• 한국염색가공학회지
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• 제30권3호
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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.

• Advances in concrete construction
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• 제9권1호
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• pp.33-41
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• 2020

In this study, polyethylene glycol (PEG) and polyacrylamide (PAM) have been used as self-curing agents to produce self-curing concrete (SC). Compressive strength, ultrasonic pulse velocity (UPV), bulk electrical resistivity, chloride ion penetrability, water permeability, and main microstructural characteristics were examined under different curing regimes, and compared to those of the control concrete mixture with no self-curing agents. One batch of a control mixture and one batch of a SC mixture were air-cured in the lab to act as non-water-cured samples. The water curing regimes for the control mixture included continuous water curing for 3, 7, and 28 days and periodical moist curing using wetted burlap for 3 and 7 days. Curing regimes for the SC mixtures included 3 days of water curing and periodical moist curing for 3 and 7 days. SC mixtures showed better microstructure development and durability performance than those of the air-cured control mixture. A short water curing period of 3 days significantly improved the performance of the SC mixtures similar to that of the control mixture that was water cured for 28 days. SC concrete represents a step towards sustainable construction due to its lower water demand needed for curing and hence can preserve the limited water resources in many parts of the world.

• 폴리머
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• 제24권2호
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• pp.201-210
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• 2000

에폭시 수지의 삼차원 망목상 구조 형성에 관한 근본적이고 화학구조에 바탕을 둔 미세구조 및 물성 발현에 대한 연구의 일환으로, 말단 관능기가 같은 아민 경화제의 주쇄에 포함된 질소 및 탄소원자의 개수가 반응특성, 열적 특성, 그리고 기계적 특성에 미치는 영향을 조사하였다. 열적 특성을 측정하기 위하여 DSC, TGA, TMA 분석을, 기계적 특성 및 파단특성 분석을 위하여 인장 시험, 삼점 굴곡시험, 광학현미경 분석을 행하였다. 그 결과, 주쇄의 사슬길이가 짧을수록 반응열이 크고 최대 발열온도와 열안정성이 낮아졌다. 또한 최대 반응전환율은 주쇄의 사슬길이가 길어질수록 증가하였다. 경화물의 경우 밀도는 주쇄의 사슬길이와는 큰 관계가 없으나, 인장탄성율은 주쇄의 사슬길이가 짧을수록 크고, 인장강도는 그와 반대의 경향을 보인다. 그 외의 shrinkage, 유리전이온도, 굴곡탄성율, 굴곡강도는 주쇄의 사슬길이와는 일견 무관한 불규칙한 형태를 보였다. 이는 최대 반응전환율의 차이가 이러한 특성에 큰 영향을 미치는 것을 나타낸다. 굴곡 파단특성은 최대 반응전환율과 밀접한 관계를 나타내었다.

• Composites Research
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• 제17권6호
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• pp.44-51
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• 2004

에폭시 경화계에서 말단 관능기가 같은 선형아민 경화제의 주쇄에 포함된 에틸기에 결합된 질소원자 개수가 반응특성 및 열적, 기계적특성에 미치는 영향을 알아보기 위하여, 빈용 에폭시수지인 DCEBF (diglycidyl ether of bisphenol F)를 DETA (diethylenetriamine), TETA (triethylenetetraamine) 그리고 TEPA (tetraethylenepentaamine)와 1:1 당량비로 경화하였다. 이 연구에서 DGEBF/아민계에서 경화제 주쇄의 질소원자 거수에 의하여 반응특성 및 열적성질, 기계적특성에 중대하게 영향을 미쳤다. 즉, 주쇄의 질소원자 개수가 작을수록 반응열이 많고 최대발열온도가 낮아졌다. 경화물의 경우 밀도와 최대반응전환률은 주쇄의 질소원자 개수와는 큰 관계가 없으나, 굴곡탄성률과 인장탄성률은 주쇄의 질소원자 개수가 작을 수록 크다. 그 외의 열안정성, 부피수축률(%), 유리전이온도, 인장강도, 굴곡강도는 주쇄의 질소원자 개수와는 일견 무관한 불규칙한 경향을 보인다. 이는 최대반응전환률(%)의 차이가 이러한 특성에 영향을 미치는 것을 나타낸다.

• 한국염색가공학회지
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• 제10권4호
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• pp.1-6
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• 1998

It is important in the durable water and oil repellent finishing for wool fabric what kinds of water-repellent agents will be used. Water repellent agents and its concentration were aleady chosen in the previous paper, one of the crosslinking agents which has less damages(harsh handle or yellowing) to the treated fabrics was a low molecular weight urethane-based resins(eg. Elastron BN-11). In repellent finishing, fabrics were padded in a bath which contained aqueous solution of water-repellent agents, and crosslinking agents, and wetting agents, followed by drying and curing. The most suitable treating condition for excellent repellency and durability to dry-cleaning was as follows ： Fabrics are padded at liquor pick-up ratio of 50%, with aqueous solution which contained $30g/\ell$ of water-repellent agents, and $1g/\ell$ of crosslinking agents, and 40g/s of wetting agents. And the padded fabrics were dried at $110^\circ{C}$ for 1 minute, and cured at $160^\circ{C}$ for 1 minute. For the fabrics, water and oil repellencies and durability to repeated dry-cleanings were observed. For enhancing the durability to dry-cleaning, the role of crosslinking agents was important for they bonds water-repellent agents and fibers to 3-dimensional net structure. Therefore, the most suitable drying and curing conditions should be selected according to the kinds of crosslinking agents.

• Elastomers and Composites
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• 제55권2호
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• pp.95-102
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• 2020

Currently, peroxide cure is a widely used cure system for rubber materials. To improve its effectivity, co-agents are used to enhance the peroxide efficiency and mechanical properties of rubber materials. Co-agents are multifunctional organic compounds that are highly reactive towards free radicals. These co-agents provide higher cross-link densities for a given peroxide concentration and improve the mechanical properties of peroxide-cured rubber composites. In this study, trimethylolpropane trimethacrylate (TMPTMA) and high vinyl 1,2-polybutadiene (HVPBD) were used as co-agents. In order to obtain a concentration that achieves a favorable balance between mechanical properties and co-agent concentration, this research investigated the effects of co-agent content on the curing characteristics, chemical structures, and mechanical properties of HNBR composites. Additionally, the heat aging properties and compression sets of HNBR composites were investigated. Based on the results, we found that the HNBR composites with TMPTMA co-agents exhibited higher Shore A hardness and 10% modulus and better heat aging resistance and compression set than that of the HVPBD co-agent. The heat aging resistance and compression set deteriorated with increasing HVPBD content.

• 한국해양공학회지
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• 제18권4호
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• pp.46-51
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• 2004

The surface layer in dredged and reclaimed marine clay is improved by mixing of shallow soils and hardening agents, which is made of cement, containing some other special admixtures. Tests in both laboratory and field settings are performed to investigate the improvement effect and strength properties of cement-stabilized soils. The test results show that the hardening agent sufficiently improves the soil properties of the surface layer, while increasing the load-carrying capacity. The strength of cement-stabilized soils depends, primarily, on water-to-cement ratio and curing temperature. That is, the higher curing temperature and the longer curing time, the higher the strength in cement-stabilized soils. The high ratio of water-ta-cement results in a lower strength.

• 접착 및 계면
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• 제12권2호
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• pp.67-72
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• 2011

Acrylic pressure-sensitive adhesives are used in many different parts in the world. But acrylic acid in PSAs may occur unexpected results such as corroding adherends or producing by-products when applied within electronic devices. This study employed acrylic PSAs based on 2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA) and butyl acrylate (BA) with different coating thickness. There are two types of curing agents. One is methylaziridine derivative (MAZ) and the other is aluminum acetylacetonate (AlACA). This study examined the adhesion performance and curing behaviors using peel strength, probe tack and gel fraction. Also, the viscoelastic properties of acrylic PSAs were investigated from Advanced rheometric expansion system (ARES).

• 한국인쇄학회지
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• 제30권2호
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• pp.59-68
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• 2012

As one of the eletronic device industries has been developed by using a recent printing method, the consumption of Ag paste has been on the rise as well. The printing method has simple processes in comparison with other methods. Also it enables to be large-scaled and to lower price ranges. If UV curing system would be applied to the printing method, energy consumption and dangerousness from curing system can be minimized in a short period of time so that its method can be more eco-friendly. This study conducted an experiment in order to make UV curing Ag paste which is feasible to implement micro patterns with different dispersing agents. The purpose of the study is to analysis the suitable printability for micro pattern and to test dispersibility, hardening properties, conductivity and adhesive stength by measuring viscosity, TI(thixotropy index), G', G", $tan{\delta}$(G"/G') after making paste. We have experimented with four dispersing agents. After We did an analysis of characteristic of rheology, conductivity and adhesive stength, etc, We confirmed that the paste added FP 3060 has excellent dispersibility, conductivity and adhesive stength. If the paste has excellent dispersibility, we will expect that micro pattern is made by that.

• Journal of Nutrition and Health
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• 제47권6호
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• pp.484-488
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• 2014

Purpose: This study investigated the question of whether the addition of natural ingredients (pear fermented solution, celery powder, vitamin C) in curing agents may influence antioxidant activities and nutritional characteristics of smoked duck. Methods: Smoked duck samples with general or natural curing agent containing three additive ingredients were examined to determine total polyphenol contents, antioxidant activities, pH, TBARS, and food additives residue (nitrite ion, antioxidant, sodium glutamate). Results: Smoked duck with natural curing agent showed a higher level of total polyphenol content and antioxidant activities than smoked duck using general curing agent (p < 0.05). The pH and TBARS of smoked duck were significantly decreased by the addition of natural curing ingredients compared to those of smoked duck using general curing agent (p < 0.05). The residues of food additives were not detected in smoked duck using natural curing agent. Conclusion: Findings suggest that the addition of pear fermented solution, celery powder, and vitamin C in natural duck curing agent may improve the antioxidant activities and nutritional characteristics of smoked duck and provides health benefits.