• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.43.1-43.1
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• 2009

Bone plate는 골절된 뼈의 골 유합을 지지하기 위해서 정형외과, 신경외과, 성형외과 및 치과 등에서 널리 사용되고 있다. 하지만 기존의 bone plate는 대부분 금속으로 제작되어 있어 장기간 이식에 따른 부식 및 천연골 강도저하 등으로 인해 1~2년 후 재수술을 해야 하는 문제점을 갖고 있다. 본 연구에서는이런 금속 bone plate의 단점을 개선하고자 생체적합성이 우수한 생분해성 고분자 bone plate를 제작하였다. 사용된 고분자는 생체적합성과 생분해성이우수한 PVA(polyvinly alcohol)와 강도를 유지하기 위한 PMMA(poly methyl methacrylate)를 사용였다. Electrospinning 법으로 PVA와 PMMA fibrous mat를 제작하여 각 mat를 적층시킨 후 열압착을 하여 강도를 증가시킨 PMMA/PVA Mutlilayer bone plate을 제작하였다. 제작된 PMMA/PVA Mutlilayer bone plate의 생체적합성 평가를 위해 MTT assay, 생분해 특성을 관찰하기 위해 Micro-CT와 SBF(simulated body fluid) 내에서의 용해도를 관찰하였다. 또한조골세포의 부착과 분화에 미치는 영향을 SEM(scanning electron microscope)을통해 관찰하였고, 조골세포의 유전자 발현에 미치는 영향을 RT-PCR을통해 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.382-383
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• 2007

PMMA plate with nano-sized pattern was synthesized on anodized aluminum oxide template by bluk polymerization method. Anodized aluminum oxide was used as a template to synthesize the PMMA plate with nano-sized pattern. The polymerization of MMA was performed at $75-79^{\circ}C$. It is verified from SPM results that the nano-sized pattern on synthesized PMMA plate was well transferred from that of anodized aluminum oxide template.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.414-415
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• 2007

PMMA light guiding plate with nano pattern was fabricated by nano imprinting technology. Silicon mold was fabricated by conventional photolithography. A nickel stamper was fabricated by electroplating process using silicon mold. Nano imprinting was performed on PMMA plate at $140^{\circ}C$ under pressure of 20kN. The nano pattern on PMMA plate was investigated using FE-SEM.

• 대한방사선치료학회지
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• 제19권1호
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• pp.19-26
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• 2007

목 적: Ir-192 고선량율 근접치료(HDR Brachytherapy)선원에 대한 다양한 측정절차의 효율을 서로 비교할 것이며, 측정 장비의 추가 구입 없이 대안으로 새롭게 만든 PMMA (polymethylmethacrylateplastics: $C_5H_8O_2$) plate phantom에 대한임상에서의 적합성과 유용성을 알아 보았다. 대상 및 방법: 세 가지 형태(Well type chamber, Source calibration jig, PMMA plate phantom)의 측정 시스템을 이용하여 측정값을 비교하였다. Source calibration jig와 PMMA plate phantom을 사용 했을 때에는 Farmer type chamber를 이용하여 측정하였으며, 각각 5회씩 측정하여 제조업체의 측정치와 비교하였다. 또한 새로운 선원을 교환 할 때마다 제조업체로부터 선원과 함께 제공되는 제조업체의 측정치를 본 연구의 측정치와 비교하여 방사능의 정확도를 평가 하였다. 결 과: Well type chamber, Source calibration jig, PMMA plate phantom를 사용한 Ir-192 선원의 측정결과 제조업체 측정치와의 상대오차에 대한 RMS (Root Mean Square)값은 Well type chamber에서 0.6%, Source calibration jig에서 1.57%, PMMA plate phantom에서는 2.1%를 나타내었다. 또한 평균 오차에 대한 편차는 Well type chamber에서 $-0.2{\pm}0.5%$, Source calibration jig에서 $0.97{\pm}1.23%$, PMMA plate phantom에서는 $-0.89{\pm}1.87%$를 나타내었다. 결 론: 본 연구를 통해 실험한 세 가지 형태(Well type chamber, Source calibration jig, PMMA plate phantom)의 측정 시스템의 결과에서 나타난 것처럼, Well type chamber를 이용한 측정결과가 가장 우수하게 나타났다. 또한 측정 장비를 구입하지 않고 대안으로 새롭게 만든 PMMA plate phantom의 결과 권고안 ${\pm}5%$를 초과하지 않으므로 임상에서 유용하게 사용 할 수 있을 것이라 생각되어진다.

• 제어로봇시스템학회논문지
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• 제14권5호
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• pp.420-425
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• 2008

PMMA light guiding plate with nano-sized pattern was fabricated using anodized aluminum oxide membrane as a template for nano imprint lithography. Nano-sized pore arrays were prepared by the self-organization processes of the anodic oxidation using the aluminum plate with 99.999% purity. Since the aluminum plate has a rough surface, the aluminum plate with thickness of 1mm was anodized after the pre-treatments of chemical polishing, and electrochemical polishing. The surface morphology of the alumina obtained by the first anodization process was controlled by the concentration of electrochemical solution during the first anodization. The surface morphology of the alumina was also changed according to temperature of the solution during chemical polishing performed after first anodization. The pore widening process was employed for obtaining the one-channel with flat surface and height of the channel because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of two-channel with rough surface. It is shown from SPM results that the nano-sized pattern on PMMA light guiding plate fabricated by nano imprint lithography method was well transferred from that of anodized aluminum oxide template.

• 한국재료학회지
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• 제20권6호
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• pp.312-318
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• 2010

Multilayer Poly methyl methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates were fabricated using electrospinning and in vitro investigations were carried out for pre-clinical biocompatibility studies. The initial cellular cytotoxicity of the methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay using fibroblast-like L-929 cells. Cellular adhesion and differentiation studies were carried out using osteoblast-like MG-63 cells. As simulated body fluid (SBF) contains the same ionic concentration of body fluid and any bioactive material tends to deposit bone-like apatite on the samples surfaces into the SBF, in vitro bioactivity of the multilayer bone plates were investigated using SBF. We also studied the internal organization and tensile strength of the multilayer PMMA/PVA bone plates using micro-computed topography (${\mu}$-CT) and universal testing instrument (UTI, Korea) respectively. The cellular cytotoxicity study with MTT confirmed that the cellular viability was 78 to 90% which indicates good cyto-compatibility. Scanning electron microscopic findings revealed a good attachment and adhesion phenomenon of MG-63 cells onto the surfaces of the samples. Cellular differentiation studies also showed that osteogenic differentiation was switched on in a timely manner and affirmed along with that of the control group. Bone-like apatite formation on the surfaces was confirmed within 14 days of SBF incubation. Initial organizations of the multilayer PMMA/PVA bone plates were characterized as dense and uniform. The tensile strength of the post-pressing electronspun mat was higher than that of the pre-electronspun mat. These results suggest that a multilayer PMMA/PVA bone plate system is biocompatible, bioactive and a very good alternative bone plate system.

• 제어로봇시스템학회논문지
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• 제14권4호
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• pp.332-335
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• 2008

PMMA light guiding plate with nano pattern was fabricated by nano imprint lithography method. A silicon mold for electroplating of nickel was fabricated by conventional photolithography process. A nickel stamp for nano imprint lithography was fabricated by electroplating process using silicon mold. The nano imprint lithography was performed on PMMA plate at $140^{\circ}C$ under pressure of 20kN. The nano pattern on PMMA plate was investigated using FE-SEM. It is shown that the patterns were well transferred for several steps and the nano imprint lithography method could be applied for fabricating patterns of light guiding plate.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1323-1324
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• 2013

• 접착 및 계면
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• 제6권3호
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• pp.1-9
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• 2005

본 연구에서는 대기압 플라스마 공정으로 표면 처리 시 PMMA 시편의 표면 자유 에너지에 영향을 주는 인자인 radio frequency (RF) 플라즈마 전압(W), 처리시간(s), 방전 글로우와 시료와의 간격(mm) 그리고 아르곤 가스의 유량(LPM)에 대해 실험 계획법(Design of Experiment, DOE)을 적용한 최적화 실험을 실시하였다. 실험 결과, PMMA의 표면 자유 에너지 증가에 가장 큰 영향을 미치는 인자는 플라즈마 방전 글로우와 시료와의 간격(mm), 처리시간(t), 플라즈마 전압(W) 순으로 확인되었다. 또한 표면에 상호 영향을 미치는 플라즈마 전압과 처리시간에 대한 복합매개변수 형태의 power dose (J)에 따른 의존성을 확인했을 때 1500 J에서 최대의 표면 에너지 증가를 보임을 확인하였다. XPS, AFM 분석을 통해 플라즈마 처리 후 PMMA 표면에 새로운 관능기의 도입과 표면 거칠기 변화를 관찰하였다. 플라즈마 처리에 의한 PMMA plate의 표면 자유 에너지의 변화는 플라즈마 처리에 의한 관능기의 도입과 표면적의 변화에 영향을 받는 것으로 생각된다.

• 소성∙가공
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• 제17권8호
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• pp.633-642
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• 2008

It's important to measure quantitative properties about thermal-nano behavior of polymer for producing high quality components using Nanoimprint lithography process. Nanoscale indents can be used to make the cells for molecular electronics and drug delivery, slots for integration into nanodevices, and defects for tailoring the structure and properties. In this study, formability of polymethylmetacrylate(PMMA) and polycarbonate(PC) were characterized Polymer has extreme variation in thermo mechanical variation during forming high temperature. Because of heating the polymer, it becomes softer than at room temperature. In this case it is particularly important to study high temperature-induced mechanical properties of polymer. Nanoindenter XP(MTS) was used to measure thermo mechanical properties of PMMA and PC. Polymer was heated by using the heating stage on NanoXP. At CSM(Continuous Stiffness Method) mode test, heating temperature was $110^{\circ}C,120^{\circ}C,130^{\circ}C,140^{\circ}C$ and $150^{\circ}C$ for PMMA, $140^{\circ}C,150^{\circ}C,160^{\circ}C,170^{\circ}C$ and $180^{\circ}C$ for PC, respectively. Maximum indentation depth was 2000nm. At basic mode test, heating temperature was $90^{\circ}C$ and $110^{\circ}C$ for PMMA, $140^{\circ}C,160^{\circ}C$ for PC. Maximum load was 10mN, 20mN and 40mN. Also indented pattern was observed by using SEM and AFM. Mechanical properties of PMMA and PC decreased when temperature increased. Decrease of mechanical properties from PMMA went down rapidly than that of PC.