• 폴리머
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• 제27권2호
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• pp.152-158
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• 2003

상업적으로 폴리(메틸 메타크릴레이트) (PU) 인조석을 생산하기 위한 두 가지 성형 방법으로 셀 성형법과 벨트 성형법이 있다. 그렇지만 셀 성형법은 생산성 면에서, 벨트 성형법은 설비비 및 생산단가 면에서 각각 단점을 갖고 있다. 그러므로 본 연구에서는 플라스틱 필름을 주형으로 이용하여 PMMA 인조석을 생산하는 새로운 성형 가공 방법에 대한 연구를 통해 벨트 성형법 및 셀 성형법의 단점을 극복하고자 하였다. PMMA 인조석의 생산을 위한 주형용 플라스틱 필름으로는 폴리(비닐 아세테이트) 필름을 사용하였다. 우수한 필름 성형 가공성을 나타낼 뿐만 아니라 경화 후 우수한 기계적 특성을 나타낼 수 있는 메틸 메타크릴레이트 배합물을 제조하고 이를 사용하여 필름 성형법에 의해 PMMA 인조석을 제조하였다. 필름 성형법에 의해 제조된 PMMA 인조석의 성능은 셀 성형법과 벨트 성형법에 의해 각각 제조된 상업용 PMMA 인조석의 성능에 비해 동등 이상의 우수한 성능을 나타내었다. 그러므로 본 연구에서 개발된 필름 성형법은 PMMA 인조석의 생산을 위해 상업적으로도 적용 가능성이 큰 것으로 사료된다.

• Tribology and Lubricants
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• 제25권2호
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• pp.86-95
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• 2009

Adhesion tests were carried out in order to investigate the effect of temperature on the adhesion behavior between a PMMA film and a fused silica lens in the micro scale. For the tests, a microtribometer system was specially designed and constructed. The pull-off forces on the PMMA film were measured under atmospheric condition as the temperature of the PMMA film was increased from 300 K to 443 K and decreased to 300 K. The contact area between the PMMA film and the lens was observed during the test. The adhesion behavior was changed with the change of the PMMA surface state as the temperature increased. In glassy state below 363 K, the pull-off force did not change with the increase of temperature. In rubbery state from 383 K to 413 K, the pull-off force increased greatly as the temperature increased. In addition, the area of contact was enlarged. In viscous state above 423 K, the fingering instability was observed in the area of contact when the PMMA film contacted with the lens. It was also found that the adhesion behavior can be varied with the thermal history of the PMMA film. The residual solvent in the PMMA film could emerge to the PMMA surface due to the heating and reduced the pull-off force.

• 한국전기전자재료학회논문지
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• 제28권11호
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• pp.727-730
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• 2015

In this paper, we fabricated organic compounds detector using the MWCNT/PMMA (multi-walled carbon nanotube / polymethylmethacrylate) composite film. We used polymer film as a matrix material for the device framework, and introduced CNTs for reacting with the organic compounds resulting in changing electrical conductivity. Spray coating method was used to form the MWCNT/PMMA composite film detector, and pattern formation of the detector was done by shadow mask during the spray coating process. We investigated changes of electrical conductivity of the detector before and after the organic compounds exposure. Electrical conductivity of the detector tended to decrease after the exposure with various organic compounds such as acetone, tetrahydrofuran (THF), toluene, and dimethylformamide (DMF). Finally we conclude that organic compounds detection by the MWCNT/PMMA composite film detector was possible, and expect the feasibility of commercial MWCNT/PMMA composite film detector for various organic compounds.

• Tribology and Lubricants
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• 제23권6호
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• pp.288-297
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• 2007

Adhesion and friction tests were carried out in order to investigate the effect of temperature on the tribological characteristics of poly (methylmethacrylate) (PMMA) film using AFM. The pull-off and friction forces on the PMMA film were measured under a high vacuum condition (below $1{\times}10^{-4}$ Pa) as the temperature of the PMMA film was increased from 300 K to 420 K (heating) and decreased to 300K (cooling). Friction tests were also conducted in both high vacuum and air conditions at room temperature. When the temperature was 420 K, which is 25 K higher than the glass transition temperature $(T_g)$ of PMMA, the PMMA film surface became deformable. Subsequently, the pull-off force was proportional to the maximum applied load during the pull-off force measurement. In contrast, when the temperature was under 395 K, the pull-off force showed no correlation to the maximum applied load. The friction force began to increase when the temperature rose above 370 K, which is 25 K lower than the $T_g$ of PMMA, and rapidly increased at 420 K. Decrease of the PMMA film stiffness and plastic deformation of the PMMA film were observed at 420 K in force-displacement curves. After the heating to 420 K, the fiction coefficient was measured under the air condition at room temperature and was found to be lower than that measured before the heating. Additionally, the RMS roughness increased as a result of the heating.

• Tribology and Lubricants
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• 제25권4호
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• pp.207-216
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• 2009

Friction tests were carried out in order to investigate the effects of temperature on the friction and wear behaviors between a PMMA film and a fused silica lens using a microtribometer. The friction forces on the PMMA film were measured under atmospheric condition as the temperature of the film was increased from 300 K to 443 K. The contact area between the film and the lens was observed. The tribological characteristics of the film were significantly changed as the temperature increased. The changes were discussed with the change of the film state from glassy to viscous flow. In addition, the results showed that the friction behavior can be varied with the thermal history of the PMMA film. Residual solvent in the PMMA film could emerge to the PMMA surface due to an additional heating and the solvent on the film surface decreased the friction force.

• 폴리머
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• 제34권2호
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• pp.97-103
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• 2010

6FDA를 포함한 다양한 폴리이미드/MWCNT의 전도성 복합 필름을 제조하기 위하여 MWCNT 표면에 PMMA를 도입하여 복합필름을 제조하였으며 전기 전도성의 변화를 PMMA-g-MWCNT의 농도 변화에 따라 관찰하였다. 6FDA계 폴리이미드계 복합 필름 내의 MWCNT 분산성은 PMMA-g-MWCNT의 경우 분자간의 상호 인력으로 인하여 분산도가 표면 처리하지 않은 MWCNT에 비하여 매우 높음을 확인하였다. 전기 전도도의 거동은 percolation threshold를 통하여 해석하였으며 그 결과 높은 임계 지수와 낮은 임계 농도를 가지는 6FDA-6FpDA/ PMMA-g-MWCNT 복합체가 DABA(diamino benzoic acid)를 포함한 폴리이미드 복합체에 비하여 높은 분산도를 가짐을 확인하였다.

• 소성∙가공
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• 제13권1호
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• pp.59-64
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• 2004

Nano-scratch tests were performed on PMMA thin films spin-coated on a Si substrate using an atomic force microscopy (AFM) with loads ranging form 10nN to 100nN. At low loads, a ridge pattern was formed on the PMMA thin film surface. No wear particles were observed during the pattern-forming mild wear. At high loads, severe wear by plowing occurred, accompanied by wear particles. The film with the highest hardness showed the highest wear resistance. Friction force generated during the scratching was measured, which was closely related with surface deformation of the film. A simple empirical equation to deduce scratch hardness of the film from a linear fixed-distance scratch test was proposed, and scratching-speed dependency of the scratch hardness was displayed.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.89-92
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• 2003

Nano-scratch tests were performed on PMMA thin films spin-coated on a Si substrate using an atomic force microscopy (AFM) with loads ranging from 10nN to 100nN. At low applied loads, a ridge pattern was formed on the PMMA surface. No wear particles were observed during the pattern-forming mild wear. At high applied loads, severe wear occurred accompanied by wear particles. The film with the highest hardness showed the highest wear resistance. Friction force generated during the Scratching was closely related with surface deformation of the film.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.673-674
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• 2006

• 공업화학
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• 제21권3호
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• pp.317-322
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• 2010

본 연구에서는 폴리메틸메타아크릴에이트(polymethylmethacrylate : PMMA) 표면을 친수성으로 개질하기 위하여 불소와 산소의 혼합비율을 변수로 하여 함산소불소화를 실시하였다. 함산소불소화 처리 된 PMMA 표면 및 광투과 특성을 접촉각, 표면자유에너지. X-ray 광전자 분광기(XPS), UV-Vis 분광기를 통하여 분석하였다. 함산소불소화 처리된 PMMA의 표면은 친수화 되어 물 접촉각이 $69^{\circ}$에서 $44^{\circ}$로 감소하였다. 또한 PMMA의 표면자유에너지가 $46\;mN\;m^{-1}$ 에서 $58\;mN\;m^{-1}$로 증가하였다. 이는 함산소불소화를 통한 PMMA표면에 친수성 관능기의 형성으로 기인하였다. 또한, XPS 분석 결과로부터 함산소불소화 처리 시 PMMA 표면에 O/C비율이 증가하였고, 불소 부분압이 증가할수록 친수성을 나타내는 C-OH 결합의 �t량이 6.7%에서 24.8%로 증가하는 것을 알 수 있었다. 본 함산소불소화 조건(상온, 총압 1 bar, 불소 및 산소 혼합비 5 : 5)에서는 함산소불소화가 PMMA의 광투과 특성에 영향을 주지 않으면서도 그 표면특성이 개선됨을 관찰할 수 있었다. 이 결과로부터 함산소불소화는 PMMA 표면을 친수성으로 개질하는데 효과적인 방법으로 기대된다.