• Elastomers and Composites
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• v.33 no.4
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• pp.231-237
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• 1998

In order to investigate the physical properties of rubber blend compound, this experiment was carried out on the cure rate, loss tangent, reinforcement and abrasion properties of S-SBR (solution styrene-butadiene rubber) blends containing silane coupled silica and E-SBR (emulsion styrene-butadiene rubber) blends containing carbon black as a model compound. E-SBR blend showed the highest total bound rubber(TBR), while S-SBR blends showed constant TBR level regardless of rubber type. Rapid cure rate was achieved when the styrene and vinyl content of rubber microstructure decreased and TBR content of rubber compounds increased. The modulus as the index of rubber reinforcement showed the linear relation with TBR content. The large amount of PICO loss was observed when the styrene and vinyl content of rubber microstructure increased, while the small amount of PICO loss was observed when the ratio of bu-tadiene increased in the S-SBR blends with silane copuled silica. The high loss tangent at $0^{\circ}C$, the low loss tangent at $60^{\circ}C$, and the large difference of loss tangent were shown in the S-SBR blends with high styrene content compared to E-SBR blend.

• Elastomers and Composites
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• v.33 no.4
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• pp.281-289
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• 1998

Tensile properties including Young's modulus and tear strength were measured for four different rubber compounds; natural rubber(NR), styrene-butadiene copolymer(SBR), ethylene-propylene diene monomer (EPDM), and brominated isobutylene-p-methyl-styrene copolymer(BIMS) as a function of temperature and degree of cure. To see the effect of over cure, a measurement was made of the tensile strength and swelling behavior of the over-cured rubber compounds. Young's modulus, E, was found to have linear dependency on the degree of cure for all rubber compounds. EPDM and BIMS showed the highest and lowest slopes, respectively. The slope of NR and SBR lay between EPDM and BIMS. Tear strength, Gc, decreased in the order of NR>BIMS>SBR>EPDM. As the cure time was extended the degree of cure of NR and SBR decreased, while that of BIMS increased. EPDM showed little change in the degree of cure.

• Elastomers and Composites
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• v.35 no.3
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• pp.173-179
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• 2000

Cure characteristics. tensile properties, and dynamic properties were investigated on the carbon black-filled natural rubber compounds, in which three typical vulcanization types conventional vulcanization(Conv), semi-efficient(Semi-EV), and efficient(EV) vulcanizations were used. The effects of vulcanization temperature on both the mechanical property and aging resistance of rubber compounds were also investigated. The Conv cure system showed a slightly slower rate of vulcanization than those of Semi-EV and EV ones. On the other hand, it showed a higher value in the maximum torque of cure curve. Higher tensile moduli were observed in Conv system than those in Semi-EV and EV ones, while lower elongation at break were obtained in Conv one. The tensile strength at break were found to be about the same for three cute systems. Hardness, modulus, and tensile strength decreased with increasing the vulcanization temperature, and the degree of changes in the properties was found to be smaller for EV and Semi-EV systems than that in Conv one. The EV system was found to be superior in thermal-aging resistance to Conv one.

• Elastomers and Composites
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• v.33 no.4
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• pp.274-280
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• 1998

Order of reaction, rate constant, activation energy for vulcanization reaction, crosslinking density, and elastic constant of the network produced by sulfur curing were investigated on the SBR/BR blends containing silica and carbon black under same cure system. The reaction order was shown to be first order regardless of filler types. The carbon black filled rubber compounds showed higher rate constant compared to silica filled compounds. But activation energy appeared to be same regardless of filler type and rubber blend ratio. The crosslinking density and elastic constant is higher in the carbon black filled compound compared to silica filled compounds because of strong interaction between rubber and carbon black. On the other hand, crosslinking density and elastic constant were decreased with increasing the butadine rubber content in rubber blends. From the comparison of combined sulfur content in the vulcanized rubber, sulfur content in the silica filled compound become constant 20min later after reaction initiates but sulfur content in the carbon black filled compound become constant 10min later after reaction starts. The silica compound has a longer induction time ($t_2$) and optimum cure time($t_{90}$) compared to those of the carbon black filled compound.

• Elastomers and Composites
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• v.33 no.4
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• pp.238-245
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• 1998

In this paper, the electric property was investigated for insulation diagnosis of radiation of EPR electric power cables by partially irradiation with $^{60}Co-{\gamma}$ rays. As the rate of radiation increased from 100Mrad to 200Mrad, charging current and discharging current were increased from $1.03{\times}10^{-7}$(A) to $4.3{\times}10^{-9}$(A). In addition, we found charging current and discharging current of cables subjected to 50% and 16.7% irradiation changed the length of the part 1/2 to 1/6 as in comparison with cables degraded by 100% irradiation. For 22m and 66m of cables which had not been degraded yet, we realized the value of charging current and discharging current of 66m cables is three times higher than 22m cables. From these results, it is demonstrated that the possibility of utilizing charging current and discharging current as the diagnosis method of insulation degradation with irradiating EPR cables by $^{60}Co-{\gamma}$ rays.

• Elastomers and Composites
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• v.33 no.4
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• pp.267-273
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• 1998

Isocyante terminated urethane prepolymers were synthesized by the reaction of 4,4'-dimethyl phenyldiisocyanate(MDI) and ester type polyols such as ethylene glycol/ butanediol adipate(EBA), neopentylglycol/butanediol adipate (NBA) and hexanediol adipate (HA) . All of the NCO-terminated urethane prepolymers are solid at room temperature, but they become mobile enough to be disposed onto a substrate upon heating about $80^{\circ}C$. Subsequently, they are solidified and cured through the reaction with moisture. Tensile behavior of the ore-thane hotmelt exhibits characteristic features depending on the type of polyol. The adhesive strength determined by single lap shear joint is higher in order of HA, NBA and EBA based ore thane hotmelt, which can be correlated with the magnitude of breaking energy of the cured films. The failure mode are cohesive for all cases and the adhesive strength increases as the test is performed faster. This indicates that the strength of the adhesive joint is primarily dependent upon the bulk properties of the adhesives.

• Elastomers and Composites
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• v.39 no.4
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• pp.286-293
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• 2004

Ester- and ether-based thermoplastic polyurethanes of different hardness were injection molded at different mold temperatures and effects of mold temperature on the physical properties of TPUs were investigated. Glass transition temperatures of soft segments of TPUs were hardly changed by mold temperatures. The phase separation of soft and hard segments of injection molded TPUs were affected little by mold temperatures. However, crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength of injection molded TPUs decreased with increasing mold temperatures for TPUs of high hardness. However, injection molded TPUs of low hardness showed increases of crystallinity of hard segments, temperature range of rubbery plateau, and tensile strength with increasing mold temperatures. Different physical properties of injection molded TPUs depending on mold temperatures were attributed to different crystallization and physical crosslinking effects of hard segments.

• Elastomers and Composites
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• v.38 no.3
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• pp.195-205
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• 2003

This paper presents an analytic method and a design technique for golf shoes with air-cycled pump in the midsole. The golf shoes are modeled using the finite element method for better design by considering the configuration of the midsole and the outsole, which compose the golf shoes. Also the optimum size and shape of air-cycled pump in the midsole is examined. The values or standard human pressure for boundary conditions are adopted for the FEA(Finite Element Analysis). The unknown constants of the strain energy function of Ogden type are observed in accordance with the axial tension test. By the commercial FEM software for nonlinear analysis, MARC V7.3, the strains and the values of volume change for the midsole and the outsole are obtained, respectively. It can be concluded that results obtained by FEM in the midsole and the outsole are different depending on the characteristic of elastomer The results reported herein provide better understanding of analyzing the golf shoes. Moreover, it is believed that those properties of the results can be utilized in the shoes industry to develop the effective design method.

• Elastomers and Composites
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• v.39 no.4
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• pp.301-308
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• 2004

Three types of parylene (PA-N, PA-C, PA-D) were used for coating the surface on natural latex rubbers in order to improve surface characteristics including mechanical properties and biocompatibility. The parylene coating was the CVD (chemical vapor deposition) method, and the surface properties of the modified latex were measured. Annealing effects on the mechanical properties of the coated latex were also investigated. The adhesion between latex and parylene was good for all the types of parylene used. As annealing temperature was increased, latex modified with PA-N became more hydrophobic, while the latex treated with PA-C and PA-D became more hydrophilic. As the annealing temperature was raised, the tensile strength was increased, and the elongation was decreased. The biocompatibility was noticeably improved on the latex surface modified with the parylenes through CVD method.

• Elastomers and Composites
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• v.38 no.3
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• pp.206-212
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• 2003

This paper presents an analytic method and a design technique for golf shoes with coolant in the insole. The golf shoes are modeled using the finite element method for precision by considering the configuration by the insole, the midsole and the outsole, which compose the golf shoes. The values of standard human foot temperature for heat transfer boundary conditions are adopted for the FEA(Finite Element Analysis). By the commercial FEM software for heat transfer analysis, MARC V7.3, the temperature and the amounts of heat flux change for the insole are obtained, respectively. It can be concluded that results obtained by FEM in the insole are different depending on the characteristic of heat transfer. The results reported herein provide better understanding of analyzing the golf shoes. Moreover, it is believed that those properties of the results can be utilized in the shoes industry to develop the effective design method.