Papers by Author: Jong Kwang Park

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Authors: Bok Choon Kang, Chathura Nalendra Herath, Jong Kwang Park, Yong Hwang Roh
Abstract: Carbon, aramid and glass fibers are inherently superior to conventional textile fibers in terms of mechanical properties and other characteristics. However, each material has its inherent advantages and disadvantages and it is usually recommended to hybridize them to fully benefit of their high performance in practical applications to many products. This paper is concerned with an air texturing process for hybridization of different reinforcement filament yarns. A normal air texturing machine was selected for process development and modified to suit testing purposes. The modified process for hybridization was introduced mainly in terms of air-jet nozzles employed in experiments. With the proposed air texturing process machine, three types of air-nozzle were applied to the experimental work. Three different filament materials were employed in experiments and they are carbon (CF), aramid (AF), and glass (GF). As matrix materials, polyether-ether (PEEK), polyester (PES), and polypropylene (PP) were selected and experimented. Hybrid yarns produced form the proposed process was evaluated optically in terms of bulkiness, arranging, breaking, and mixing, respectively. The experimental results were also summarized in terms of relationships between applied air pressure and yarn count, and variation in count. As a whole, it was concluded from the experiments that the proposed texturing process could be successfully applied to the practical hybridization of different reinforcement filament yarns. It was also revealed from the experiments that the air pressure in the proposed process is not a significant parameter on the pressing in terms of yarn count.
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Authors: Chathura Nalendra Herath, Bok Choon Kang, Jong Kwang Park, Yong Hwang Roh, Beong Bok Hwang
Abstract: This paper is concerned the breaking elongation properties of Carbon/Aramid-, Carbon/Glass- and Aramid/Glass- matrix hybridized commingling yarns. The hybrid yarns produced by commingling process were investigated in terms of breaking elongation property. In experiments, carbon (CF), aramid (AF), and glass (GF) filament yarns were combined. In this study, selected matrix materials include Polyether-ether-Keeton (PEEK), and polyester (PES), or polypropylene (PP). The volume content of filament in hybrid yarn cross section was maintained at 50% for both reinforced and matrix, ant hybrid yarns count at 600 tex, respectively. The reinforcement to matrix filament combination was selected as 1:1 proportion. The effect of different air pressures and material combinations was investigated in terms of breaking elongation. In experiments, each type of hybrid yarn sample has been tested 20 times at the testing speed of 10mm/min. under 3 bar of yarn clamping pressure. Since breaking elongation is one of most important properties in textile fiber, it was examined closely with reference to the first breaking point of commingling-hybrid yarns. It was concluded from experiments that hybrid yarns with higher breaking elongation and higher tensile strength tend to show better force-elongation relationship. It was also known from experiments that the combination of two reinforcement filament yarns gives always much better results than a single reinforcement filament yarns in terms of elongation property. GF/AF/matrix is shown very much better elongation properties. PP and PES gives higher elongation than PEEK as a matrix material.
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