• 한국운동역학회지
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• 제21권2호
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• pp.231-241
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• 2011

The purpose of this study was to analyze the distribution of foot pressure generated by active materials of a functional insole. Comfort is an important consideration while selectingfootwear and insoles. Consequently, it has an influence on injury. The development of new materials for functional insoles is considered one of the more important points for their manufacture. The method adopted in this study is as follows. First, ten healthy males were selected as subjects for the study. Each subject's foof was pre-screened podoscope(Alfoots, Korea) to check for the presence of any foot abnormalities, Two kinds of equipment were used for the study: a foot pressure device from Pedar-X, Germany, and a treadmill from Pulsefitness, UK. Next, each subject was asked to test four types of insoles(insoles of outdoor shoes, indoor shoes, walking shoes, and sports shoes) via walking trials on the treadmill at a constant speed of 4.2 km/h. The pressure distribution data(contact area, maximum force, maximum peak pressure, and maximum mean pressure) was collected using the pressure device at a sampling rate of 100 Hz. Results of the tests showed that all four types of functional insoles increased contact areas whit the foot. Further, functional insoles of walking shoes and sport shoes decreased the foot pressure. From these results, we conclude that the active materials of functional insoles of shoes can increase the contact area and provide greater comfort.

• Elastomers and Composites
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• 제55권4호
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• pp.314-320
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• 2020

This study focused on experiments with polyethylene glycol (PEG) and glycidyl methacrylate (GMA), which are functional additives for water-expandable rubber. Polychloroprene rubber (CR)/superabsorbent polymer (SAP) composites were prepared and their cure behaviors, mechanical properties, water absorption rates, and surface morphology were measured based on the functional additives applied. When PEG and GMA were applied to the composites, the water absorption rate increased-including the initial rate-compared to that measured when functional additives were not used. The results also show that PEG has a hydrophilic functional group, which allows it to absorb more water, and GMA acts as a coupling agent between CR and SAP. However, with the introduction of functional additives, the cure rate slowed down and the mechanical properties also decreased.

• Elastomers and Composites
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• 제57권4호
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• pp.129-137
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• 2022

Low molecular weight liquid butadiene rubber (LqBR) is a processing aid that can resolve the migration problem of tire tread compounds. Various studies are being conducted to replace the petroleum-based processing oil with LqBR. However, the effect of the loading time of LqBR in the compounding process on silica dispersion and vulcanizate properties is not well known. In this study, we analyzed silica dispersion, vulcanizate properties, and viscoelastic properties of silica-filled tire tread compound according to the processing aid type (TDAE oil, non-functional LqBR) and, silane terminated LqBR) and input timing. In the non-functional LqBR compounds, the 'with TESPT' mixing procedure showed excellent dynamic viscoelastic properties while silane-terminated LqBR compounds showed that the 'after TESPT' mixing procedure was good for 300% modulus and abrasion resistance.

• 복식
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• 제35권
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• pp.135-149
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• 1997

In this thesis the northeast Asian footwear culture are examined,. in order to search the origin It started from the cradle of ancient civilization such as Meospotamia Egypt Indus and ancient China civilization region prior to the northeast Asia. The results are: On account severe intense climates and rough road as well ancient people starts to put the shoes on. Primitive form of ancient footwear put into the two categories: Chinese in the central land begins to put the shoes named Lee. After making contact with nomadic northern races boots named Wha is adopted functionally and taken throughout China. oreans wear the shoes both boots and shoes named Lee. Japanese walked with bare feet and simul-taneously Dagetta was used for rice farming. The changes of footwear is mainly in-fluenced by the factors such as climate con-dition social economic prohibition func-tional elements and aesthetic standards. Cli-mate conditions have influence upon the footwear materials form and foot exposure, The functional elements influenced on the ways of wearing shoes. Decorated patterns and materials of footwear is under the influnece of social economic prohibition and also affected by aesthetic standards(Tab 1-4) In accordance with pattern function materials of footwear the type and characteristics of footwear in China Korea nd japan came out with diversity(Tab 5-9)

• 한국운동역학회지
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• 제27권3호
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• pp.219-227
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• 2017

Objective: The aim of this study was to analyze the effects of bobsleigh shoes on the lower extremity range of motion and start speed lap time and to develop bobsleigh shoes suitable for winter environments and Korean players based on sports science and optimized biomechanical performance. Background: The bobsleigh shoes used in the start section of the sport are one of the most important equipment for improving athletes' performances. Despite the importance of the start section, there are no shoes that are specifically designed for Korean bobsleigh athletes. Thus, Korean athletes have to wear sprint spike shoes instead of bobsleigh shoes to practice the start. Method: The subjects included four bobsleigh athletes from the Gangwon Province Bobsleigh Skeleton Federation. The study selected the bobsleigh shoe type A (company A) and type B (company B). We analyzed the lower extremity range of motion and sprint time (start line to 10 m) using a Motion Analysis System (USA). Results: In the measurement of the time required for the bobsleigh start section (10 m), the type A shoes demonstrated the fastest section record by $2.765{\pm}0.086sec$ and yielded more efficient movements, hip and knee flexion, hip extension, ankle dorsiflexion, plantar flexion, and inversion than the type B shoes. Conclusion: Type A shoes can yield a better performance via effective lower extremity movements in the bobsleigh start section. Application: In the future, functional analysis should be conducted by comparing the upper material properties, comfort, and muscle fatigue of bobsleigh shoes based on the Type A shoes to develop such shoes suitable for Koreans.

• 폴리머
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• 제36권5호
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• pp.622-627
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• 2012

친환경 수성 코팅제의 물성 강화 및 VOCs의 저감 특성을 연구하기 위해서 poly(tetramethylene glycol) 2000, polycarbonate diol 2000, isophorone diisocyanate, dimethylolpropionic acid, 그리고 titanium dioxide를 사용하여 유/무기 하이브리드 수분산 폴리우레탄 코팅제를 제조하였다. R ratio([NCO]/[OH])에 따른 코팅제의 필름 물성 및 무기물의 적용으로 인한 VOCs의 저감 특성에 대해서 연구한 결과 R ratio가 1.5 이상인 경우에서 코팅제로 적합함을 확인하였으며 이는 하드 세그먼트의 영향으로 여겨지며 $TiO_2$의 적용으로 코팅 후 VOCs의 저감 특성을 확인하였다.

• Elastomers and Composites
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• 제58권3호
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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.

• 청정기술
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• 제14권3호
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• pp.193-203
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• 2008

피혁 제조 공정에서 계면활성제는 세정목적, 분산성 그리고 고착성 등을 부여하기 위해 사용되고 있다. 그러나 기존의 피혁 공정에서 사용되고 있는 계면활성제는 친수성기가 다량 포함되어 있어 향후 피혁 시장에서 요구될 것으로 기대되는 내오염성, 내수성, 내구성 통의 고기능성 특성을 재현하는데 문제점이 있다. 본 연구에서는 기존의 탄화수소 계열의 계면활성제의 문제점을 보완하기 위해서, 탄소-불소의 강한 결합에너지로 인한 표면장력 감소, 분산력 증대, 세정효과, 크롬 흡착력 증대 등의 특성을 나타내는 불소계 계면활성제를 제조하였다. 불소계 계면활성제의 사용으로 피혁 제조 공정의 분산성 증대, 침투력 상승 및 결합력을 향상시켜 크롬 흡착률 증가, 탄닝 폐수 배액의 크롬 함량 감소, 생물학적 산소 요구량, 화학적 산소 요구량의 함량 감소 및 물리적 특성이 향상되는 것을 확인하였다.

• 접착 및 계면
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• 제13권1호
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• pp.1-8
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• 2012

EPDM에 카르복시산을 포함하는 아크릴 단량체인 methacrylic acid (MA)가 도입된 grafted EPDM을 합성하여 MA의 grafting ratio가 탄성체의 물성과 다른 고무와의 접착특성에 미치는 영향을 연구하였다. Grafted EPDM의 storage modulus는 특정온도까지는 sulfur로 가교한 EPDM vulcanizate보다 높게 유지되다가 온도가 더 높아지면 2차 결합력이 약해지면서 급격하게 감소되는 것이 관찰되었다. EPDM에 수소결합을 유도할 수 있는 반응기를 도입했을 때 grafted EPDM 분자들 간의 aggregate 형성과 그라프트된 MA의 결정성으로 인해 우수한 기계적 물성을 나타내었다. EPDM 자체는 극성이 낮고 다른 종류의 고무와 분자간 결합력이 약해서 접착이 제대로 이루어지지 않았으며 그라프트된 MA의 함량이 증가할수록 접착강도가 더 높아졌으며 MA의 grafting ratio가 10% 이상일 때에는 접착평가 시 고무시편이 부분적으로 파괴될 정도로 접착력이 우수하였다.

• 한국운동역학회지
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• 제18권4호
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• pp.135-142
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• 2008

본 연구는 9명의 피험자가 2주간 하루 6시간동안 후족부 경사각을 이용한 신발인 S사(社) 신발을 착용하여 보행하였으며 신발을 처음 신었을 때와 2주간 하루 6시간 이상 착용한 후의 데이터를 통해 기존의 운동화와 S사(社) 신발간의 비교를 수행하였다. 1. 기립자세에서의 S사(社) 신발의 착용 시 근전도의 활동인 증가하고 압력분포 중심 움직임은 약 60% 정도 증가하였다. 2. 피험자의 보행 시 S사(社) 신발을 착용하였을 때 신발의 힐 부부분의 $20^{\circ}$ 경사각으로 인해 heel strike 시 발목이 약 $14^{\circ}$ 정도 발등 쪽으로 굽혀짐을 확인하였으며 무릎에서는 이를 보완하기 위해 $2^{\circ}$ 정도 굴곡 됨을 보였다. 3. 이로 인해 최대 지면반력이 보다 빠르게 나타났으나 크기는 변하지 않았다. 4. S사(社) 신발의 착용하고 보행 시 지지기에서 발목과 무릎의 부하는 21-61%의 감소하는 결과를 나타내었다. 결과적으로 S사(社) 신발 착용시 목과 무릎각의 굴곡 각을 증가시켜 보행 시 몸이 곧게 서도록 하였다. 또한 보행 시 부하를 감소시킬 수 있음을 나타냈으나 2주간의 신발 착용으로 인한 신체의 변화는 나타나지 않음을 보였다.