• 폴리머
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• 제35권2호
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• pp.141-145
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• 2011

In-mold decoration 포일의 경질 코팅 층에 사용하는 수지를 대상으로 전자빔(electron beam, EB) 경화에 관한 연구를 수행하였다. 시료에 다른 양의 EB를 조사하고 경화 반응 정도를 Fourier transform infrared(FTIR) spectroscopy를 사용하여 관찰하였다. EB 조사선량 증가에 따른 코팅 물성의 변화를 표면 경도와 내마모성을 중심으로 알아보았다. 또한 나노 입자 첨가가 코팅 물성에 미치는 영향을 조사하였다. 본 연구로부터 얻은 실험적 결과는 자외선(ultraviolet, UV) 경화 시스템과 유사한 EB 경화 시스템의 상업적 개발에 이용될 수 있을 것으로 기대된다.

• 대한치과보철학회지
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• 제45권6호
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• pp.743-752
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• 2007

Statement of problem. The aims of the study were to evaluate the effect of current surface conditioning methods on the bond strength of a resin composite luting cement bonded to ceramic surfaces and to identify the optimum cement type. Material and methods. The sixty zirconia ceramic specimens(10 per group) with EVEREST milling machine and 60 tooth block were made. The zirconia ceramic surface was divided into two groups according to surface treatment: (1) airborne abrasion with $110{\mu}m$ aluminum oxide particles; (2) Rocatec system, tribochemical silica coating. The zirconia ceramic specimens were cemented to tooth block using resin cements. The tested resin cements were Rely X ARC, Panavia F and Superbond C&B. Each specimen was mount in a jig of the universal testing machine for shear strength. The results were subjected to 2-way ANOVA and Post hoc tests was performed using Tukey, Scheffe, and Bonferroni test. Results. The mean value of shear bond strength(MPa) were as follows: $$RelyXARC(+Al_2O_3),5.35{\pm}1.69$$; $$RelyXARC(+Rocatec),8.50{\pm}2.13$$; $$PanaviaF(+Al_2O_3),9.58{\pm}1.13$$; $$PanaviaF(+Rocatec),12.98{\pm}1.71$$; $$SuperbondC&B(+Al_2O_3)8.27{\pm}2.04$$; $$SuperbondC&B(+Rocatec),14.46{\pm}2.39$$. There was a significant increase in the shear bond strength when the ceramic surface was subjected to the tribochemical treatment(Rocatec 3M) in all cement groups(P<0.05). Bonding strengths of cements applied to samples treated with $Al_2O_3$ were compared; Rely X ARC showed the lowest values, whereas Panavia F cement showed higher value than that of Superbond C&B group with no statistical significance. When the bond strength of cements with of Rocatec treatment was compared, Rely X ARC showed lowest values. Overall, it was apparent that tribochemical treated Super-Bond possessed higher mean bond strength (14.46MPa; P<0.05) than that of Panavia F cement group with no significance. Conclusions. Silica coating followed silanization(Rocatec treatment) increase the bond strength between resin cement and zirconia ceramic. Panavia F containing phosphate monomer and Superbond C&B comprised of 4-META tend to bond chemically with zirconia ceramic, thus demonstrating higher bond strength compared to BisGMA resin cement. Superbond C&B has shown to have highest value of bonding strength to zirconia ceramic after Rocatec treatment compared to other cement.

• Corrosion Science and Technology
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• 제17권2호
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• pp.74-80
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• 2018

The electronic industries require environmentally-friendly and highly functional materials to enhance the quality of human life. Home appliances require insect repellent steels that work to protect household microwave ovens from incurring damage by insects such as fire ants and cockroaches in tropical regions. Thus, POSCO has developed new types of functional steels, coated with an array of organic-inorganic hybrid composites on the steel surface, to cover panels in microwave ovens and refrigerators. The composite solution uses a fine dispersion of hybrid solution with polymeric resin, inorganic and a pyrethroid additive in aqueous media. The hybrid composite solution coats the steel surface, by using a roll coater and is cured using an induction curing furnace on both the continuous galvanizing line and the electro-galvanizing line. The new steels were evaluated for quality performances, salt spray test for corrosion resistance and biological performance for both insect repellent and antimicrobial activity. The new steels with organic-inorganic composite coating exhibit extraordinarily biological functionalities, for both insect repellent and antimicrobial activities for short and long term tests. The composite-coating solution and experimental results are discussed and suggest that the molecular level dispersion of insecticide on the coating layer is key to biological functional performances.

• The Journal of Advanced Prosthodontics
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• 제3권2호
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• pp.81-84
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• 2011

PURPOSE. The aim of this in vitro study was to investigate the adhesion of initial colonizer, Streptococcus sanguis, on resin, titanium and zirconia under the same surface polishing condition. MATERIALS AND METHODS. Specimens were prepared from Z-250, cp-Ti and 3Y-TZP and polished with $1 {\mu}m$ diamond paste. After coating with saliva, each specimen was incubated with Streptococcus sanguis. Scanning electron microscope, crystal violet staining and measurement of fluorescence intensity resulting from resazurin reduction were performed for quantifying the bacterial adhesion. RESULTS. Surface of resin composite was significantly rougher than that of titanium and zirconia, although all tested specimens are classified as smooth. The resin specimens showed lower value of contact angle compared with titanium and zirconia specimens, and had hydrophilic surfaces. The result of scanning electron microscopy demonstrated that bound bacteria were more abundant on resin in comparison with titanium and zirconia. When total biofilm mass determined by crystal violet, absorbance value of resin was significantly higher than that of titanium or zirconia. The result of relative fluorescence intensities also demonstrated that the highest fluorescence intensity was found on the surface of resin. Absorbance value and fluorescence intensity on titanium was not significantly different from those on zirconia. CONCLUSION. Resin specimens showed the roughest surface and have a significantly higher susceptibility to adhere Streptococcus sanguis than titanium and zirconia when surfaces of each specimen were polished under same condition. There was no significant difference in bacteria adhesion between titanium and zirconia in vitro.

• The Journal of Advanced Prosthodontics
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• 제11권4호
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• pp.223-231
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• 2019

PURPOSE. The purpose of this study was to evaluate the shear bond strength (SBS) of an indirect resin composite (IRC) to the various resin matrix ceramic (RMC) blocks using different surface treatments. MATERIALS AND METHODS. Ninety-nine cubic RMC specimens consisting of a resin nanoceramic (RNC), a polymer-infiltrated hybrid ceramic (PIHC), and a flexible hybrid ceramic (FHC) were divided randomly into three surface treatment subgroups (n = 11). In the experimental groups, untreated (Cnt), tribochemical silica coating (Tbc), and Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) laser irradiation (Lsr) with 3 W (150 mJ/pulse, 20 Hz for 20 sec.) were used as surface treatments. An indirect composite resin (IRC) was layered with a disc-shape mold ($2{\times}3mm$) onto the treated-ceramic surfaces and the specimens submitted to thermal cycling (6000 cycles, $5-55^{\circ}C$). The SBS test of specimens was performed using a universal testing machine and the specimens were examined with a scanning electron microscope to determine the failure mode. Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tukey HSD test (${\alpha}=.05$). RESULTS. According to the two-way ANOVA, only the surface treatment parameter was statistically significant (P<.05) on the SBS of IRC to RMC. The SBS values of Lsr-applied RMC groups were significantly higher than Cnt groups for each RMC material, (P<.05). Significant differences were also determined between Tbc surface treatment applied and untreated (Cnt) PIHC materials (P=.039). CONCLUSION. For promoting a reliable bond strength during characterization of RMC with IRC, Nd:YAG laser or Tbc surface treatment technique should be used, putting in consideration the microstructure and composition of RMC materials and appropriate parameters for each material.

• 대한치과교정학회지
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• 제35권4호
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• pp.302-311
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• 2005

본 연구는 고정원을 강화하는데 사용되는 fiber-reinforced composite (FRC)과 스테인리스강 와이어의 피로 한도를 치아의 생리적 동요도가 허용되는 조건에서 비교하여 FRC의 임상적 유용성을 알아보기 위해 시행되었다. 스테인리스강 와이어군은 각형과 원형 와이어군으로 나누고 FRC군은 uni-directional군과 woven군, 그리고 각각의 군에 있어서 치간 부위에 레진을 코팅한 군과 코팅하지 않은 군으로 나누었다 각 군간의 피로한도를 일반적인 교정치료기간을 재현한 $5{\times}10^5cycle$의 피로한도 내에서 측정하여 비교하였다. 그 결과 스테인리스강 와이어에서는 각형 와이어가 원형 와이어보다 피로한도가 더 높았지만 통계적으로 유의하지는 않았다 (p>0.05) 치간부위를 레진으로 코팅한 FRC와 코팅하지 않은 FRC 모두 uni-directional군이 woven군보다 피로한도가 더 높게 나타났으며 (p<0.05) 그 값은 치간 부위를 레진으로 코팅한 FRC가 코팅하지 않은 FRC보다 더 높게 나타났다(p<0.05). 스테인리스강 와이어와 FRC 모두 임상적으로 유용한 $5{\times}10^5cycle$의 피로한도 내에서는 파절되지 않았기 때문에 둘 다 고정원 강화를 위해 사용하여도 충분하며 또한 심미성이 요구되거나 부가적인 장치의 부착이 필요한 곳에서는 FRC를 사용하여도 충분하리라 생각된다.

• 한국환경보건학회지
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• 제36권3호
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• pp.236-246
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• 2010

In preparative anti-corrosive coating experiments, polyaniline was obtained by reacting an oxidizing agent with the monomer aniline. Further, the primer coating was prepared using a variety of widely-used materials such as urethane resin. For the top coating, epoxy resin and acrylic urethane resin were used. Characteristics of the coatings were assessed according to KS and ASTM specifications, and the structure of the polyaniline was characterized using FT-IR and TGA. For analysis of anti-corrosive properties in salt-spray experiments, measurements of the oxidation state of iron and surface atomic analysis were conducted using XPS and SEM-EDX. Unlike general anti-corrosive coatings which exhibit anti-corrosive effects only as a primer coating, the anti-corrosive coatings using polyaniline as the anti-corrosive pigment showed a marked synergistic effect with the top coatings. In other words, the top coatings not only produce a fine view effect, but also increase, through interaction with the primer coatings, the resistance to diffusion of corrosive factors from the external environment. It was also found that, unlike the heavy metal oxide-forming layer of the passive barrier alone, the polyaniline anti-corrosive pigment oxidized iron at the interface with the iron substrate to form a passive barrier in the oxidic layer, and itself formed a potential barrier layer with anti-corrosive factors from the external environment. Although the passive layer was damaged, the damaged area did not become completely oxidized iron; on the contrary, it showed a tendency to reduction. This can be interpreted such that a passive layer is formed again on the damaged area, and that at the same time there is a tendency to self-healing.

• 대한치과보철학회지
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• 제51권1호
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• pp.27-32
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• 2013

연구 재료 및 방법: 본 연구에서는 간접 레진 수복시에 상아질 접착제와 저점도 레진을 이용한 상아질 레진코팅법을 자가 접착 레진 시멘트에 적용해 전단결합강도가 증가하는지 비교하고 기존의 레진 시멘트와의 전단결합강도 차이가 어떠한지 평가하고자 하였다. 연구 목적: 사람의 발거된 건전한 구치 36개의 치관부를 삭제하고 상아질을 노출시킨 후 3개의 군으로 분류하였다. 1군과 3군은 상아질에 아무런 처리 과정을 거치지 않고 2군만 Clearfil SE bond와 Metafil Flo를 사용해 상아질 레진코팅법을 시행하였다. 24시간의 임시수복 기간을 둔 후 Tescera를 이용하여 제작한 레진 인레이 블록을 1군과 2군에는 Unicem, 3군에는 Panavia F를 사용해 접착하였다. 그 후 증류수에 48시간 동안 보관한 후 전단결합강도를 측정하였다. 측정된 전단결합강도는 one-way ANOVA를 이용하여 비교 분석하였으며 유의한 차이가 있는 경우 Tukey method를 이용하여 multiple comparison를 시행하였다. 결과:상아질에 레진코팅법을 시행한 경우의 Unicem의 결합강도가 상아질에 아무런 처리를 하지 않은 대조군의 결합강도보다 높게 나타났고(P<.0001), 레진코팅을 하지 않고 Panavia F로 접착한 실험군의 결합강도보다 높게 나타났다(P<.0001). 결론: 상아질 레진코팅법은 자가 접착 레진 시멘트의 접착 강도를 증가시켰다.

• 한국응용과학기술학회지
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• 제32권4호
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• pp.623-630
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• 2015

Buffalo leather 표면 코팅에 사용된 폴리우레탄 수지에 glycerol의 함유를 mole % 비로 달리하면서 첨가 하였다. 합성된 폴리우레탄 수지의 기계적 특성은 SEM, FT-IR, UTM 등을 이용하여 측정하였다. 친환경적인 고분자 수지의 관심이 고조됨에 따라 용제의 사용을 최소화한 buffalo leather 코팅에 사용되는 수분산 수지를 합성하였다. 지방족 3가 알콜인 glycerol의 mole % 비가 증가함에 따라 내마모도, 인장강도가 감소함을 알 수 있었다. 반대로 연신율, 내굴곡 물성은 증가함을 알 수 있었다. Toluene을 이용한 내용제성 물성측정 결과에는 glycerol의 mole % 증가에 따른 물성 증감 효과는 없었다.

• Elastomers and Composites
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• 제35권2호
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• pp.89-97
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• 2000

코팅(coating) 산업에서 유기 용제의 방출 감소를 유도하는 환경 규제에 부응하기 위하여 환경 친화적인 수용성 에폭시 수지가 개발되어 왔다. 각 개발 단계를 거칠 때마다 전 단계의 부족한 기술을 보완하기 위하여 새로운 수용성 에폭시 수지가 개발되어 왔다. 처음엔 수용성 에폭시 수지는 콘크리트 공사(masonry)에 주로 사용되었으며, 제2세대에는 콘크리트 공사뿐만 아니라 금속 표면을 보호하는 분야에도 이용되어져 왔다. 제3세대 수용성 에폭시 수지는 내식성(corrosion resistance)을 좋게 하고 휘발성유기물질(volatile organic compound)의 수준을 낮게 해주는 장점이 있어 고성능의 표면 코팅 프라이머(primers)를 제조하는데 이용되고 있다. 이 논문은 당사에서 최근에 개발한 수용성 에폭시 수지를 이용하여 에폭시 프라이머를 배합할 수 있는 중요한 가이드라인을 제시했다. 정확한 에폭시 수지-경화제 시스템을 확립하기 위하여 에폭시 수지와 경화제의 비율을 최적화하는데 중점을 두었다.