• 한국응용과학기술학회지
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• 제25권1호
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• pp.1-14
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• 2008

To prepare weather-resistant modified silane acrylic resin coatings for an architectural purpose, tetrapolymers were synthesized by radical polymerization. 3-Methacryloxypropyltrimethoxysilane (MPTS) as a silicone monomer and n-butyl acrylate, methyl methacrylate, and n-butyl methacrylate as acrylic monomers were used. The composition of monomers was adjusted to fix the glass transition temperature of acrylic polymer for $20^{\circ}C$. The composition of MPTS in the synthesized polymer were varied from 10 wt% to 30 wt%. On the basis of synthesized resin amber paints were prepared and their physical properties and effects on weatherability were examined. The presence of MPTS in modified silane acrylic resins generally resulted in low molecular weight and broad molecular weight distribution, and also lowered the viscosity of the copolymers. The coated films prepared from these resins showed good and balanced properties in general. Adhesion to the substrate was outstanding in particular. Weatherability tests were carried out in three different types such as outdoor exposure, QUV, and SWO. The test results showed that the modified silane acrylic resins containing 30 wt% of MPTS had superior weathering properties.

• 한국응용과학기술학회지
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• 제18권1호
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• pp.29-39
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• 2001

An acrylic resin was synthesized with several monomers, styrene(St), 2-hydroxyethyl methacrylate(2-HEMA), n-butyl acrylate, methyl methacrylate, and acetoacetoxyethl methacrylate(AAEM) to prepare a high-solid coatings. Then, a high-solid acryl/melamine coatings was prepared by curing the acrylic resin with a curing agent, hexamethoxymethylmelamine(HMMM). The curing behavior of the acrylic resin with HMMM was investigated by the Ozawa method using DSC. For AAEM/HMMM and 2-HEMA/HMMM curing reactions, activation energies were 33.01 and 27.12 kcal/mol and frequency factors were $9.54{\times}10^{15}}$ and 1.53{\times}10^{13} $min^{-1}$, respectively. From the results, it was found out that 2-HEMA showed higher reactivity with the curing agent than AAEM.

• 폴리머
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• 제30권2호
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• pp.135-139
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• 2006

인체 뼈의 주성분인 수산화인회석(hydroxyapatite, HAP)이 충전된 고분자 복합체를 제조하고 이들의 치과적 물성을 분석하여 치과용 수복재료로의 응용성을 확인하고자 하였다. 복합체 제조에 사용된 기질인 아크릴계 단량체는 가시광선으로 경화시켰다. 실험 결과, HAP는 무게비로 65%까지 첨가되었으며 중합깊이는 6.0 mm 정도로서 일반적 치과용 수복재료로의 응용이 가능함을 확인하였다. 제조된 고분자 복합체의 중합전환율은 HHP 첨가량이 늘어날수록 약간 감소하였으며 중합수축률은 HAP 변화량에의 의존성이 거의 없었다. 복합체의 기계적 물성은 HAP함량이 증가할수록 간접인장강도는 증가하였고 굴곡강도는 큰 변화가 없었다. 그러나 그 값들은 치의학에서 규정한 값들을 상회하여 치과용 재료로의 응용 가능성이 매우 높음을 확인할 수 있었다.

• 보존과학연구
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• 통권20호
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• pp.121-137
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• 1999

Among pigment used at work of Dan-Chung, Emerald Green is specific illuminating fluorescent light of green. It is very difficult to change other organic or inorganic pigment. All of the internal high class pigment has rare light. But Emerald Green is superior to fresh color and stability out of industrial chemical products. It forms over 50% of quantity and importance of a pattern painting. Emerald Green prohibited to produce because of its toxicpollutants, so required to changing pigment development. It is characterized to excellent color, convenient work, economical, against-sunlight, against-air pollutant and durability. The result of a test is follows; 1. We are investigated into producing internal natural Emerald Green, import external pigment and industrial synthesis method etc. but unable to buy because of its toxic pollutant. 2. We are made six samples by yellowish and green is hpigment mixing. We tested on against sunlight and air pollutant. The best mixing ratio is follows. Titanium Dioxide R760 : 18g- Chalk, White Wash : 10g- Permanent Yellow : 7g- Cyanine Green : 8g- Chrome Yellow : 3g- Resin(Vehicle) : Acryl Emulsion(Styrene + 2-Ethyl HexylAcrylate + Methyl Meth Acrylate) 8%

• 마이크로전자및패키징학회지
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• 제23권3호
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• pp.15-20
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• 2016

In an effort to overcome the weakness of aerogel, polymer aerogels have been prepared by copolymerizing the different types of monomers through sol-gel process. Polymerizing the successive phase of a high internal phase emulsion, which has interconnected porous structure, porous polymer aerogel can be manufactured. In this paper, we use the styrene/divinylbenzene chain as a basic monomer structure, and additionally use 2-ethylhexyl methacrylate (2-EHMA) or 2-ethylhexyl acrylate (2-EHA) as monomers for distinguishing the visible mechanical properties of synthesized polymer aerogel. We can observe the different tendency of polymer aerogels by kinds of monomer or ratio. Flexibility and microstructure can be changed by the types of monomer. EHA polymer aerogel shows high flexibility and thin microstructure, and EHMA polymer aerogel shows high hardness and thick microstructure. EHA/EHMA polymer aerogel shows the intermediate nature between them. By utilizing the mechanical properties of three types of polymer aerogels to adequate situation or environment, polymer aerogels could be used as drug agent, ion exchange resin, oil filter and insulator, and so on.

• 폴리머
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• 제38권2호
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• pp.138-143
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• 2014

${\alpha},{\omega}$-Hydroxypropyl기를 갖는 polydimethylsiloxane을 합성하고 이를 hexamethylenediisocyanate(HDI)의 고리화 반응으로 제조된 HDI trimer와 반응시켜 말단에 이소시아네이트 기를 갖는 PDMS 변성 urethane(PSU)을 제조하였다. 이소시아네이트기를 갖는 PSU와 2-hydroxyethylmethacrylate를 urethane 반응으로 acrylate기를 갖는 PDMS 변성 urethane base 수지(PSUA)를 제조하였으며, 이를 FTIR, NMR로 구조를 확인하여 분석하였다. 제조한 base 수지에 아크릴계 경화제, 광 개시제, 용매들을 혼합하여 코팅 액을 제조하였으며 이를 PET 필름에 도포하고 자외선으로 조사하여 고경도의 유연성을 갖는 코팅 막을 얻었다. 얻어진 코팅 막의 광 투과도는 89.7%, 연필경도는 3H, 접촉각은 $88^{\circ}$였다.

• 폴리머
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• 제28권3호
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• pp.273-280
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• 2004

고형분 80%인 아크릴수지 (에틸 메타크릴레이트-2-히드록시프로필 메타크릴레이트-노르말부틸 아크릴레이트-아크릴산 : EHBC)를 합성한 후 이를 헥사메틸렌 디이소시아네이트-뷰렛 경화제로서 상온경화시켜 고 고형분 도료 (에틸 메타크릴레이트-2-히드록시프로필 메타크릴레이트-노르말부틸 아크릴레이트-아즈릴산/헥사메틸렌 디이소시아네이트-뷰렛 : EHBCN)를 제조하였다. 진동자법에 의한 점탄성 측정에서 제조된 도료인 EHBCN-4 (EHBC-4 정적 $T_{g}$ $0^{\circ}C$)와 EHBCN-7 (EHBC-7 : 정적 $T_{g}$ 3$0^{\circ}C$)의 경화시간은 6.2시간과 4.5시간으로, 또한 경화된 도막의 동적 $T_{g}$ 는 $14^{\circ}C$ 와 $39^{\circ}C$로 각각 나타났다. 도막 물성 중 접착력과 굴곡성은 카프로락톤 아크릴레이트 단량체 성분이 함유된 EHBCN쪽의 물성이 현저히 좋게 나타나, 카프로락톤 아크릴레이트 성분이 접착력과 굴곡성을 증진시켰음이 입증되었다.

• The Journal of Advanced Prosthodontics
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• 제12권4호
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• pp.218-224
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• 2020

PURPOSE. The objectives of this study were to evaluate the fracture strength and fracture patterns of provisional crowns fabricated from different materials and techniques after receiving stress from a simulated oral condition. MATERIALS AND METHODS. A monomethacrylate-based resin (Unifast Trad) and a bis-acryl-based (Protemp 4) resin were used to fabricate provisional crowns using conventional direct technique. A milled monomethacrylate resin (Brylic Solid) and a 3D-printed bis-acrylate resin (Freeprint Temp) were chosen to fabricate provisional crowns using the CAD/CAM process. All cemented provisional crowns (n=10/group) were subjected to thermal cycling (5,000 cycles at 5°-55℃) and cyclic occlusal load (100 N at 4 Hz for 100,000 cycles). Maximum force at fracture was tested using a universal testing machine. RESULTS. Maximum force at fracture (mean ± SD, N) of each group was 657.87 ± 82.84 for Unifast Trad, 1125.94 ± 168.07 for Protemp4, 953.60 ± 58.88 for Brylic Solid, and 1004.19 ± 122.18 for Freeprint Temp. One-way ANOVA with Tamhane post hoc test showed that the fracture strength of Unifast Trad was statistically significantly lower than others (P<.01). No statistically significant difference was noted among other groups. For failure pattern analysis, Unifast Trad and Brylic Solid showed less damage than Protemp 4 and Freeprint Temp groups. CONCLUSION. Provisional crowns fabricated using the CAD/CAM process and the conventionally fabricated bis-acryl resins exhibited significant higher fracture strength compared to conventionally fabricated monomethacrylate resins after the aging regimen. Therefore, CAD/CAM milling and 3D printing of provisional restorations may be good alternatives for long term provisionalization.

• 한국정밀공학회지
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• 제25권2호
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• pp.123-130
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• 2008

A 3D structure production method for microstereolithography is a useful way that produces complex structures with flexible processes and low cost. Several UV curable resins were blended and the optimal resin for micro-lens fabricate was selected through viscosity, workability and transmission tests. It consists of 1, 6 - Hexanediol diacrylate with 15 Apha and Isobornyl acrylate for reducing some shrinkage. When fabricating a micro-lens array on large surface, some distortion of shape occurred because of the surface tension between cured part. To overcome this problem, the optimal processing conditions were derived from considering amount of the resin and surface tension. Large surface Micro-lens array, which are a type of elliptical convex and consist of 18,000 micro-lens in the range of 2cm*2cm were fabricated. The focal length to the X-axis and Y-axis were calculated. To verify the performance, measure an energy distribution of transmitted light from the Large surface Micro-lens array.

• 한국응용과학기술학회지
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• 제20권3호
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• pp.221-229
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• 2003

A copolymer ${\sim}$550cps ; $M_n$, 2590${\sim}$2850 ; and conversion, 82${\sim}$89%, respectively. It was found from the plotting of $T_g$ versus viscosity and $T_g$ versus molecular weight that viscosity increased with $T_g$ while number averaged molecular weight decreased with increasing $T_g$.