• 한국기계가공학회지
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• 제20권10호
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• pp.38-43
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• 2021

Photocurable hydrogels are widely used as 3D printing materials in tissue engineering (e.g., scaffold fabrication) as well as optical fibers (or optical sensors) materials. Photocurable hydrogels can control optical and mechanical properties such as chemical or fabrication conditions. In previous research, we introduced a new 3D printing method to fabricate a freestanding overhanging hydrogel structure without supporting structure. This study was measured and analyzed the difference of the mechanical properties of the photocurable hydrogel according to the light intensity using a micro tensile tester. In practically, it was difficult to perform a direct tensile test on a micro (less than 1 mm) size fiber. In this study, the tensile test of the hydrogel fibers could be measured simply and repeatedly using a paper carrier.

• 공업화학
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• 제16권3호
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• pp.342-347
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• 2005

하이퍼브랜치 폴리올(HBP-16, 32, 64)과 acrylic acid로부터 광경화형 하이퍼브랜치 아크릴레이트를 합성하였고, 그 물성을 조사하였다. TGA로 측정한 UV 경화필름의 열안정성은 관능기 수가 증가할수록 좀더 높은 온도로 이동하였다. 또한 아크릴 레이트의 관능기 수가 증가할수록 경도, 내마모성, 인장강도가 우수하였으며, 내후성 테스트에서는 아크릴레이트의 관능기수가 증가할수록 황변 지수 값이 증가하는 결과를 보여주었다.

• 공업화학
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• 제16권1호
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• pp.101-106
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• 2005

Dipentaerythritol 유도체(DPET)와 acrylic acid를 반응하여 6관능 광경화형 변성 폴리아크릴레이트(PA-1)를 제조하였으며, dipentaerythritol 유도체(DPET)에 trimellitic anhydride와 glycidyl methacrylate를 반응시켜 12관능 광경화형 변성 폴리메타아크릴레이트(PA-2)를 제조하고 경화된 물성을 조사하였다. 관능기 수가 증가할수록 중량 평균 분자량은 증가하였으며, TGA (Thermogravimetric Analyzer)로 측정한 UV 경화필름의 열안정성은 (메타)아크릴레이트의 관능기 수가 많을수록 증가하였다. 또한 (메타)아크릴레이트의 관능기 수가 많을수록 경도, 내마모성, 인장강도가 우수하였으며, 내후성 테스트에서는 (메타)아크릴레이트의 관능기 수가 많을수록 황변 지수 값인 yellow index 값이 높아지는 결과를 보여주었다.

• 공업화학
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• 제16권1호
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• pp.93-100
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• 2005

두 종류의 4관능 폴리에스터 폴리올에 대해 trimellitic anhydride와 glycidyl metacrylate를 반응하여 두 종류의 8관능 광경화형 폴리에스터 폴리올 변성 하이퍼브랜치 메타아크릴레이트를 합성하고 광경화된 필름의 물성을 조사하였다. Thermogravimetric analyzer (TGA)로 측정한 UV 경화필름의 열안정성은 HBMA-2 (hyperbranched methacrylate-2)가 HBMA-1 (hyperbranched methacrylate-1)보다 우수하였다. 또한 HBMA-2가 HBMA-1보다 경도, 내마모성, 인장강도가 우수하였으며, 내후성 테스트에서도 HBMA-2의 yellow index 값이 높은 결과를 보여주었다.

• 폴리머
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• 제29권3호
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• pp.237-241
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• 2005

다양한 pentaerythritol 유도체에 대한 trimellitic anhydride와 glycidyl methacrylate를 반응하여 세 종류의 8관능 광경화형 pentaerythritol 변성 초분지형 아크릴레이트를 합성하였다. TGA로 측정한 UV 경화필름의 열 안정성은 pentaerythritol에 ethoxylate 또는 propoxylate가 부가되지 않은 pentaerythritol 단독을 사용한 HBMA-1이 가장 우수하였다. 또한 HBMA-1은 경도, 내마모성 및 인장강도도 우수하였으며, 내후성 테스트에서도 황변 지수인 yellow index 값이 가장 낮은 결과를 보여주었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.491-492
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• 2006

In the microstereolithography which can make 3-D microstructures, curing depth is different according to exposure energy. Curing depth has to be controlled to fabricate complex 3-D microstructures with overhang shape. It becomes increases when the exposure energy increases. And photocurable resin is cured when the exposure energy is bigger than critical energy. So optimal exposure energy has to be found to fabricate overhang structures without being gel. To make thinner layer, UV absorber is used and exposure pattern is changed. In this paper, we find curing characteristics according to exposure energy, and fabricate microstructures with overhang shape.

• Korean Chemical Engineering Research
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• 제60권2호
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• pp.308-312
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• 2022

3D 프린팅 기술은 다양한 재료를 적층하여 구조물을 제작할 수 있으며, 다양한 장점을 바탕으로 최근 제조분야에 널리 활용되고 있다. 특히 고해상도의 액적 기반 3D 프린팅 기술은 주로 광경화성 물질을 사용하여 액적을 증착해 나가며 최종 구조물을 형성한다. 물질의 광경화 특성으로 인해 프린팅 과정에서 발생할 수 있는 빛 노출에 따라 액적의 물성 및 증착 특성이 달라질 수 있다. 이에 본 연구에서는 광경화성 하이드로겔 액적의 빛에너지 조사 조건에 따른 액적의 점도변화 및 표면과의 퍼짐 거동에 관해 실험적으로 관찰 및 분석을 수행하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.422-422
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• 2009

Photocurable inorganic-organic hybrid materials were prepared from colloidal-silica nanoparticles synthesized through the solgel process and using acryl resin. The synthesized colloidal-silica nanoparticles had uniform diameters of around 20 nm, and they were organically modified, using methyl and methacryl functional silanes, for efficient hybridization with acryl resin. The organically modified and stabilized colloidal-silica nanoparticles could be homogeneously hybridized with aeryl resin without phase separation. The successfully fabricated hybrid materials exhibit efficient photocurability and simple film formation due to the photopolymerization of the organically modified colloidal-silica nanoparticles and acryl resin upon UV exposure. The fabricated hybrid films exhibit an excellent optical transmission of above 90% in the visible region as well as an enhanced surface smoothness of around 1 nm RMS roughness. In addition, the hybrid films exhibit improved thermal and mechanical characteristics, much better than those of acryl resin. More importantly, these photocurable hybrid materials fabricated through the synergistic combination of colloidal-silica nanoparticles with acryl resin are candidates for optical and electrical applications.

• 한국정밀공학회지
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• 제23권6호
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• pp.174-179
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• 2006

The curing characteristics of a photocurable resin are critical factors that often decide the ultimate resolution and structural sharpness of a final product fabricated by microstereolithography$(\mu-STL)$. In this study, we investigated the curing characteristics of the FA1260T photopolymer under a visible laser light of 42nm wavelength. Modification of the curing property of the FA1260T is attempted to reduce the cure depth $(D_c)$ by adding a radical quencher to the resin. Also, an organic solvent was used to reduce the resin viscosity for an improvement of the flatness of the liquid surface during layer-by-layer curing. As a result, the minimum $D_c$ has been reduced over a factor of 3 with no abrupt increase. Samples of three dimensional microstructures fabricated using the modified FA1260T are presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.824-828
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• 2000

As production cycle has become more and more shorter, the demand of rapid prototyping technology has increased largely. There are many methods for rapid prototyping technology, such as SLA. SLS, FDM. INK JET, LOM and so on. Of all methods, SLA has been most widely used for fabricating precision parts. But products manufactured by this method have limitation of single color and single material. So the principal purpose of this study is to overcome the limit of single color product. If the internal structure of manufactured product is visible with multi-color characteristic, it is possible to check easily the designed model with reality. In order to give multi-color characteristic to the product, photocurable resin mixed with pigment is used in this study. First, transparency of photocurable resin without pigment is evaluated, and then color characteristic and curing characteristic of the mixture is evaluated changing mixing ratio. Through the basic experiments, it becomes possible to fabricate multi-color 3D prototype without assembly.