• Title/Summary/Keyword: Thermal curing

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Nondestructive Interfacial Evaluation and Cure Monitoring of Carbon Fiber/Epoxyacrylate Composite with UV and Thermal Curing Using Electro-Micromechanical Technique (Electro-Micromechanical 시험법을 이용한 탄소 섬유 강화 에폭시아크릴레이트 복합재료의 자외선과 열경화에 따른 경화 모니터링 및 비파괴적 계면 평가)

  • 박종만;공진우;김대식;이재락
    • Polymer(Korea)
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    • v.27 no.3
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    • pp.189-194
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    • 2003
  • Interfacial evaluation, damage sensing and cure monitoring of single carbon fiber/thermo setting composite with different curing processes were investigated using electro-micromechanical test. After curing, the residual stress was monitored by measurement of electrical resistance and then compared to various curing processes. In thermal curing case, matrix tensile strength, modulus and interfacial shear strength were higher than those of ultraviolet curing case. The shrinkage measured during thermal curing occurred significantly by matrix shrinkage and residual stress due to the difference in thermal expansion coefficient. The apparent modulus measured in the thermal curing indicated that mechanical and interfacial properties were highly improved. The reaching time to the same stress of thermal curing was faster than that of UV curing case.

Nondestructive Damage Sensing and Cure Monitoring of Carbon Fiber/Epoxyacrylate Composite with UV and Thermal Curing using Electro-Micromechanical Technique (Electro-Micromechanical 시험법을 이용한 탄소섬유 강화 Epoxyacrylate 복합재료의 UV 및 열경화에 따른 비파괴적 손상 감지능 및 경화 Monitoring)

  • Kong, Jin-Woo;Kim, Dae-Sik;Park, Joung-Man;Lee, Jae-Rock
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2002.10a
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    • pp.261-264
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    • 2002
  • Interfacial evaluation, damage sensing and cure monitoring of single carbon fiber/thermosetting composite with different curing processes was investigated using electro-micromechanical test. After curing, residual stress was monitored by measurement of electrical resistance (ER) and then it was compared to correlate with various curing processes. In thermal curing, curing shrinkage appeared significantly by matrix shrinkage and residual stress due to the difference in thermal expansion coefficient (TEC). The change in electrical resistance (ΔR) on thermal curing was higher than that on ultraviolet (UV) curing. For thermal curing, apparent modulus was the highest and reaching time until same strain was faster. So far thermal curing shows strong durability on the IFSS after boiling test.

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Cure Properties of Novel Epoxy Resin Systems for WLP (Wafer Level Package) According to the Change of Hardeners (경화제 변화에 따른 WLP(Wafer Level Package)용 신규 Epoxy Resin System의 경화특성)

  • Kim, Whan Gun
    • Journal of the Semiconductor & Display Technology
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    • v.21 no.2
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    • pp.57-67
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    • 2022
  • The curing characteristics of naphthalene type epoxy resin systems according to the change of curing agent were investigated to develop a new next-generation EMC(Epoxy Molding Compound) with excellent warpage characteristics, low thermal expansion, and excellent fluidity for WLP(Wafer Level Package). As epoxy resins, DGEBA, which are representative bisphenol type epoxy resins, NE-16, which are the base resins of naphthalene type epoxy resins, and NET-OH, NET-MA, and NET-Epoxy resins newly synthesized based on NE-16 were used. As a curing agent, DDM (Diamino Diphenyl Methane) and CBN resin with naphthalene moiety were used. The curing reaction characteristics of these epoxy resin systems with curing agents were analyzed through thermal analysis experiments. In terms of curing reaction mechanism, DGEBA and NET-OH resin systems follow the nth curing reaction mechanism, and NE-16, NET-MA and NET-Epoxy resin systems follow the autocatalytic curing reaction mechanism in the case of epoxy resin systems using DDM as curing agent. On the other hand, it was found that all of them showed the nth curing reaction mechanism in the case of epoxy resin systems using CBN as the curing agent. Comparing the curing reaction rate, the epoxy resin systems using CBN as the curing agent showed a faster curing reaction rate than them with DDM as a hardener in the case of DGEBA and NET-OH epoxy resin systems following the same nth curing reaction mechanism, and the epoxy resin systems with a different curing mechanism using CBN as a curing agent showed a faster curing reaction rate than DDM hardener systems except for the NE-16 epoxy resin system. These reasons were comparatively explained using the reaction rate parameters obtained through thermal analysis experiments. Based on these results, low thermal expansion, warpage reduction, and curing reaction rate in the epoxy resin systems can be improved by using CBN curing agent with a naphthalene moiety.

A Study on the Mix Design and the Control System of Thermal Crack for High Quality Mass Concrete (고품질 매스콘크리트 시공을 위한 배합설계 및 온도균열제어 시스템에 관한 연구)

  • Kim, Sun-Gu;Lee, Sang-Soo;Won, Cheol;Park, Sang-Joon;Kim, Dong-Seok
    • Journal of the Korea Institute of Building Construction
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    • v.1 no.2
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    • pp.174-178
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    • 2001
  • This study was performed to control the thermal crack of the mat footing slab in the multi-purposed buildings. In this study, we executed the mixing design of concrete to satisfy the workability and the quality according to the site conditions. And, we evaluated quantitatively about the possibility of thermal crack by using hydration heat analysis system. Finally, we proposed the optimal mixing conditions, curing methods and curing period which all factors are considered. As a result, the optimal mixing conditions were : W/B 41%, unit binder 375kgf/$\textrm{m}^3$, FA replacement ratio 20%. Lowest thermal stress was 22.0kgf/$\textrm{cm}^2$ and at that time thermal crack index was over 1.5, when the coefficient of thermal conductivity was lowest among the curing conditions. And, the total curing time was estimated at 6.7 days according to curing steps.

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A Study on the Mix Design and the Control of Thermal Crack of Mass Concrete (매스콘크리트의 배합설계 및 온도균열제어에 관한 연구)

  • Lee, Sang-Soo;Won, Cheol;Park, Sang-Joon;Kim, Dong-Seok
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.533-538
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    • 2001
  • This study was peformed to control the thermal crack of the mat footing slab in the multi-purposed buildings. In this study, we executed the mixing design of concrete to satisfy the workability and the quality according to the site conditions. And, we evaluated quantitatively about the possibility of thermal crack by using hydration heat analysis system. Finally, we proposed the optimal mixing conditions, curing methods and curing period which all factors are considered. As a results, the optimal mixing conditions were : W/B 41%, unit binder 375kg/$cm^{2}$, FA replacement ratio 20%. Lowest thermal stress was 22.0kgf/$cm^{2}$ and at that time thermal crack index was over 1.5, when the coefficient of thermal conductivity was lowest among the curing conditions. And, the total curing time was estimated at 6.7 days according to curing steps.

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Thermal Curing Property of Silicone Encapsulant Containing Quantum Dot Surrounded by Various Types of Ligands

  • Lee, Chae Sung;Kim, BeomJong;Jeon, Seongun;Han, Cheul Jong;Hong, Sung-Kyu
    • Bulletin of the Korean Chemical Society
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    • v.34 no.12
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    • pp.3787-3789
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    • 2013
  • In this study, the silicone thermal curing degree of the silicone-encapsulated quantum dot light emission diode was measured using the various types of chemical ligands around quantum dot. It was confirmed that the trioctyl phosphin oxide (TOPO) ligand around the quantum dot was responsible for dispersion of the quantum dot in silicone encapsulant and decline of the thermal curing degree of the silicone encapsulant. Also, it was confirmed that the thermal curing degree of silicone encapsulants containing the steric acid (SA) and the dodecanoic acid (DA) ligands were higher than the one of TOPO ligand.

Mechanical and Thermal Properties of Cured Specimen or DGEBA/DDM System (DGEBA/DDM계 에폭시수지 경화 시험편의 기계적 및 열적특성)

  • Kim, Kong-Soo;Park, Jun-Ha;Kim, Ki-Wun;Kim, Young-Jun
    • Elastomers and Composites
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    • v.33 no.1
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    • pp.10-16
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    • 1998
  • In DGEBA/DDM system, the curing specimen are many curing factors which can affect on thermal and mechanical properties. This study was performed to prove the effect on curing specimen prepared by changing of the curing factors which are curing time and temperature of DGEBA/DDM system. As a result on thermal and mechanical properties, flexural strength, modulus and glass transition temperature (Tg) were increased with curing time and temperature were increased. It was found that the optimum curing condition of DGEBA/DDM system cure at $150^{\circ}C$ for 3hrs at equivalent ratio of 1/1.

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Review on Carbonation Curing and Thermal Stability of Calcium Sulfoaluminate Cement (칼슘설포알루미네이트 시멘트의 탄산화 양생과 열 안정성에 관한 검토)

  • Wu, Xuanru;Kunal Krishna, Das;Jang, Jeong Gook
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.53-54
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    • 2023
  • In recent decades, climate change has become an issue of global importance. The calcium sulfoaluminate (CSA) cement emits lower CO2 than the Portland cements while manufacturing. However, ettringite, which is a main hydration product of CSA cement, starts dehydrating at a temperature above 100℃, hence it may limit the CSA cement for high temperature application. Recently, an early carbonation curing of cement-based material has been extensively studied in terms of carbon neutralization. The carbonation curing of CSA cement has a potential to transform the AFt and AFm phases into calcium carbonate, and the transformation of unstable hydrates to stable hydrates can increase the resistance to elevated temperature. This review study summarizes and discusses the carbonation curing effect of CSA cement and the thermal stability of CSA cement exposed to elevated temperatures.

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Hydration Characteristics according to First Curing Condition in Solid Hydrated by Hydro-Thermal Synthesis Reaction (수열합성경화체의 1차 양생조건에 따른 수화특성)

  • Kim, Jin-Man;Jung, Eun-Hye;Park, Sun-Gyu
    • Journal of the Korea Concrete Institute
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    • v.20 no.5
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    • pp.543-548
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    • 2008
  • Solid hydrated by hydro-thermal synthesis reaction is cured two times, the first curing is the steam curing at atmospheric pressure and the second one is a high-pressure steam curing, that is autoclaving. Steam curing is to acquire the proper strength for the resistance of treatment in the first curing process, it was not evaluated properly so far. Because of ignorance about curing, some engineers even think that the dry curing is better than the steam curing. The relation between compressive strength of solid hydrated by hydrothermal synthesis reaction and curing condition are presented in this paper. In order to investigate the effect of curing on the strength properties of specimen, the hydration behavior of solid hydrated by hydro-thermal synthesis reaction has been studied over curing condition using XRD, DT-TGA and porosimeter, SEM analysis technique. The results show that the specimens which are cured with blended method of dry and steam curing appear to have better strength properties than that of dry curing and steam curing. Also, there are significant difference of hydration behavior among curing condition in the solid hydrated by hydro-thermal synthesis reaction.

Effect of Stereoisomeric Structures of Curing Agents on Curing Behaviors, Thermal and Mechanical Properties of Epoxy Resins (경화제의 입체 이성질체 구조가 에폭시 수지의 경화 거동과 열 및 기계적 특성에 미치는 영향)

  • Lee, Minkyu;Kwon, Woong;Jeong, Euigyung
    • Textile Coloration and Finishing
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    • v.30 no.3
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    • pp.180-189
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    • 2018
  • To study the effect of stereoisomeric structures of curing agents on curing behaviors, thermal and mechanical properties of epoxy resins, DGEBA(diglycidyl ether of bisphenol A) epoxy resin and 3,3'- and 4,4'-DDS(diaminodiphenyl sulfone) curing agents were selected. The curing initiation temperature and activation energy of DGEBA/3,3'-DDS was lower than DGEBA/4,4'-DDS. DGEBA/3,3'-DDS has a faster curing rate and higher degree of cure than DGEBA/4,4'-DDS, suggesting that 3,3'-DDS has higher reactivity than 4,4'-DDS. Tensile strength and fracture toughness of DGEBA/3,3'-DDS was lower than those of DGEBA/4,4'-DDS, indicating that mechanical properties of the epoxy resin can be different only by the stereoisomeric difference in chemical structure of the curing agent.