• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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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.

• Restorative Dentistry and Endodontics
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• 제17권2호
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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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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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.

• 패션비즈니스
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• 제16권1호
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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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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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.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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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.

• 한국주조공학회지
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• 제1권3호
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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.

• 콘크리트학회논문집
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• 제23권2호
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• pp.203-209
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• 2011

시멘트 산업은 에너지 다소비형이며 석회석을 원료로 하고 있어 지구 온난화의 주범인 CO를 배출하여, 환경문제로 인해 가까운 시기에 큰 어려움을 겪을 것으로 예상되고 있다. 오늘날 첨단산업의 발전과 지구환경 문제의 심각성에 대한 인식이 증가하여 시멘트 산업에서도 다각화 측면에서 다양한 종류의 기술 등이 활성화되고 있는 시점이다. 이 연구에서는 최근에 새로이 검토되고 있는 시멘트 대체 재료로서 천연 제올라이트를 주원료로 사용한 제올라이트 시멘트 모르타르에 관한 재료적 특성을 분석하는데 목적이 있으며 그 방법으로 물($H_2O$)대신 알칼리 활성제(NaOH)를 사용하여 알칼리 경화반응을 이용한 제올라이트 모르타르를 제조하여, 강도 특성 및 적정 배합비를 구하였다. 그 결과 알칼리 활성제의 양과 경화 온도에 따른 천연 제올라이트 시멘트 모르타르의 7일 압축강도가 42 MPa로 측정되는 등 기존 시멘트보다 뛰어난 성능을 나타내는 것으로 판단되어지며, 기존 건설용 재료를 대체할 가능성이 충분히 있다고 사료된다.

• 공업화학
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• 제8권2호
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• pp.197-203
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• 1997

본 연구에서는 폴리우레탄폼 제조시 사용되는 첨가제가 폴리우레탄폼의 기계적 물성에 미치는 영향에 대하여 조사하였다. 실험에 사용된 수지는 KONIX FA-703 폴리에테르폴리올(80%)과, KONIX FA-733 폴리에테르폴리올(20%)에 촉매, 계면활성제, 가교제 등을 혼합하여 제조하였으며, 이 수지에 이소시아네이트(TDI-80, prepolymer M-200, pure MDI)를 당량비로 첨가하여 발포시킨 폼을 상온에서 72시간 경화시킨 후 물성측정에 사용하였다. 폴리우레탄폼의 기계적 물성은 밀도, 인장강도, 인열강도, 신장율, 흡음율 및 gel profile을 조사함으로써 측정하였고, 셀 크기에 대한 계면활성제의 영향은 주사전자현미경(SEM)을 사용하여 측정하였다. 흡음율은 셀의 크기와 직접적인 관련이 있었으며, 계면활성제(L-5309)의 사용량에 따른 인장강도, 인열강도 및 흡음율 등 기계적 물성은 1.0pphp 까지는 첨가량이 많아질수록 증가하는 경향을 보이다가 점차 감소하였다.