• 한국정밀공학회지
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• 제24권12호
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• pp.143-148
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• 2007

Polyethylene is a typical hydrophobic material and it is difficult to bond the polyethylene material with metal material. Thus, it is important to modify the surface of polyethylene material to improve the bonding strength between the polyethylene and the metal materials. In this study, the surface modification of polyethylene material was investigated to improve the interfacial strength between the polyethylene and the steel materials. Polyethylene material was surface-modified in a plasma cleaner using an oxygen gas. Two cases of composites (surface-modified pelyethylene/steel composite and regular (as-received) pelyethylene/steel composite) were fabricated using a secondary bonding method. Shear and bending tests have been performed using the two cases of composites. The results showed that the contact angle did not change much as the modification time increased. However, the contact angle decreased from ${\sim}76^{\circ}\; to\;{\sim}41^{\circ}$ with the modification. The results also showed that the shear strength and the bending strength were improved about 3030 % and 7 %, respectively when the polyethylene was plasma-modified using an oxygen gas.

• Journal of Information Display
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• 제4권1호
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• pp.17-23
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• 2003

A thermoset type anisotropic conductive adhesive film (ACAF) comprising epoxy resin and natural butyl rubber (NBR) as the binder, micro-encapsulated imidazole as the curing agent, and Ni/Au coated polymer bead as a conductive particle has been studied. These films have been prepared to respond to requirements such as improved contact resistance, current status less of than 60 ${\mu}m$ and reliability. These films can also be used for connection between the ITO glass for LCD panel and the flexible circuit board. The curing conditions for the connection were 40, 20 and 15 seconds at 150, 170 and 190 $^{\circ}C$, respectively. The initial contact resistance and adhesion strength were 0.5 ${\Omega}/square$ and 0.4 kg/cm under the condition of 30 kgf/$^{cm}^2}$, respectively. After completing one thousand thermal shock cycling tests between -15 $^{\circ}C$ and 100 $^{\circ}C$, the contact resistance was maintained below 0.7 ${\Omega}/square$. Durability against high temperature (80$^{\circ}C$) and high humidity (85 % RH) was also tested to confirm long-term stability (1000 hrs) of the conduction.

• 한국추진공학회지
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• 제4권3호
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• pp.64-73
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• 2000

본 체결부는 필라멘트 와인딩으로 제작된 연소관, 복합재 쐐기 그리고 알루미늄 내부 링으로 구성된다. 여기서 연소관은 헬리컬 층과 후프 층으로 이루어져 있다. 이러한 복합재 연소관의 성능 향상을 위해 체결부의 설계 변수에 따른 유한 요소 응력 해석이 수행되었다. 이때 접착 층을 난-소성 거동 재질로, 쐐기부와 알루미늄 링간의 접촉 상태는 ABAQUS의 접촉 표면 요소로 모사 되었다. 또한 해석 결과의 정확성을 입증하기 위해 내압에 의한 체결부 밀림 변위와 연소관 몸체의 원주 방향 변형도를 수압 시험과 비교하였다. 쐐기와 알루미늄 링간의 완벽 접착은 쐐기와 연소관간의 접착 층에 높은 전단 변형을 발생시켜 체결부 조기 파괴의 원인이 된다. 쐐기와 알루미늄 링간의 미 접착은 쐐기와 연소관사이의 접착 층 전단 응력을 감소시키는 반면 내부 알루미늄 링의 미끄러짐 거동으로 체결부 복합재의 반경 방향 변형을 증가시켜 파괴를 유발하였다. 그러나 쐐기부와 알루미늄 링간의 미접착 상태에서, 원주 방향 와인딩으로 체결부 지점을 보강한 경우, 알루미늄 링의 미끌어짐이 억제되어 체결부 지점의 복합재 원주 방향 변형값이 감소했다.

• 접착 및 계면
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• 제17권1호
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• pp.1-6
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• 2016

본 연구에서는 신발에 사용되는 부품 중 겉창용 고무 접착에 있어서 buffing, 프라이머 처리와 같은 전처리 공정을 생략하기 위하여, propanamine과 1,6-Hexanediamine와 같은 아민류의 첨가제가 적용된 고무 성형물에 대한 접착특성과 기계적 특성을 고찰하였다. Propanamine과 1,6-Hexanediamine이 첨가되지 않은 고무 시편과 propanamine이 첨가된 고무 시편은 접착성이 발현되지 않았지만 1,6-Hexanediamine이 첨가된 고무 시편의 경우 접착성 효과가 개선되었다. 또한 propanamine과 1,6-Hexanediamine이 첨가된 경우 접촉각이 감소하였으며, 1,6-Hexanediamine이 첨가된 고무 시편이 propanamine이 첨가된 시편에 비해 작은 접촉각을 나타내었다. 고무 표면의 $-NH_2$에 대한 피크는 $1450{\sim}1550cm^{-1}$의 그룹에서 FT-IR 분석 결과로 확인하였다. propanamine과 1,6-Hexanediamine이 첨가된 경우 기계적 특성 저하와 마모 특성이 감소하였다.

• Design & Manufacturing
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• 제10권1호
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• pp.36-40
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• 2016

Connectors transmit electric signals to different parts in compact mobile display products. As products that apply this have become lightweight and smaller in size, there are growing demands for smaller and more integrated connectors, which are internal parts of the products. As a measure to address these demands, there is the planar array connector that minimizes the part by arranging the single-direction BTB connectors to two directions. As connectors become smaller in size and more highly integrated, maintaining intensity to prevent defects during impact and maintaining adhesive force to smoothly transmit electric signals are growing in importance. Thus, in order to identify the impact of concave shaping on improving adhesive power in connector terminal pins as a method to increase the connecting power of planar array connector terminal pins, this study predicted and examined the concave shaping method, number of concave shapes, and the adhesive power according to the size of the concave shape through CAE. For concave shaping, the model that added concave shaping towards the lower part of the connector terminal pin and added spokes for the area pressed down by the concave shaping was 0.74 N, showing increased adhesive force compared to existing models. Furthermore, when applying two concave shaping, rather than just one, there was a tendency for adhesive force to increase. In the case of adhesive power trends according to the size of the concave shaping, adhesive power increased and the width of the concave shape decreased, and the biggest adhesive force trends were shown when the concave shaping depth was 0.01mm.

• 폴리머
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• 제33권4호
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• pp.319-325
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• 2009

편광필름용 점착제를 합성하기 위해 아크릴 단량체를 사용하여 용액중합이 수행되었다. 사용된 아크릴 단량체는 2-ethylhexylacrylate, butylacrylate, acrylic acid였으며, 비율은 점착제의 유리전이온도 $-40^{\circ}C$에 맞추어 2-ethylhexylacrylate: butylacrylate: acrylic acid=25:50:3.5로 하였다. 중합된 점착제에 커플링제를 1 wt% 첨가하였을 때 점착제의 광투과율이 매우 증가하였다. 이러한 현상은 커플링제의 Si-O 결합이 액정셀에 대한 점착력을 향상시킨 결과임을 알 수 있었다. 가교제를 단량체 대비 0.5, 1.0, 1.5 wt% 첨가하였을 매 가교제의 함량이 증가할수록 초기점착력은 감소하고 응집력은 증가하였다. 접촉각 분석에서 가교제의 함량이 증가할수록 표면에너지가 커져 접촉각이 감소하였다. 내열성 측정에서 가교제의 증가나 온도변화에 관계없이 아크릴 점착제는 우수한 내열성을 보였으며 절단면의 관찰에서 가교제의 함량이 증가할수록 절단면이 매끄럽고 깨끗하였다. 종합적으로 점착제의 초기점착력, 응집력, 표면에너지, 절단면의 상태 등을 고려하여 적정 가교제의 투입량을 1.0 wt%로 확정하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.179-180
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• 2002

In this study. the friction transition diagram based on the effect of oxide layer formation on contact surface between TiN coated steel ball and uncoated steel disk was constructed. From the diagram. it can be seen that as the contact load increases. the contact number of cycle at the beginning of oxide layer formation decreases linearly and as the coating thickness increases and the surface roughness of steel disk increases under same contact load. that increases. For the coated ball specimen, a AISI 52100 steel ball was used and AISI 1045 steel was used for the disk counter part.

• Journal of Welding and Joining
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• 제26권1호
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• pp.56-62
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• 2008

In this paper, elastic and plastic adhesion index was very important in deciding adhesive characteristics and varying elastic and plastic index, dimensionless load and pull-off force were analyzed and simulated. Finally, using AFM, experimental surface roughness parameters of substrates and pull-off force between tip and substrates were produced. Using these values, pull-off forces were calculated and were compared with experimental pull-off forces. Through simulation and experiment, it was found that interaction of asperity also had very important influence on adhesive contact.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1151-1154
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• 2005

The size effects for adhesive and frictional characteristics were studied. The specimen was Mica and the AFM tips were SiO2. The radii of SiO2 tip were 280, 380, 930, and 2230 nm on which tribological tests had never been performed. It was found that the adhesive forces and the frictional coefficients increased non-linearly with tip radius. Compared with previous studies at nanoscale and microscale, the results showed behaviors bridging each previous result. It could be said that these results were clues to explain the material behaviors between nanoscale and microscale both in adhesion and friction.

• Tribology and Lubricants
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• 제30권1호
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• pp.36-45
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• 2014

Understanding steel/skin contact phenomena is important for the study of object manipulation in robotics and has been a topic of great interest. In this study, pig skin was taken as a surrogate model for human skin, and its adhesive, friction, and deformation behaviors were measured under various exposure times to air. Indentation, friction, and scratch tests were performed at $25^{\circ}C$ and 45% relative humidity. The influences of adhesion and deformation on the coefficient of friction were characterized; the pig skin was found to be sensitive to the sliding velocity and normal load under the controlled experimental conditions.