Jin Uk Ha

Dr. Jin Uk Ha

Korea Automotive Technology Institute, Cheonan, Republic of Korea
orcid

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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9 August 2016 in Journal of Applied Polymer Science
Verified
Journal Article
Closed access
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SJSun Kyoung Jeoung
Sun Kyoung Jeoung
IHIn Soo Han
In Soo Han
YJYung Jun Jung
Yung Jun Jung
SHSanghyun Hong
Sanghyun Hong
SSSang Eun Shim
Sang Eun Shim
JHJin Uk Ha
Jin Uk Ha

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.

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.

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.

22 April 2023 in Nanomaterials
Verified
Journal Article
Open access
PDF file
PLPyoung-Chan Lee
Pyoung-Chan Lee
DKDongwoo Kang
Dongwoo Kang
JOJi Taek Oh
Ji Taek Oh
JSJae Young Seo
Jae Young Seo
DSDonghyeok Shin
Donghyeok Shin
MKMyeong-Gi Kim
Myeong-Gi Kim
Polypropylene (PP) is used as a housing material in automotive headlamps but can cause fogging as a result of absorbed moisture and temperature differences between the exterior and interior of the housing. In this study, PP was combined with a graphene/montmorillonite hybrid (MMT-G) to yield a nanocomposite with reduced moisture absorption. Crucially, the modified nanofiller had low hydrophilicity and good compatibility with the PP matrix. Notably, the water contact angle of the MMT-G improved by 676%. Furthermore, the maximum moisture absorption of the PP/MMT-G nanocomposites was reduced by up to 11.22% compared to that of commercial PP composites, and the weight of the headlamp housing was decreased by 3.6%. Therefore, the designed nanocomposites are expected to help mitigate headlamp fogging while slightly reducing the housing weight.

11 January 2019 in Journal of Applied Polymer Science
Verified
Journal Article
Closed access
PDF file
JHJin Uk Ha
Jin Uk Ha
YHYe Jin Hwang
Ye Jin Hwang
SJSun Kyoung Jeoung
Sun Kyoung Jeoung
PLPyoung‐Chan Lee
Pyoung‐Chan Lee
SKSoo Young Kim
Soo Young Kim
JYJi Hyun Yeom
Ji Hyun Yeom