• Title/Summary/Keyword: Curing effect

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Curing of Epoxy Resins by Aminophosphazene Derivatives and Its Thermal Properties (아미노포스파젠 유도체에 의한 에폭시수지의 경화와 열적성질)

  • 윤흥수
    • Textile Coloration and Finishing
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    • v.11 no.6
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    • pp.7-17
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    • 1999
  • Aminophosphazene derivatives were prepared from hexachlorocyclotriphosphazene and used for the curing agents of epoxy resins. The effect of the curing agent on the dynamic viscoelastic properties, flame proofing, and heat resistance of the cured epoxy resins were investigated and compared with those for the epoxy resins cured with aliphatic and aromatic amines. The epoxy resin cured by 1,1-diamino-3,3,5,5-tetrachlorocyclotriphosphazene showed the highest storage modulus and glass transition temperature when cured at 19$0^{\circ}C$ for 6 hours. The epoxy resins cured with phosphazene derivatives showed superior flame proofing to those with aliphatic amine and aromatic amine. Particularly it is an effective curing agent for epoxy resins to enhance the storage modulus, flame proofing and resistance to heat.

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Effect on the Properties of Coated Paper by Drying Temperature and Curing Time (건조 온도 및 경화시간이 도공지 품질에 미치는 영향)

  • 박동국;최희연;김영하;이용규
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.34 no.4
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    • pp.16-21
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    • 2002
  • It was observed that drying temperature and curing time in the paper coating process as well as Tg of the latex used as a binder, greatly affected the properties of the coated paper such as roughness, paper and print gloss, K & N ink drop, and ink set-off. The higher drying temperature induced faster water evaporation and change in binding density, which caused an increase in paper roughness, ink gloss and ink set-off, but decrease in paper gloss and K & N ink drop. The increased curing time promoted latex filming and redistribution of the binder in coating layer. This increased pick strength and ink gloss, but decreased ink trapping. Finally, the higher Tg of the latex showed the wider changing range of these properties.

Effect of Stem Drying Method during Curing Process on Physico-chemical Properties in Bulk Cured Leaves (Bulk건조에서 주맥건조방법이 잎담배 이화학성에 미치는 영향)

  • 이철환;이병철;진정의
    • Journal of the Korean Society of Tobacco Science
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    • v.22 no.2
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    • pp.133-137
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    • 2000
  • The bulk curing experiment to improve the quality of flue-cured leaves were carried out to evaluate relationship between the modified(3 step-up) drying and conventional drying method in bulk curing process. Modified drying method was somewhat higher values in yellowing color index of cured leaves, and less brittle than those in conventional drying program. As to the chemical properties, there was no difference in chemical component levels in cured leaves between the modified and the conventional methods, while the major chemical compounds in relation to aromatic essential oil of cured leaves showed mostly higher level in the modified method than that in conventional drying method. Additionally 3 step-up drying method increased the tobacco quality by 2 % in price per kg compared with conventional drying method.

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Strength Characteristics of Stabilized Dredged soil and Correlation with Index Properties

  • Kim, Yun-Tae;Do, Thanh-Hai;Kang, Hyo-Shup
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.489-494
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    • 2010
  • A geo-composite soil (GCS) is a stabilized mixture of bottom ash, cement and dredged soil. Various samples with different mass ratios of mixtures were tested under curing time of 7 and 28 days to investigate physical properties and compressive strength. This paper focused on the effect of bottom ash on the strength characteristics of Busan marine dredged soil. Cement has been added as an additive constituent to enhance self-hardening of the blended mixture. The unconfined compressive strength of GCS increases with an increase in curing time due to pozzolanic reaction of the bottom ash. The strength after 28 days of curing is found to be approximately 1.3 to 2.0 times the strength after 7 days of curing, regardless of mixture conditions. The secant modulus of GCS is in the range of 55 to 134 times the unconfined compressive strength. The correlation of unconfined compressive strength with bottom ash content and initial void ratio are suggested.

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Strength recovery of fire-damaged concrete after post-fire-curing (화재 후 재양생 조건에 따른 콘크리트의 강도복원특성)

  • Lee, Joong-Won;Choi, Kwang-Ho;Hong, Kap-Pyo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.170-173
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    • 2006
  • The purpose of this study is to investigate the effect of post-fire-curing on the strength recovery of fire-damaged concrete The 170 specimens have been tested with variables of concrete strengths(20, 30, 40, 50, 60Mpa) exposed to elevated temperatures till $600^{\circ}C$ and $800^{\circ}C$. After natural cooling, the specimens were subjected to post-fire-curing in water and in a controlled chamber for a total duration of 56days. Unstressed compressive strength was conducted to examine the change in the concrete. The test results indicated that the post-fire-curing results in substantial strength recovery and its extent depend on the method and duration of recuring.

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PULP RFSPONSE TO SELF-CURING RESIN (즉시중합(卽時重合) 레진에 대(對)한 치수반응(齒髓反應))

  • Lim, Sung-Sam
    • Restorative Dentistry and Endodontics
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    • v.2 no.1
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    • pp.7-9
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    • 1976
  • This study was performed to reveal the effect of self-curing acrylic resin to dental pulp when the resin was used directly on the freshly cut dentin. Class V cavity preparations were made on the teeth of dogs with No. 701 carbide bur at a speed of 200,000 rpm and with an air water spray. Petrolatum jelly was coated on the inner surfaces of the cavities. After that, doughs of self-curing acrylic resin were filled in these cavities and before completely set these were removed and cemented with zinc oxide and eugenol cement. The dogs were sacrified between 1 day and 3 weeks at the intervals of one week and routinely processed with hematoxylin and eosin stain for histopathologic interpretation. The results were as followings; 1. The inflammatory changes of the pulp can be seen after the use of self-curing acrylic resin on freshly cut dentin. 2. The inflammatory changes of the pulp were not completely subsided until the end of third experimental week.

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Preparation and Properties of Crosslinkable Waterborne Polyurethanes Containing Aminoplast -Effect of Curing Condition-

  • Kwon Ji-Yun;Rahman Mohammad Mizanur;Kim Han-Do
    • Fibers and Polymers
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    • v.7 no.2
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    • pp.95-104
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    • 2006
  • In order to improve the water swelling, thermal/mechanical and adhesion properties of waterborne polyurethane (WBPU), a series of the crosslinkable WBPUs containing hydrophilic ionic component, dimethylol propionic acid (20 mole%), were prepared by in-situ polymerization using a cross-linker hexakis (methoxymethyl) melamine (HMMM). Effects of the HMMM content (2, 4, and 6 wt%) and curing temperature on these properties of the crosslinked WBPUs samples were investigated. All properties were found to increase with increasing HMMM content. It was found that the optimum curing temperature of the WBPU films and adhesives was near $120^{\circ}C$, which was not dependent on the HMMM content.

Fundamental Study on Compressive Strength Recovery for Excessive High-volume Blast Furnace Slag Mortar (고로슬래그가 다량치환된 모르타르의 알칼리 처리에 의한 압축강도 회복 가능성 분석)

  • Choi, Yoon-Ho;Sin, Se-Jun;Lee, Young-Jun;Hyun, Seung-Yong;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.05a
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    • pp.103-104
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    • 2019
  • The aim of the research is assessing the possibility of recovering the compressive strength of the mortar mixture replaced excessively high volume of blast furnace slag accidently. As a result of the experiment, in the case of compressive strength, painting sodium oxide showed higher compressive strength recovery effect than painting calcium oxide. As a curing temperature, 20℃ showed advanced result rather than 65℃. From the wet curing, the reaction was confirmed, deeper penetration depth was checked at 20℃ than 60℃ temperature. Therefore for the concrete mixture with excessively high volume of blast furnace slag, it is considered that painting sodium hydroxide and curing 20℃ can recover the compressive strength effectively.

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Effect of HTPB Binder on Propellant (HTPB 바인더가 추진제에 미치는 영향)

  • Kim, Jeongeun;Ryu, Taeha;Hong, Myungpyo;Lee, Hyoungjin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.504-507
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    • 2017
  • The polybutadiene-based HTPB used as the propellant main binder influences the curing reaction rate of the binder and propellant depending on the synthetic batch. The properties of HTPB synthesized in different batches were analyzed and applied to propellants to evaluate the curing reaction rate and mechanical properties. Finally this reaction can also affect mechanical properties of propellant. And the results suggest that proper degree of curing reaction is necessary to obtain better mechanical properties of propellant.

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Effect of curing temperature on microstructure of blast furnace slag concrete (양생온도가 고로슬래그 콘크리트의 미세구조에 미치는 영향)

  • Lee, Kyu-Dong;Lee, Chang-Soo;Seol, Jin-Seong;Jun, Myeong-Il
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.817-820
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    • 2006
  • This study investigated on the differentiation of microstructure of blast furnace slag concrete(BBSC) using Mercury Intrusion Porosimetry(MIP). From the test result, it was found that the BBSC did not show shortcomings of high temperature curing. The BBSC gives more fineness microstructure than that of plain concrete when it is cured same curing condition. The curing age making stable structure to poor surroundings was 28, 14, 7 days for blast furnace concrete cured at 5, 20, $30^{\circ}C$, respectively.

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