• Title/Summary/Keyword: Hardening Catalyst

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Preparation and Properties of Low-shrinkage Polymer Concretes (저수축형 폴리머 콘크리트의 제조 및 물리.역학적 특성)

  • 황진하;연구석;이윤수;이기원
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.321-326
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    • 2000
  • Many different polymer based concrete materials are known today, but the large setting or hardening shrinkage of polymer concrete is a problem to overcome in their practical applications. The setting shrinkage reaches about five to ren times he drying shrinkage ordinary cement concrete, i.e, 50 to $60\times10^{-4}$. This paper deals with a reduction in the hardening shrinkage of unsaturated polyester resin concrete which is treated with respect to shrinkage-reducing agent content, S/a ratio and catalyst content, and tested for length change during hardening, and flexural and compressive strength. It is show that the change of shrinkage-reducing agent content and S/a ratio affected the length change of the unsaturated polyester resin concrete during hardening.

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A STUDY ON THE POLYMERIZATION STRESS OF COMPOSITE RESINS (복합레진의 중합수축력에 관한 연구)

  • Kim, Boo-Rang;Choi, Ho-Young;Min, Byung-Soon;Park, Sang-Jin;Choi, Gi-Woon
    • Restorative Dentistry and Endodontics
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    • v.17 no.2
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    • pp.331-341
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    • 1992
  • The purpose of this study was to measure the polymerization contraction stress of two types of composite resins; chemical cured type(Cliarfil F II, Kuraray, Japan) and photo-cured type(Photo-Clearfil Bright, Kuraray, Japan). The stresses of composite resin by contraction measured with specially designed measuring device(Fig. 1). The stresses caused by shrinkage during hardening of specimens were measured according to the type of composite resins, thickness of specimen(0.65, 1.30 and 1.95mm), and ratio of catalyst to base in case of only chemical cured composite resin(0.5, 1.0 and 1.5). As the composite resin specimen shrank on hardening, the load cell recorded force vs time automatically on pen-recorder(Toa, Japan) with a cross-head speed 60mm/hr at 0~10 voltages up to 2 hours. The experiments were conducted in a room maintained at $23{\pm}2^{\circ}C$ and relative humidity $50{\pm}10%$. The results were as follows. 1. The contraction stress during hardening was higher in photo cured composite resin than in chemical cured composite resin. 2. The contraction stress during hardening was increased with thickness of composite resin specimen. 3. In chemical cured composite resin, the polymerization contraction stress was decreased with ratio of catalyst and base. 4. The contraction stress during polymerization was higher in early time after insertion of photo cured composite resin and chemical cured composite resin.

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A Study on the Strengths of Polyurethane Morthar Cured under Low Temperature Condition (저온양생한 폴리우레탄 모르타르의 강도특성에 관한 연구)

  • 오종석;정효석;박홍신;조영국;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.337-342
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    • 1999
  • The Purpose of this study is to evaluate the strength characteristics of polyurethane(PUR) mortar cured under low temperature condition. PUR mortars are prepared with various catalyst content, methylene chloride(MC) content as a viscosity reducing agent, and curing age at low temperature condition of $0^{\circ}C$, -5$^{\circ}C$ and -1$0^{\circ}C$, tested for working life, compressive and flexural strengths. From the test results, the catalyst and MC contents affect the degree of hardening and blowing of PUR mortar. Strengths increase with an increasing catalyst content at low temperature. Flexural and compressive strength of PUR mortar are about 177kgf/$\textrm{cm}^2$ and 490kgf/$\textrm{cm}^2$ respectively at curing temperature of -1$0^{\circ}C$ with catalyst content of 0.4%. Therefore, it is apparent that this PUR mortars have a sufficient strengths for repair of concrete structures.

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Study on Low Temperature Curing Emulsion of PLA Fiber for Bedding (침장용 PLA 섬유에 대한 저온 경화유제에 관한 연구)

  • Ahn, Young-Moo
    • Journal of Fashion Business
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    • v.16 no.1
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    • pp.41-51
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    • 2012
  • Polyester is mainly used as a bedding filler material. PLA fiber as an eco-friendly material for substituting polyester has a low melting temperature and therefore a hardening process is impossible. This study is to develop the oil for feather touch that can treat at the melting temperature of PLA. The slippery and soft aminosilicone emulsion, and the bulky epoxysilicone emulsion were used. They had proper viscosity and particle size for flexibility and elasticity. When using methoxy aminosilane [$H_2NSi(OCH_3)_3$] as an aminosilane and [$Zn(OCOCH_3)_2$] as a catalyst, the hardening reaction was fast and effective. Feather touch process were treated by 2 steps. At first step, aminosilicone emulsion, epoxysilicone emulsion and methylaminosilane were mixed and homogenized, and at second step, 5% blened solution of the first step, Zn catalyst 1%, distilled water 94% were treated at PLA fiber. After treatment the static friction coefficient and dynamic friction coefficient were reduced to 23.5-60.8% and 30.0-61.3% respectively, and the laundry and sun light fastnesses have not shown any decrease.

Study on the Development of Super-High-Early-Strength Mortar Using the Hardening catalyst and High early strength cement (조강시멘트를 사용한 초조강 모르타르 개발에 관한 연구)

  • Cho, In-Sung;Hur, Yeon-Ok;Min, Tae-Beom;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.11a
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    • pp.217-219
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    • 2012
  • In this study, the experiment was conducted in the level of mortar as one of the basic studies on pre-cast concrete which acceleration curing is not done. This study has the purpose to develop the strength of mortar into 20MPa within 6 hours in the condition of room temperature using admixtures which can accelerate C3S hydration reaction. In this experiment, W/C was fixed into 20%, PCE which can stimulate C3S was used as an accelerating admixture. From the results of this experiment, maximum content of accelerating admixture was 1%. Also, as more than 20MPa was measured through 6-hour compressive strength, it can be known that strength can be developed without steam-curing.

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Relationships between Exotherm Temperature and Working Life of Lightweight Polyester Mortars (경량 폴리머 모르타르의 발열온도특성과 가사시간의 관계)

  • ;;Katsunori Demura
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.315-318
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    • 1999
  • This paper deals with the relationships between the exotherm temperature and working life of lightweight polyester mortar. Polyester mortars using types of lightweight aggregate compositions are prepared, and tested for exotherm temperature during hardening and working life. It is concluded from the test results that the behavior of exotherm temperature of lightweight polyester mortars is considerably affected by the lightweight aggregate composition. The lightweight polyester mortars using a lightweight aggregate compositeion ES gradually develop an exotherm temperature from 2$0^{\circ}C$, and give a working life. Then the exotherm temperature rises sharply up to a maximum exotherm temperature. The working life of the lightweight polyester mortars shortens with increasing catalyst and accelerator contents. The maximum exotherm temperature of the lightweight polyester mortars rises with increasing catalyst and accelerator contents.

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Peroxidase를 이용한 cardol의 중합과 경화 거동

  • Park, Seung-Yeong;Kim, Yong-Hwan;Ryu, Jeong-Yong;Song, Bong-Geun
    • 한국생물공학회:학술대회논문집
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    • 2003.04a
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    • pp.121-125
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    • 2003
  • Enzymatic polymerization of cardol derived from cashew nut shell liquid have been examined. t-Butyl alcohol aqueous systems showed high yield of polycardol when SBP was as biocatalyst. Compared other solvents, peroxidase actiyity was maintained stable, which was seemed major cause. Solvent aqueous system and concentration of hydrogen peroxide were found to have an influence on the yield and molecular weight distribution of polycardol under the reaction of enzymatic polymerization using peroxidase. The polymer was subjected to the hardening by methyl ethyl ketone peroxide and cobalt naphthenate catalyst, giving a crosslinked tough film. Polycardol was cured rapidly and the hardness increased with time. Finally, the pencil scratch hardness reached to 7H, which is enough hard for industrial uses.

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Study on the Application of Domestic Artificial Sands for the Self-hardening Molding Process by Using Furan Resin (후란자경성(自硬性) 주형용(鑄型用) 국산인조규사(國産人造硅砂)의 활용(活用)에 관(關)한 연구(硏究))

  • Choi, Chang-Ock;Lee, Sang-Yun
    • Journal of Korea Foundry Society
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    • v.1 no.3
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    • pp.19-29
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    • 1981
  • An emphasis has been placed on the importance of selecting a sand for furan sand process, which ie affected by the properties of sand. Investigations have been carried out to use the domestic artificial sands for the furan sand process. For laboratory investigations, the sands have been prepared and tested for chemical analysis, loss on ignition, sieve analysis, AFS grain fineness number, grain shape, PH value, acid demand, surface shape, theoretical surface area, moisture absorption, crushing durability and compressive strength and S. S. I. of molding sands. Most commercial sands have been found to be able to be used. The main requirement of the sands has been shown to be that 3 or 4 screen sands, AFS no.40-70 (or 100), of low acid demand, good surface area and good grain shape require less resin and catalyst to give an adequate strength.

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A Fundamental study on the Characteristics of Zeolite Cement Mortar (제올라이트 시멘트 모르타르의 재료적 특성에 관한 기초 연구)

  • Jo, Byung-Wan;Kang, Suk-Won;Park, Seung-Kook;Choi, Ji-Sun
    • Journal of the Korea Concrete Institute
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    • v.23 no.2
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    • pp.203-209
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    • 2011
  • The cement industry is expected to face a major set-back in the near future due to its large energy consumption and $CO_2$ production, causing global warming. In order to overcome these environmental problems, this research has bee carried out to find a cement substitute material. One possible cement substitute material is Zeolite cement. In this study, the materialistic characteristics of Zeolite cement mortar were evaluated. Natural Zeolite cement mortar was prepared using alkali activation (NaOH) instead of water ($H_2O$) to determine achievable strength and appropriate mixing ratio. Based on the mixing ratio, functional material was added to alkali active agent to harden Zeolite mortar to develop a highly functional construction material. The study result showed that pure Zeolite cement mortar achieved compressive strength of 42 MPa in 7 days depending on the mixing amount of alkaline catalyst and the hardening temperature, showing high efficiency and possibility as a new construction material.

The Effect of Additives on Sound Absorption Coefficient of Polyurethane Foam (폴리우레탄폼의 흡음율에 대한 첨가제의 영향)

  • Park, Nam-Cook;Kim, Young-Chul;Park, Chong-Rai
    • Applied Chemistry for Engineering
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    • v.8 no.2
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    • pp.197-203
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    • 1997
  • The effect of additives on the mechanical properties of polyurethane foam were investigated. The resin used in this study was prepared by adding catalyst, surfactant and cross-linker to both KONIX FA-703 polyether polyol(80%) and KONIX FA-733 polyether polyol(20%). The polyurethane was foamed by adding equivalent amount of isocyanate(TDI-80, prepolymer M-200, pure MDI) to the resin and was used in property measurements after 72 hours hardening. The physical properties of polyurethane foam were investigated in terms of density, tensile strength, tear strength, elongation, sound absorption coefficient and gel profile measurements. The effects of surfactant on the cell size was investigated by scanning electron microscopy(SEM). The sound absorption coefficient was directly related to the cell size. The physical properties were improved with increasing amount of surfactant(L-5309) until 1.0 part per hundred polyol(1.0pphp).

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