Sun Kyoung Jeoung

Dr. Sun Kyoung Jeoung


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 April 2023 in Polymers
Verified
Journal Article
Open access
PDF file
HIHyungu Im
Hyungu Im
SJSun Kyoung Jeoung
Sun Kyoung Jeoung
Ethylene–propylene–diene monomer (EPDM) rubber is one of the rapidly developing synthetic rubbers for use as a gasket material in proton exchange membrane (PEM) fuel cell applications. Despite its excellent elastic and sealing properties, EPDM faces challenges such as molding processability and recycling ability. To overcome these challenges, thermoplastic vulcanizate (TPV), which comprises vulcanized EPDM in polypropylene matrix, was investigated as a gasket material for PEM fuel cell applications. TPV showed better long-term stability in terms of tension and compression set behaviors under accelerated aging conditions than EPDM. Additionally, TPV exhibited significantly higher crosslinking density and surface hardness than EPDM, regardless of the test temperature and aging time. TPV and EPDM showed similar leakage rates for the entire range of test inlet pressure values, regardless of the applied temperature. Therefore, we can conclude that TPV exhibits a similar sealing capability with more stable mechanical properties compared with commercialized EPDM gaskets in terms of He leakage performance.

12 March 2022 in Polymers
Verified
Journal Article
Open access
PDF file
PLPyoung-Chan Lee
Pyoung-Chan Lee
SKSu Young Kim
Su Young Kim
YKYoun Ki Ko
Youn Ki Ko
JHJin Uk Ha
Jin Uk Ha
SJSun Kyoung Jeoung
Sun Kyoung Jeoung
MKMyeong-Gi Kim
Myeong-Gi Kim
Polyamide 46 (PA46) is used in various automotive parts because of its excellent heat resistance and mechanical properties. This study aims to improve the frictional properties of PA46 using the lubricating ability of graphene. Nanocomposites are prepared via two mixing methods: Graphene powder is compounded directly with PA46 pellets through a twin-screw extruder, or PA46 powder is added to graphene dispersion for self-adsorption, and subsequently, it is dried and compounded with PA46 through the twin-screw extruder. Application of the nanocomposite in the friction field is evaluated via the pin-on-disk method. The coefficient of friction of the nanocomposite prepared by self-adsorption is lower than that of the nanocomposite prepared by direct compounding. The mechanical properties of the nanocomposite fabricated by self-adsorption are superior to those of other materials. This can be attributed to the uniform dispersion of graphene and the strong attractive force between the PA46 matrix and graphene.

17 May 2022 in Polymers
Verified
Journal Article
Open access
PDF file
PLPyoung-Chan Lee
Pyoung-Chan Lee
SKSu Young Kim
Su Young Kim
YKYoun Ki Ko
Youn Ki Ko
JHJin Uk Ha
Jin Uk Ha
SJSun Kyoung Jeoung
Sun Kyoung Jeoung
MKMinsu Kim
Minsu Kim
This study investigated the service life prediction of fluorocarbon elastomers that are used in automotive vapor fuel hoses under thermal environments. The changes in mechanical properties such as the tensile strength, elongation, compression set (CS), and hardness according to thermal aging were investigated for two types of ternary fluoroelastomers. Destructive tests of the tensile strength and elongation showed large variations in the mechanical properties under the same condition because there is no continuity of samples. In contrast, nondestructive tests of the CS and hardness showed little variations in the mechanical properties under the same condition. The elongation, CS, and hardness were selected as the physical parameters for service life prediction as they showed a tendency according to the aging temperature, which is an accelerating factor. The effective activation energy derived using each physical parameter was 74.91–159.6 kJ mol−1, and the service life was 17.8–140 × 103 h based on B10. In this study, hardness, which has a small deviation between samples, is considered appropriate as mechanical parameter for predicting the service lifetime.

23 June 2023 in Polymers
Verified
Journal Article
Open access
PDF file
JHJin Uk Ha
Jin Uk Ha
SBSeok H. Bae
Seok H. Bae
YCYu Jin Choi
Yu Jin Choi
PLPyoung-Chan Lee
Pyoung-Chan Lee
SJSun Kyoung Jeoung
Sun Kyoung Jeoung
IHIN SOO - HAN
IN SOO - HAN
This study aims to analyze tire wear particulate matter (TWP) from tread rubber with different formulations and to compare the concentration of TWP with different wear devices. The TWP generated during the abrasion of truck and bus radial (TBR) tires were examined, and the effect of using different types of rubber and carbon black (CB) were investigated. When natural rubber (NR) was solely used as the tire tread rubber material, there was a higher concentration of 5–10 µm TWP. However, when the tread formulation consisted of NR mixed with butadiene rubber, the TWP concentration decreased. Changing the type of CB also reduced the amount of TWP in the 2.5 µm size range. The TWP concentration in the specimens increased with increasing speed and vertical load. The TWP generated during the abrasion tests using wear testers and tire simulators exhibited similar trends. These findings suggest that modifying tire tread formulations can effectively control the distribution and amount of TWP generation.

1 January 2016 in AIP Conference Proceedings
Verified
Conference Paper
Closed access
SJSun Kyoung Jeoung
Sun Kyoung Jeoung
YHYe Jin Hwang
Ye Jin Hwang
HLHyun Wook Lee
Hyun Wook Lee
SSSoon Keun Son
Soon Keun Son
HKHyung Sik Kim
Hyung Sik Kim
JHJin Uk Ha
Jin Uk Ha
Carbon fiber reinforced plastics (CFRP) have a lot of attention from industry and academia due to its excellent mechanical property. It has been used for aircraft, automotive and so on, since it can replace metallic materials and reduce total weight with increased physical properties. However, the manufacturing process and the material cost are still challenging to be commercialized in the automotive market. Therefore, many researchers are trying to minimize materials and process cost for broadening their applications. In this study, thermoset epoxy resins were used for binder of CFRP. Epoxy resins were investigated in order to figure out optimized curing speed under vacuum assisted resin transfer molding (VARTM) processing condition. Mechanical properties of CFRP with different carbon fiber orientation and woven carbon fiber were compared to mathematically simulated results. In order to develop the application of automobile component, reliability tests of CFRP were carried out. Tensile strength of CFRP is increased when the orientation angle between fiber and axis of load was decreased (90°→ 0°). It is considered that epoxy and carbon fiber absorbed the tensile energy because the orientation of fiber and the load bearing are matched with axis direction. In addition, the CFRP automobile engine hood was fabricated by VARTM process. Drop weight impact tests (20kg & 100kg weight) were carried out in order to simulate crash performance of CFRP engine hoods.

29 August 2025 in Polymers
Verified
Journal Article
Open access
PDF file
SHSosan Hwang
Sosan Hwang
HJHyeon Woo Jeong
Hyeon Woo Jeong
AKAsell Kim
Asell Kim
TKTae-Soon Kwon
Tae-Soon Kwon
SJSun Kyoung Jeoung
Sun Kyoung Jeoung
YQYingjie Qian
Yingjie Qian
This study presents the design and fabrication of silicone–urethane hybrid foam (SUF) to improve fire safety in transportation seating. Tin(II) 2-ethylhexanoate (Sn(OCT)2) was used to catalyze reactions between bifunctional isocyanates, polyols, and vinyl-terminated PDMS, enabling simultaneous curing and foaming. Sn(OCT)2 effectively facilitated both the foaming and gelation processes of silicone and urethane chemistries. The resulting SUF demonstrated a 44.55% reduction in peak heat release rate (PHRR) compared to UF, due to the PDMS network’s synergistic flame-retardant and barrier effects. Additionally, the crosslinked PDMS structure maintained strong mechanical integrity. This study offers a simple and effective approach for producing SUF with enhanced fire safety.