• Elastomers and Composites
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• v.52 no.4
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• pp.237-241
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• 2017

The tensile strength (TS) and elongation-at-break (EB) loss of a CR/CB rubber composite sample prepared for the automotive parts were measured after accelerated thermal ageing at temperatures of 100, 120, 140, and $150^{\circ}C$. The change in TS was observed to be linear from the master curve prepared using the time-temperature superposition-principle (TTSP). An Arrhenius type of shift factor, $a_T$ was used to predict the life time of the sample, and a plot of ln $a_T$ vs. 1/T was also shown to be linear. The activation energy ($E_a$) of the sample was calculated as 70.30 kJ/mole from the Arrhenius plot. The expected life time of the sample was predicted at the given operating conditions by applying Arrhenius analysis. Assuming the $E_a$ value was constant at lower operating condition, life time of the sample was calculated as 2.3 years when the life limit was set as time to reach the 20% decrease of the initial TS value at operating temperature of $40^{\circ}C$.

• Steel and Composite Structures
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• v.22 no.2
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• pp.353-368
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• 2016

This paper extends our recent work on the fatigue behavior of stud shear connectors in steel and recycled tyre rubber-filled concrete (RRFC) composite beams. A series of 16 fatigue push-out tests were conducted using a hydraulic servo testing machine. Three different recycled tyre rubber contents of concrete, 0%, 5% and 10%, were adopted as main variable parameters. Stress amplitudes and the diameters of studs were also taken into consideration in the tests. The results show that the fatigue lives of studs in 5% and 10% RRFC were 1.6 and 2.0 times greater of those in normal concrete, respectively. At the same time, the ultimate residual slips' values of stud increased in RRFC to highlight its better ductility. The average ultimate residual slip value of the studs was found to be equal to a quarter of studs' diameter. It had also been proved that stress amplitude was inversely proportional to the fatigue life of studs. Moreover, the fatigue lives of studs with large diameter were slightly shorter than those of smaller ones and using larger ones had the risk of tearing off the base metal. Finally, the comparison between test results and three national codes was discussed.

• Elastomers and Composites
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• v.58 no.3
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• pp.136-141
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• 2023

Polyacrylic rubber (ACM) is well known for its excellent heat resistance and chemical stability. Additionally, its performance can be readily manipulated by modifying its functional groups, rendering it highly attractive to various industries. However, extreme climate changes have necessitated an expansion of the operating temperature range and lifespan of ACM products. This requires the optimization of both the compounding process and functional-group design. Hence, we investigated the relationship between the cross-linking system and mechanical properties of an ACM with a carboxylic cure site. The crosslink density is determined by chemical kinetics according to the structure of additives, such as diamine crosslinkers and guanidine accelerators. This interaction enables the manipulation of the scotch time and mechanical properties of the compound. This fundamental study on the correlation analysis between cross-linking systems, physical properties, and storage stability can provide a foundation for material research aimed at satisfying the increasingly demanding service conditions of rubber products.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.622-629
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• 2003

Generally, a silicone rubber and a chloride polyethylene(CPE) have been used for the development of high-performance composite EM(ElectroMagnetic) wave absorber. In this study, the EM wave absorption abilities for natural lacquer which is newly suggested in this study as a binder for composite EM wave absorber were investigated to develop an improved EM wave absorber In addition, MnZn ferrite composite EM wave absorber mixed with the natural lacquer were prepared and their absorption ability was also investigated. MnZn ferrite composite EM wave absorber which employs the natural lacquer as a binder showed an improved EM wave absorption characteristics in comparison with the conventional binder such as a silicone rubber and a chloride polyethylene(CPE). The matching frequency and the absorption ability of EM wave absorber mixed with natural lacquer can be controled the change of the thickness of them.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.129-134
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• 2010

This paper investigates effects of rubber inclusion on the strength and physical characteristics of rubber.added composite geomaterial (CGM) in which dredged soils, crumb rubber, and bottom ash are reused for recycling. Several series of test specimens were prepared at 5 different percentages of rubber content (i.e. 0%, 25%, 50%, 75%, and 100% by weight of the dry dredged soil) and three different percentages of bottom ash content (i.e. 0%, 50% and 100% by weight of the dry dredged soil). The mixed soil specimens were subjected to unconfined compression test and elastic wave test to investigate their unconfined compressive strengths and small strain properties. The values of bulk unit weight of the CGM with bottom ash content of 0% and 100% decrease from 14kN/$m^3$ to 11kN/$m^3$ and 15kN/$m^3$ to 12kN/$m^3$, respectively, as rubber content increases, because the rubber had a specific gravity of 1.13. The test results indicated that the rubber content and bottom ash content were found to influence the strength and stress-strain behavior of CGM. Overall, the unconfined compressive strength, and shear modulus were found to decrease with increasing rubber content. Among the samples tested in this study, those with a lower rubber content exhibited sand-like behavior and a higher shear modulus. Samples with a higher rubber content exhibited rubber-like behavior and a lower shear modulus. The CGM with 100% bottom ash could be used as alternative backfill material better than CGM with 0% bottom ash. The results of elastic wave tests indicate that the higher rubber content, the lower shear modulus (G).

• Proceedings of the Korean Magnestics Society Conference
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• 1993.11a
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• pp.66-67
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• 1993

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.886-889
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• 2001

Silicone rubber is being used for the housing material of outdoor high voltage insulators such as composite insulator, bushing, surge arrestor and cable terminator because of good tracking and erosion resistance, good hydrophobicity and recovery of hydrophobicity and chemical stability. But, the leakge current occurs on surface of the composite polymeric insulation materials when the insulator is used for a long time with severe contaminative condition and it can lead the contamination flashover. So the leakage current is important to estimate the condition of the silicone rubber surface. In this paper, aging characteristics of silicone rubber used for outdoor insulation have been hydrophobicity of silicone rubber in salt fog chamber with average leakage current monitoring for observing the transformation of surface degradation properties of silicone rubber with different ATH(alumina trihydrate, A1$_2$O$_3$$.$3H$_2$O) filler contents. The experimental results show that a higher peak leakage current and to raise a long time for tracking with increasing amount of ATH by the salt fog and heat recycle ageing.

• Elastomers and Composites
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• v.54 no.1
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• pp.22-29
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• 2019

Chitosan-polyvinyl alcohol (PVA) -bamboo charcoal/silica (CS-PVA-BC/SI) hybrid fillers with compatibilized styrene-butadiene rubber (SBR) composites were fabricated by the interpenetrating polymer network (IPN) method. The structure and composition of the composite samples were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). The viscoelastic behaviors of the rubber composites and their vulcanizates were explored using a rubber processing analyzer (RPA) in the rheometer, strain sweep and temperature sweep modes. The storage and loss moduli of SBR increased significantly with the incorporation of different hybrid fillers, which was attributed to the formation of an interphase between the hybrid fillers and rubber matrix, and the effective dispersion of the hybrid fillers. The mechanical properties (hardness, tensile strength, oxygen transmission rate, and swelling rate) of the composite samples were characterized in detail. From the results of the mechanical test, it was found that BC-CS-PVA0SBR had the best mechanical properties. Therefore, the BC-CS-PVA hybrid filler provided the best reinforcement effects for the SBR latex in this research.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1355-1357
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• 1997

In this study, the ferrite/rubber composite microwave absorbers mixed Ni-Zn ferrite and $Ni_2Y$ ferroxplana were prepared in order to control matching condion. The variation of the material constants($\dot{\varepsilon}$, $\dot{\mu}$) and microwave absorbing characteristics were investigated with various ferrite mixing ratio. The material constants of ferrite/rubber composite microwave absorber could be controlled by variation ferrite mixing radio. The matching frequency and thickness could be controlled with various ferrite mixing ratio.

• Polymer(Korea)
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• v.37 no.3
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• pp.255-261
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• 2013

This paper introduced a new preparation method of a composite rubber by mixing BR (butadiene rubber) and CIIR (chloro-isobutyl rubber) for the purpose of improving frictional property of BR. Since BR has high abrasion and low frictional properties, its frictional property needs to be enhanced in order to be used as an outsole of a sport shoe. Such enhancement was difficult to achieve by simple blending of CIIR. In here, CIIR was added into BR matrix after CIIR was pre-crosslinked for a time period, and both high frictional and high abrasion resistance properties were achieved. Our experiments showed that the composite rubber blend of 60% of BR and 40% of pre-crosslinked CIIR had desired BR's frictional and abrasion resistance properties for sport shoes.