• Proceedings of KHEA Conference
• /
• 2003.10a
• /
• pp.153-153
• /
• 2003

• Proceedings of the Korean Fiber Society Conference
• /
• 2000.04a
• /
• pp.81-84
• /
• 2000

• Resources Recycling
• /
• v.31 no.6
• /
• pp.52-59
• /
• 2022

Calcium silicate based cement (CSC) is a low-carbon cement that emits less CO₂ by up to 70% compared to ordinary Portland cement during its manufacture. Most developed countries have commercialized CSC, whereas Korea is still investigating the manufacturing characteristics and basic properties of CSC. This paper provides a review of methods for manufacturing CSC using domestic raw materials and discusses the possibility of CSC localization based on an evaluation of the basic physical properties of manufactured CSC. The experimental results of this study indicate that the primary mineral components of CSC were CS, C₃S₂ C₂S, and unreacted SiO₂. This suggests the possibility of manufacturing CSC using domestic raw materials that exhibit mineral compositions similar to that of theoretical CSC. The compressive strength of CSC mortar is less than 1MPa at the age of 7 d under wet curing. This implies that hydration does not affect the property development of CSC mortar. Meanwhile, during carbonation curing, the compressive strength is 56 MPa or higher after 7 d, which indicates excellent early strength development. Furthermore, results of Thermogravimetric Analysis Differential scanning calorimetry (TG/DSC) show that a significant amount of CaCO₃ is formed, which is consistent with the results of previous studies. This implies that carbonation is associated significantly with the properties of CSC.

• Composites Research
• /
• v.31 no.1
• /
• pp.30-36
• /
• 2018

The curing behavior of glass fiber reinforced epoxy prepregs based on Bisphenol-A (BPA) was studied by differential scanning calorimetry (DSC). The total heat of reaction(${\Delta}H_{total}=280.3J/g$) was determined based on the results of the dynamic heating scanning experiments. Isothermal experiments were carried out at $110{\sim}130^{\circ}C$, and it was observed that the maximum conversion and the maximum reaction rate were increased as temperature increased. Also Kamal equation was applied to analyze autocatalytic reaction of epoxy prepregs. The higher temperatures, the greater reaction rate constants ($k_1$, $k_2$). Theoretical values were calculated by these reaction rate constants and compared with experimental values. And it was confirmed that they were in reasonable agreement. At the beginning of the reaction, the experimental data and theoretical prediction were shown the same tendency, but at the end of reaction, the experimental data were smaller than theoretical predicted values due to reaction rates controlled by diffusion.

• Composites Research
• /
• v.16 no.1
• /
• pp.34-41
• /
• 2003

A cure process control model was proposed to optimize the curing process of thick filament wound structure. There are two types of smart cure, one is that the boundary conditions of the hollow cylinder are same between inner surface and outer surface, and the other is that inner surface temperature is slightly higher than outer surface to initiate cure reaction from the inner side to the outer side to reduce residual stress.

• Magazine of RCR
• /
• v.16 no.4
• /
• pp.30-36
• /
• 2021

• Polymer(Korea)
• /
• v.37 no.3
• /
• pp.302-307
• /
• 2013

We synthesized aliphatic epoxy acrylate monomer by the reaction of glycerol diglycidyl ether and acrylic acid. The reaction was monitored by FTIR, Raman spectroscopy and $^1H$ NMR. Electron-beam (E-beam) curing behaviors of the synthesized monomer were studied by spectroscopic analysis, glass transition temperature, and tensile properties. We found that curing reaction was complete in a low dosage of ca. 30 kGy. The viscosity of monomer was a low enough for coating without using diluents and the cured sample was highly transparent, indicating that the monomer can be used for an E-beam curable coating material on transparent optical films.

• Journal of Adhesion and Interface
• /
• v.11 no.2
• /
• pp.57-62
• /
• 2010

Photo-curable material can be crosslinked among molecules by light source such as UV and visible light materials. Material properties are controlled by crosslink reaction. Shrinkage is occured during the curing reaction of material structure. Phenomenon of shrinkage stress occurs inside the product and reduce the stability of the product causes problems. Heat shrink the evaluation of the phenomenon has been formalized. But the evaluation of photo shrink is not enough. In this experiment, real-time contract with shrinkage tester phenomena and analysis degree of shrinkage of the material differences. According to the research, experimental results and theoretical analysis of the results were big differences. Shrinkage, especially for a number of different functional groups that were very different theory. These differences are occurred by the molecular structure different and not enough reaction.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.2 no.1
• /
• pp.75-82
• /
• 1988

Epoxy, noticed as a new insulation material tor electrical installation, may become an excellent cured material from the crosslink reaction with some curing agents. The characteristics of cured Epoxy is determined by the kind of the curing agents and the method of lattice formation. The purpose of this paper, varing the process of lattice formation by various surrounding temperatures during the curing process, is to obtain the optimum curing temperature for electrical insulation from the results of investigation on the properties of cured Epoxy. In the experiment, Epoxy was cured at various temperatures between $20[^{\circ}C] and 50^[{\circ}C]$ which differ by $5^[{\circ}C]$, and then examined on the electrical insulation haracteristics as well as the thermal and mechanical stability. As a result, it is concluded that the optimum electrical insulation characteristis and mechanical strength of cured Epoxy can be obtained when cured at a surrounding temperature at $30[^{\circ}C]$.

• Composites Research
• /
• v.17 no.6
• /
• pp.37-43
• /
• 2004

To determine the effect of chain length and chemical structure of linear amine curing agents on thermal and mechanical properties, a standard bifunctional linear DGEBF epoxy resin was cured with EDA and HMDA having amine group at the both ends of main chain in a stoichiometrically equivalent ratio in condition of preliminary and post cure. From this work, the effect of linear amine curing agents on the thermal and mechanical properties is significantly influenced by numbers of carbon atoms of main chain. In contrast, the results show that the DCEBF/EDA system having two carbons had higher values in the thermal stability, density, shrinkage (%), grass transition temperature, tensile modulus and strength, flexural modulus and strength than the DGEBF/HMDA system having six carbons, whereas the DGEBF/EDA cure system had relatively low values in maximum ekothermic temperature, maximum conversion of epoxide, thermal expansion coefficient than the DGEBF/HDMA cure system. These findings indicate that the packing capability (rigid property) in the EDA structure affects the thermal and mechanical properties predominantly. It shows that flexural fracture properties have a close relation to flexural modulus and strength.