• Composites Research
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• v.12 no.6
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• pp.83-89
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• 1999

The impact strength and fracture behavior of rubber/polymer composites were investigated with respect to two factors: (i) characteristic ratio, $C_{\infty}$ as a measure of chain flexibility of the polymer matrix and (ii) the rubber particle size in polymer blend system. In this study C was controlled by the composition ratio of polyphenylene oxide (PPO) and polystyene (PS). Izod impact test and fractographic observation of the fracture surface using scanning electron microscope were conducted. Finite element analysis were carried out to gain understanding of plastic deformation mechanism (shear yielding and crazing) of these materials. Shear yielding was found to be enhanced when the flexibility of matrix polymer was relatively low and the rubber particles were small.

• Proceedings of the Korean Reliability Society Conference
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• 2006.05a
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• pp.27-31
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• 2006

Rubber hoses for automobile radiators are apt to degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under thermal and mechanical loadings. The aging behaviors of the skin part of the hoses due to thermo-oxidative and electro-chemical stresses were experimentally analyzed. Through the thermo-oxidative aging test, it was shown that the surface hardness IRHD(International Rubber Hardness Degrees) of the rubber increased with a considerable reduction of failure strain as the aging time and temperature were large. On account of the penetration of coolant liquid into the skin part the weight of rubber specimens influenced by electro-chemical degradation (ECD) test increased, whereas their failure strain and IRHD hardness decreased. The hardness decreased further as the test site on the hose skin approached to the negative pole.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.58-63
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• 2005

In this research, silicone rubber with additions of inorganic filler, alumina trihydrate$(Al(OH)_3\;:\;ATH)$, was aged acceleratedly and cyclically by the salt-fog and heating. The optimum amount of ATH addition to silicone rubber have been investigated by measurements of leakage current in the change of electrical properties and tensile strength, %elongation in mechanical properties and FT-IR, TG, SEM in the change of the chemical properties. With regard to un-aged silicone rubber, as the ATH addition amount increases, conductive path formation time was shortened in the electrical properties and tensile strength was increased, %elongation was decreased. In case of identical ATH addition amount, as cyclic aging increases, surface resistivity, tensile strength and %elongation were decreased. Considering the cyclic aging, the most effective amount of ATH addition was about 90phr.

• Elastomers and Composites
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• v.30 no.3
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• pp.229-234
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• 1995

Membrane process has been applied widely to petroleum chemistry, fine chemistry, polymer, electronics, food, bioprocessing, and wastewater treatment process. Membrane process has advantage that there's no phase change through separation, energy consumption is smaller than other separation processes. And equipment investment and operation cost are inxpensive too. We prepared the silicone rubber membrane and then separated the heavy metal ion from wastewater. Silicone rubber membrane was prepared using a superitical fluid process and heavy metal ions were separated from the chromium nitrate, ferric sulfate, cupric sulfate, nickel sulfate aqueous solution. The pressure difference between top and bottom of separation apparatus was preserved by vacuum pump, and the removal amount of heavy metal at each separation step were analyzed by instrumental analysis, AAS. The surface and pore of silicone rubber membrane was investigated using SEM, and the capability of wastewater treatment using a silicone rubber membrane was proposed as calculated removal rate of heavy metal after comparing removal amount of heavy metal to amount of heavy metal in mother solution by AAS analysis.

• Computers and Concrete
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• v.12 no.5
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• pp.651-668
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• 2013

Concrete structures need repairing due to various reasons such as deteriorative effects, overloading, poor quality of workmanship and design failures. Cement based repair mortars are the most widely used solutions for concrete repair applications. Various factors may affect the bond strength between concrete substrate and repair mortars. In this paper, the effects of polymer additives, strength of the concrete substrate, surface roughness, surface wetness and aging on the bond between concrete substrate and repair mortar has been investigated. Full factorial experimental design is employed to investigate the main and interaction effects of these factors on the bond strength. Analysis of variance (ANOVA) under design of experiments (DOE) in Minitab 14 Statistical Software is used for the analysis. Results showed that the interaction bond strength is higher when the application surface is wet and strength of the concrete substrate is comparatively high. According to the results obtained from the analysis, the most effective repair mortar additive in terms of bonding efficiency was styrene butadiene rubber (SBR) within the investigated polymers and test conditions. This bonding ability improvement can be attributed to the self-flowing ability, high flexural strength and comparatively low air content of SBR modified repair mortars. On the other hand, styrene acrylate rubber (SAR) modified mortars was found incompatible with the concrete substrate.

• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.1056-1061
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• 1994

Adhesion between cord and rubber compound of brass plated steel cords pretreated at $80^{\circ}C$ in air and at $80^{\circ}C$ and 85% of relative humidity was studied. Surface change of brass with pretreatment was also studied. Brass was oxidized at thermal treatment and oxidation was accelerated with water at humid treatment. Adhesion of pretreated cords decreased with treatment period. The decreasing tendency of rubber coverage was severe. Decrease in adhesion properties due to brass oxidation was discussed relating to the overgrowth of zinc oxide layer.

• Korean Journal of Materials Research
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• v.20 no.2
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• pp.104-110
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• 2010

The characteristics of all polymer composites containing carbon materials are determined by four factors: component properties, composition, structure and interfacial interactions. The most important filler characteristics are particle size, size distribution, specific surface area and particle shape. As a consequence, in this paper we discuss the aspects of the mechanical, electrical and thermal properties of composites with different fillers of carbon black, carbon nanotube (CNT), graphene and graphite and focus on the relationship between factors and properties, as mentioned above. Accordingly, we fabricate rubber composites that contain various carbon materials in carbon black-based and silica based-SBR matrixes with dual phase fillers and use scanning electron microscopy, Raman spectroscopy, a rhometer, an Instron tensile machine, and a thermal conductivity analyzer to evaluate composites' mechanical, fatigue, thermal, and electronic properties. In mechanical properties, hardness and 300%-modulus of graphene-composite are sharply increased in all cases due to the larger specific surface. Also, it has been found that the thermal conductivity of the CNT-composite is higher than that of any of the other composites and that the composite with graphene has the best electrical properties.

• Elastomers and Composites
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• v.54 no.4
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• pp.335-344
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• 2019

In this work, styrene butadiene rubber (SBR) and styrene butadiene styrene (SBS) were used to modify asphalt, resulting in SBR- and SBS-modified asphalt, respectively. The two modified asphalts were emulsified with a nonionic emulsifier (Span 60) and cationic emulsifiers (ID, DDA) and their phase stabilization was investigated via particle size, Zeta potential, and flow behavior analysis. With increasing amount of the mixed emulsifier, the particle size decreased, leading to an increase in viscosity. The shear thinning behaviors and Zeta potential values ranging from 35-65 mV were determined and remained considerably stable. In addition, the adhesion strength and compression strength of the SBR-and SBS-modified asphalt emulsion were evaluated via surface free energy examination. The remarkable adhesion and compression strengths were estimated when 5 phr ID and 6 phr DDA were added to the emulsified asphalt modified with SBR and SBS. Therefore ID and DDA, the two cationic surfactants, played significant roles in improving the dispersion and interfacial adhesion strength, resulting in the improved adhesion and compression strength of the emulsified asphalts modified with SBR and SBS.

• Journal of Environmental Science International
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• v.14 no.6
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• pp.521-524
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• 2005

We introduce a simplified crossing wood drain disperses rain water concentration and is used to protect the road surface from erosion due to flooding over the unpaved road. The efficiency of a simplified crossing wood drain was also investigated. A structure of simplified crossing wood drain can be produced within 10 minutes and installed within 18 minutes. The cost of the this product is 1/5 of that of the existing crossing drain product. The production and installation cost can be reduced according to dexterity. In the context of such applications, the degrees of damage for a rubber pad, which preventing the rain overflow, were varied according to their materials. A type of 8.2mm thick fabric rubber was the most suitable in this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.1
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• pp.42-46
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• 2003

Liquid PVC, which is used widely as fiber coating, has brilliant non-luster effect, but it decreases flexibility of coated fiber surface. We used liquid silicone rubber in elastomer series as a coating material to alleviate this problem. We have conducted the former liquid PVC processing and used pressure of roller and preliminary hardening of processing. In this experiment, We measured 70 degree of hardness, 10.3 MPa of tensile strength and 200fs of tensile elongation of Liquid PVC-coated plastic fiber. We measured 40 degree of hardness, 5.1 MPa of tensile strength and 460% of tensile elongation of Liquid silicone PVC-coated plastic fiber. Therefore, Without the second process, Liquid silicone rubber coating increased non-luster effect and flexibility of plastic fiber surface more than Liquid PVC coating.