• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.371-376
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• 2001

The purpose of this study is to investigate toughening of unsaturated polyester resin by addition of polyuretane liquid rubber. In general, unsaturated polyester resin has strong brittleness in spite of its high strength Therefore; it is difficult to use unsaturated polyester mortar for the place where impact resistance is demanded. In this study, it was evaluated strength and Gf by using to polyurethane liquid rubber. As a result, the toughness of unsaturated polyester mortar was increased by polyuretane liquid rubber.

• 폴리머
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• 제24권4호
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• pp.459-468
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• 2000

유리 또는 아라미드 섬유를 보강재로 사용한 섬유강화 복합재료의 기계적 물성을 증진시키기 위하여 복합재료 적층판을 서로 다른 매트릭스 수지와 섬유를 선정하여 이들의 인장, 굴곡 특성을 조사하였다. 불포화 폴리에스테르와 개질된 표면의 아라미드 섬유 복합재료의 경우, 굴곡 물성의 최대값은 실란 농도가 0.5 wt%일 때 관찰되었다. 불포화 폴리에스테르 수지와 유리섬유 복합재료의 인장 물성은 vinylester계가 가장 높게 나타났으며, 굴곡물성은 isophthalic계가 가장 높은 물성을 나타내었다. 유리섬유와 불포화 폴리에스테르 수지 복합재료의 기계적 물성을 증진시키기 위해 겹침 적층판과 기계적 물성과의 상관 관계에 대해서도 연구가 병행되었다.

• 한국농공학회논문집
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• 제59권6호
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• pp.19-27
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• 2017

This study investigated to predict the compressive strength of unsaturated polyester resin based polymer concrete using the maturity method. The test results show that the development of the compressive strength increased exponentially until an age of 24 hours. After 24 hours, the development of the compressive strength just increased gradually. This test result shows that the strength of unsaturated polyester resin based polymer concrete was developed mainly at the early age. Estimated datum temperature of unsaturated polyester resin based polymer concrete was $-20.67^{\circ}C$ which was much lower than of datum temperature ($-10^{\circ}C$) of Portland cement concrete. Also, this study result shows that the existing maturity index associated with Portland cement concrete was not applicable for polymer concrete because curing time of Portland cement concrete is different clearly with curing time of polymer concrete. The cause of different curing time was that there were different curing mechanisms between Portland cement concrete and polymer concrete. In order to best apply the experimental data to a model, CurveExpert Professional, the commercial software, was used to determine the predictive model regarding the compressive strength of unsaturated polyester resin based polymer concrete. As a result, Gompertz Relation or Weibull Model was an appropriate model as a predictive model. The proposed model can be used to predict the compressive strength, especially, it is more useful when the maturity is in the range between $40^{\circ}C{\cdot}h^{0.4}$ and $900^{\circ}C{\cdot}h^{0.4}$.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.379-382
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• 2003

In this study, methyl methacrylate (MMA)- modified unsaturated polyester mortar, in which the MMA was added to the unsaturated polyester resin, was developed for improving the early-age strength and the workability of the conventional polymer concrete, binder of which was the unsaturated polyester resin. Then the strength properties of the MMA-modified unsaturated polyester mortar were surveyed. The experimental results showed that early-age strength was greater when the MMA contents were increased in the range of $20{\sim}40%$, but the strength rather showed a tendency of decrease when the MMA contents was 50%.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.277-283
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• 2004

The time to ignition, heat release rate characteristics and carbon monoxide yield of fiber reinforced and sandwich phenol resin were investigated with cone calorimeter. The fire characteristics of unsaturated polyester, mostly being applied to the existing passenger train, and phenolic resin were compared. Thermal gravimetric analysis(TGA) was used to monitor the degree of thermal decomposition for the phenolic resin. According to the cone calorimeter data, the time to ignition, heat release rate and CO yield was faster and higher as the external heat flux increase. Under the same heat flux, the time to ignition of sandwich type phenolic resin was shorter than that of fiber reinforced. The result of comparison between unsaturated polyester and phenolic resin was that phenolic resin was shown to have better fire resistance than that of unsaturated polyester.

• 한국농공학회지
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• 제35권2호
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• pp.81-91
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• 1993

This study was performed to evalute effects of fillers on the mixing characteristics and mechanical properties of polymer concrete. Two types of unsaturated polyester polymer and two types of epoxy resin were used as binder material, and the portland cement, a fly ash and heavy calcium carbonate were used as filler. Following conclusions were drawn from the research results. 1. Working life of polymer concrete was not affected by filler types, but affected significantly by polymer types and quantities of hardener and catalysts. 2. Without concerning polymer types, use of heavy calcuim carbonate as filler was the best in improving workability.3. The highest strength was achieved by heavy calcium carbonate in using unsaturated polyester resin and by fly ash in using epoxy resin type.4. Elastic modulus was in the range of 2.05X 10-5~2.6X 10-5gf/cm$^2$, which was approximatly 60% of that of cement concrete. Heavy calcium carbonate with unsaturated polyester resin and fly ash with epoxy resin showed relatively higher elastic modulus.

• 공업화학
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• 제29권2호
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• pp.201-208
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• 2018

올소-타입 불포화폴리에스테르 수지와 이소-타입 불포화폴리에스테르 수지를 합성하여 폴리머 모르타르 복합재료의 폴리머 결합재로 사용하였다. 불포화폴리에스테르 수지의 희석제로는 스티렌 모노머와 아크릴로니트릴을 사용하였고, 경화제로 methyl ethyl ketone peroxide (MEKPO), 가속제로 cobalt octoate (CoOc)를 사용하였다. 수지의 형태와 희석제의 종류에 따라 4종의 불포화폴리에스테르 수지를 제조하여 공시체 제조의 폴리머 결합재로 사용하였다. 폴리머 결합재의 첨가량에 따라 총 16종의 폴리머 모르타르 공시체를 제작하여 내열수성 시험을 행한 후 압축 및 휨강도시험, 세공분석 및 SEM 분석을 실시하였다. 시험결과, 이소-타입 불포화폴리에스테르 수지를 폴리머 결합재로 사용한 공시체가 올소-타입 불포화폴리에스테르 수지를 사용한 공시체보다 더 우수한 강도를 나타내었다. 내열수성시험 후에 측정한 총세공량과 세공의 평균직경은 시험 전에 측정한 값에 비하여 감소되었다. 내열수성시험 전에 관찰한 사진에서 폴리머 결합재와 충전재 및 잔골재가 co-matrix 상으로 견고하게 결합되어 있었으나 내열수성시험 후에 관찰한 사진에서는 폴리머 결합재가 대부분 분해되어 있는 것을 관찰할 수 있었다.

• Carbon letters
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• 제11권4호
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• pp.285-292
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• 2010

Novel unsaturated polyester composites with PAN-based nanofiber, stabilized PAN nanofiber, and carbonized nanofiber webs have been fabricated, respectively, and the effects of the nanofiber web content on their electrical resistivity, the thermal stability, dynamic storage modulus, and fracture surfaces were studied. The result demonstrated that the introduction of just one single layer (which is corresponding to 2 wt.%) of the carbonized nanofiber web to unsaturated polyester resin (UPE) could contribute to reducing markedly the electrical resistivity of the resin reflecting the percolation threshold, to improving the storage modulus, and to increasing the thermal stability above $350^{\circ}C$. The effect on decreasing the resistivity and increasing the modulus was the greatest at the carbonized PAN nanofiber web content of 8 wt.%, particularly showing that the storage modulus was increased about 257~283% in the measuring temperature range of $-25^{\circ}C$ to $50^{\circ}C$. The result also exhibited that the carbonized PAN nanofibers were distributed uniformly and compactly in the unsaturated polyester, connecting the matrix three-dimensionally through the thickness direction of each specimen. It seemed that such the fiber distribution played a role in reducing the electrical resistivity as well as in improving the dynamic storage modulus.

• Transactions on Electrical and Electronic Materials
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• 제13권1호
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• pp.31-34
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• 2012

The addition of nano/micro silica into unsaturated polyester resin (UPR) results in the improvement of the electrical properties of Silica-UPR composites. The surface, volume resistivity, dielectric strength, dissipation factor and dry arc resistivity of nano silica-UPR composites were found to improve significantly. The effects of the nano and micro fillers in UPR have been evaluated. They are presented in this paper. To evaluate the electrical properties of the nano & micro composites, all the measurements were done as per the prescribed methods in ASTM. It was observed that the addition of nano silica improves the electrical properties as compared to micro silica. The better dispersion of silica particles in unsaturated polyester resin enhances the electrical properties of silica-UPR composites.

• 한국농공학회논문집
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• 제51권6호
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• pp.97-103
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• 2009

This study was performed to evaluate the strength and durability properties of recycled polymer concrete using unsaturated polyester resin and recycled aggregates. Unsaturated polyester resin, natural and recycled aggregates and fly ash were used. The mix proportions were determined to satisfy the requirement for the workability and slump according to aggregate sizes (5-10 and 5-25 mm) and unit binder contents (10% and 12%). Tests for the compressive and flexural strength, freezing and thawing and durability for 20% sulfuric solution were performed. The compressive and flexural strength of recycled polymer concrete were in the range of 85~97 MPa and 17.9~20.8 MPa, respectively. The strengths of recycled polymer concrete using recycled aggregate have similar or slightly decreased compared to polymer concrete using natural aggregate. After 300 cycles of freezing and thawing, weight decrease ratio and durability factor of recycled polymer concrete were in the range of 0.13~1.42% and 94~99, respectively.