplastic Vulcanizate Weatherstrip Prepared by Water-Foaming Technique (수발포 기술을 적용한 열가소성 고무 Weatherstrip 특성)

  • 이성훈;김진국
    • Polymer(Korea)
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    • v.27 no.5
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    • pp.436-442
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    • 2003
  • Thermosetting elastomer such as EPDM (Ethylene Propylene Dien Rubber) has been applied to the sponge weatherstrip of a vehicle as a main material. However, the thermosetting elastomers have limited recycling and have brought about the environmental problems. Furthermore, many steps of the manufacturing process such as formulation, mastication and vulcanization make difficult to control uniformity of the endproducts. These problems of current EPDM weatherstrip necessitated development of a new recyclable material, Thermoplastic Vulcanizates (TPV). In this study the influence of the water contents, and the processing conditions. On the foam density and structure in water blowing process was carried out. We found that TPV also can be foamed with water, maintaining the uniformity form this study. Therefore, many inevitable problems of EPDM weatherstrip can be solved, and this new technique is expected to take a roll of making a breakthrough in the rubber industry.

Effect of trans-octylene rubber(TOR) on the properties of NBR/EPDM rubber blends (Trans-octylene rubber(TOR)의 첨가가 NBR/EPDM 고무블렌드의 물성에 미치는 영향)

  • Shin, Yung-Sik;Chang, Young-Wook
    • Elastomers and Composites
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    • v.35 no.2
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    • pp.149-156
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    • 2000
  • trans-octylene rubber(TOR) was melt-blended with an incompatible NBR/EPDM (70/30) blend. Mixing torque and temperature were reduced as TOR was added to the NBR/EPDM blend. Rheometer results indicated that TOR participated in vulcanization and became a part of network. A scanning electron micrograph demonstrated that EPDM was dispersed in NBR matrix in the blend and the addition of TOR led to a finer dispersion of EPDM particles. On the addition of TOR, the tensile strength, the tensile strain as well as the modulus of the blend vulcanizates increased. The ozone resistance of the blends determined in terms of critical stress-strain parameter was significantly enhanced in the blend as TOR was added. Improvements in the properties were believed to be associated with fine morphology and the increase in crosslink density due to the chain entanglement of the ternary blends.

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Filler-Elastomer Interactions. 1. Roles of Modified Carbon Black Surfaces to Enhance Mechanical Properties of Carbon Black/Rubber Vulcanizates (충전재-탄성체 상호작용. 1. 표면처리된 카본블랙이 카본블랙/고무 복합재료의 기계적 물성에 미치는 영향)

  • Kim, Jeong-Soon;Nah, Chang-Woon;Park, Soo-Jin
    • Elastomers and Composites
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    • v.35 no.2
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    • pp.98-105
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    • 2000
  • Using FT-IR and contact angle measurements it is observed that the chemical surface treatments on virgin carbon blacks lead to a change of the surface properties, including surface functionality and surface free energy It is found that the developments of surface functional groups on acidically and basically treated (ACB and BCB in this study, respectively) carbon blacks are largely correlated with the specific component of surface free energy of the carbon blacks. However, a significant advantage of compounding composites is gained by BCB or NCB (nonpolar chemical treatment) specimens, resulting in improving the hardness, elongation at break, and tensile strength. Particularly, it is seen that the tensile strength of the composites are greatly depended on the London dispersive component of surface free energy determined from the contact angle measurements. It is then concluded that the London dispersion component of carbon blacks plays an important role in an organic rubbers-based compounding composite system.

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Influence of Mixing Procedure on Properties of Rubber Compounds Filled with Both Silica and Carbon Black (배합 공정이 실리카와 카본블랙으로 보강된 고무 배합물의 특성에 미치는 영향)

  • Joo, Chang-Whan;Kim, Dong-Chul;Choi, Sung-Seen
    • Elastomers and Composites
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    • v.37 no.1
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    • pp.14-20
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    • 2002
  • Silica-filled rubber compound needs longer mixing time compared to carbon black-filled one since it has poor dispersion or the filler. Influence of the mixing procedure on the properties of natural rubber compound filled with both silica and carbon black was studied. The discharge temperature of the master batch (MB) mixing was $150^{\circ}C$. The mixing time was longer when silica and carbon black were loaded separately than when loaded simultaneously. The mixing time was longer when silica was loaded first than when carbon black is loaded first. The compounds prepared by one MB step (conventional mixing) were compared with the compounds prepared by two MB steps (two-step mixing). Scorch times of the two-step mixing compounds were longer than those by the conventional mixing ones. Bound rubber contents of the formers were lower than those of the tatters. The two-step mixing vulcanizates had longer elongation at break, higher tensile strength, and better fatigue life.

Effects of temperature on Hardness and Stiffness of NR and SBR Vulcanizates (NR과 SBR 가황물의 경도와 강성도 대한 온도의 영향)

  • Jin, Hyun-Ho;Hong, Chong-Kook;Cho, Dong-Lyun;Kaang, Shin-Young
    • Elastomers and Composites
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    • v.42 no.3
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    • pp.143-150
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    • 2007
  • Hardness of rubbery materials, which is important for dimensional stability and product performance, was investigated upon temperature change in this study. A newly developed IRHD (International Rubber Hardness Degree) tester was used to measure the hardness changes of NR and SBR specimens at various temperatures and the hardness values were compared with the Young's modulus. The harness and Young's modulus of NR and SBR showed an abrupt change near the glass transition temperatures. The hardness and Young's modulus were increased by increasing temperature due to the increased random chain conformation of molecules. The effect of temperature on hardness and Young's modulus of NR and SBR specimens filled with carbon black and silica was decreased by increasing filler content.

Preparation and Properties of EPDM/Zinc Methacrylate Hybrid Composites (에틸렌 프로필렌 디엔 고무/메타크릴산아연 하이브리드 복합체의 제조와 물성에 관한 연구)

  • Chang, Young-Wook;Won, Jong-Hoon;Joo, Hyun-Seok
    • Elastomers and Composites
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    • v.40 no.1
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    • pp.59-65
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    • 2005
  • Zinc methacrylate(ZMA) was incorporated into ethylene-propylene diene rubber(EPDM) by direct mixing of the metal salt with the rubber or was in-situ prepared in the rubber matrix through neutralization reaction of zinc oxide(ZnO) and methacrylic acid(MAA). Tensile and tear tests showed that ZMA had a great reinforcing effect for the EPDM. It was also found that ZMA reinforced EPDM vulcanizates can retain their mechanical properties under thermo-oxidative aging. Moreover the incorporation of ZMA induces a substantial improvement in the adhesive strength of the EPDM onto aluminum substrate. The reinforcing effect and an enhancement in adhesion was greatly manifested when the ZMA is in-situ formed with an excess amount of ZnO. The extraordinary improvement in the properties is supposed to be related with the formation of ionic crosslink as well as the degree of dispersion or ZMA domain in the rubber matrix.

The Influence of Plasma Surface Modification on Frictional Property of Natural Rubber Vulcanizates

  • Nah, C.;Kim, D.H.;Mathew, G.;Jeon, D.J.;Jurkowski, B.;Jurkowska, B.
    • Elastomers and Composites
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    • v.39 no.1
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    • pp.12-22
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    • 2004
  • The plasma surface modification of natural rubber vulcanizate was carried out using chlorodifluoromethane in a radio-frequency (13.56 MHz) electrodeless bell type plasma reactor. The modification was qualitatively assessed by Fourier transform infrared spectroscopy. The frictional force of the plasma-treated surface was found to decrease with the time of plasma treatment. An increase in the surface polarity, as evidenced by the decrease in contact angle of a sessile drop of water and ethylene glycol on the natural rubber vulcanizate surface, was noted with the plasma modification. In the case of similar plasma treatment of glass surface, only a reduction in the polarity was observed. The use of geometric and harmonic mean methods was found to be useful to evaluate the London dispersive and specific components of surface free energy. Irrespective of the method used for evaluation, an increasing trend in the surface free energy was noted with increasing plasma treatment time. However, the harmonic mean method yielded comparatively higher values of surface free energy than the geometric mean method. The plasma surface modification was found to vary the frictional coefficient by influencing the interfacial, hysteresis and viscous components of friction in opposing dual manners.