• 접착 및 계면
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• 제17권2호
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• pp.67-71
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• 2016

본 연구에서는 반응성 희석제 함량에 따라 접착강도 및 물성을 향상시키기 위해 polyether polyol/polyester polyol, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), 2-butanone oxime (MEKO)를 사용하여 저점도 폴리우레탄 핫멜트를 합성하였다. 합성된 저점도 폴리우레탄 핫멜트의 물성은 FT-IR, viscosity meter 및 UTM 등을 통해 확인하였다. 반응성 희석제의 함량이 증가하고 NCO-blocked prepolymer가 감소함에 따라 저점도 폴리우레탄 핫멜트 접착제의 점도는 증가하였으며, OH-terminated oligomer, NCO-blocked prepolymer, 반응성 희석제 함량의 비가 1 : 0.5 : 0.5일 때 1.1 kgf/cm 접착강도를 나타내었다.

• 공업화학
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• 제16권6호
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• pp.827-833
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• 2005

본 연구에서는 폴리아미드계 수지를 이용하여 최적의 핫멜트 접착제 배합설계를 접착제 합성, 물성평가 및 철에 대한 접착력 평가를 통해 구축하고자 하였다. 최적 배합설계를 위해 앞선 연구결과에 따라 CM831과 843P의 기본 수지에 점착부여수지로 테르펜수지의 무게비를 각각 75/25/10으로 고정한 후 왁스, 충전제 등이 사용되었으며 이들의 종류와 첨가량이 접착제의 흐름 특성과 접착력에 미치는 영향을 조사하였다. 결과에 따르면 왁스의 경우 폴리에틸렌 왁스의 첨가량이 증가함에 따라 용융점도는 다소 감소하였지만 철과의 최적 접착력은 5 wt%에서 나타났다. 이는 접착제 자체의 기계적 물성과 밀접한 관계가 있음을 알 수 있었다. 충전제의 경우는 탈크가 10 wt% 첨가되었을 때 다소 높은 용융점도에 비해 우수한 접착성능을 나타내었다.

• 대한토목학회논문집
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• 제39권4호
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• pp.523-530
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• 2019

포트홀 발생 및 관련 교통사고 건수는 매년 꾸준히 증가하는 추세이며 이에 따른 인명피해, 차량파손에 따른 비용손실 등 도로 이용자의 직 간접적인 피해를 증가시키고 있다. 일반적으로 아스팔트 혼합물은 생산과정부터 시공 후 공용에 따라 지속적으로 노화가 진행된다. 포장 노화는 균열과 수분침투로 박리를 야기하고 반복적인 윤하중에 의해 포장구조를 약화시켜 포트홀을 유발하게 된다. 본 연구에서는 노화가 아스팔트 콘크리트 포장에 미치는 영향을 검토하기 위해 노화정도에 따른 부착성능 평가와 수분민감성 평가를 수행하였다. 연구결과 노화에 따라 아스팔트 바인더의 점성이 증가해 부착강도가 2~3배 이상 증가하였다. 또한 가속 노화시킨 아스팔트 혼합물의 경우 간접인장강도의 증가뿐만 아니라 TSR 값도 4.2~8.9 % 증가하는 것으로 나타났다. 이에 따라 골재에 아스팔트 바인더가 피복된 상태에서 노화가 진행될 경우 아스팔트 바인더와 골재의 부착력이 증가하여 박리 저항성이 향상되는 것으로 분석되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.148-149
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• 2020

Currently, the most commonly used EPS insulation material has been mainly used because its ease of adhesion with concrete. However, due to poor adhesion with wallpaper, separate adhesion needs to be strengthened and there are cases of breakage or grooves in the process of dismantling the mold. The biggest problem is that when a fire breaks out, various harmful substances are present and highly flammable. Cork used in this study is a truly eco-friendly building material that is taken from between the outer and inner bark of cork trees and does not damage the wood. Also, it is a porous material that is made up of countless cells and contains an air gap between the cells. It is very light in weight between 0.06 and 0.07 and has excellent insulation with a heat conductivity of 0.04W/mK. In addition, it has high stability in the topic of conversation because it does not produce harmful gas when burned and has self-sustaining properties. However, research on cork, an eco-friendly building material with excellent performance to date, is scarce Therefore, we encourage existing scholars to raise interest in new eco-friendly building materials through this study. It also aims to manufacture insulation boards with new inorganic properties using the low weight and heat conductivity held by the cork.

• 한국응용과학기술학회지
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• 제28권1호
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• pp.35-47
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• 2011

For the synthesis of water soluble acrylic modified epoxyester resin, fatty acid/epoxy ratio of 50/50 was used, and introduced maleic anhydride. Ratio of styrene/acrylic acid of acrylic monomers was fixed 85/15 and ratio of epoxyester/acrylic monomer was controlled 80/20, 75/25, 70/30, 65/35, and degree of neutralization were changed 65%, 80%, to 100%. As a result, 40% solids acrylic modified epoxyester resins were synthesized. Resins were evaluated water soluble stability, drying time, water resistant, storage stability and physical properties. And the white paints were prepared, and were evaluated viscosity, drying time, water resistance, adhesion, sagging, spray workability, gloss, salt spray resistance, skinning, whiteness and flash rust. As a result, the degree of neutralization of 100% and the ratio of epoxyester/acrylic monomer of 75/25 showed the best properties.

• The Korean Journal of Ceramics
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• 제2권1호
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• pp.43-47
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• 1996

$RuO_2$ thin films deposited directly on Si substrate by RF magnetron sputtering method using $RuO_2$ target have been investigated. Special interest was focused on the effect of process parameter on the surface roughness of $RuO_2$ films. Crystallization behavior and electrical properties of the films deposited at $300^{\circ}C$ were superior to those deposited at room temperature. Metallic Ru phase was formed in pure Ar and this phase had resulted poor adhesion after post annealing process in oxidizing ambient. Microstructural analysis reveals that the size of the $RuO_2$ crystallites gets smaller and the surface becomes smoother as the $O_2$ partial pressure or film thickness decreases. Irrespective of the $O_2/Ar$ ratio, resistivity of $RuO_2$ films ranged in $50~70 {\mu}{\Omega}-cm$. As the film thickness decreases, there is a thickness where the resistivity rises abruptly. Such an onset thickness turned out to be dependent n the $O_2$/Ar ratio.

• 한국재료학회지
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• 제30권5호
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• pp.223-230
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• 2020

As a case study on aspect ratio behavior, Kaolin, zeolite, TiO₂, pozzolan and diatomaceous earth minerals are investigated using wet milling with 0.3 mm media. The grinding process using small media of 0.3 pai is suitable for current work processing applications. Primary particles with average particle size distribution D₅₀, ~6 ㎛ are shifted to submicron size, D₅₀ ~0.6 ㎛ after grinding. Grinding of particles is characterized by various size parameters such as sphericity as geometric shape, equivalent diameter, and average particle size distribution. Herein, we systematically provide an overview of factors affecting the primary particle size reduction. Energy consumption for grinding is determined using classical grinding laws, including Rittinger's and Kick's laws. Submicron size is obtained at maximum frictional shear stress. Alterations in properties of wettability, heat resistance, thermal conductivity, and adhesion increase with increasing particle surface area. In the comparison of the aspect ratio of the submicron powder, the air heat conductivity and the total heat release amount increase 68 % and 2 times, respectively.

• Journal of the Korean Wood Science and Technology
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• 제49권2호
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• pp.169-180
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• 2021

Inherent crystalline domains present in low formaldehyde to urea (F/U) molar ratio urea-formaldehyde (UF) resins are responsible for their poor adhesion in wood-based composite panels. To modify the crystallinity of low molar ratio (LMR) UF resins, this study investigates the additional effect of cellulose nanomaterials (CNMs), such as cellulose microfibrils (CMFs), cellulose nanofibrils (CNFs), and TEMPO-oxidized CNFs (TEMPO-CNFs) on the crystallinity of modified LMR UF resins. First, two modification methods (post-mixing and in situ) were compared for modified LMR UF resins with TEMPO-CNFs. The modified UF resins with TEMPO-CNFs decreased the nonvolatile solid contents, while increasing the viscosity and gel time. However, the in situ modification of UF resins with TEMPO-CNFs showed lower crystallinity than that of post-mixing. Then, the in situ method was compared for all CNMs to modify LMR UF resins. The modified UF resins with CMFs using the in situ method increased nonvolatile solid contents and viscosity but decreased the gel time. The crystallinity of UF resins modified with TEMPO-CNFs was the lowest even though the crystalline domains were not significantly changed for all modified UF resins. These results suggest that these CNMs should be modified to prevent the formation of crystalline domains in LMR UF resins.

• 접착 및 계면
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• 제13권3호
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• pp.116-120
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• 2012

본 연구에서는 수분산 폴리우레탄의 내가수분해성을 개선하기 위하여 polyester polyol, $H_{12}MDI$, DMPA 및 sulfopropylated polypropyleneglycol-${\alpha}$,${\omega}$-diamine (SP)을 사용하여 수분산 폴리우레탄을 합성하였다. 유리전이온도는 SP 함량의 증가에 따라 증가하다가 NCO/OH 비가 1.8에서는 감소하였다. 또한 SP의 함량이 증가함에 따라 인장강도와 내가수분해성은 증가하는 경향을 나타내었으며, SP로 사슬연장한 WPU-SP에서 인장강도 감소율은 약 WPU-SP-1을 제외한 나머지에서 약 2~5%정도로 내가수분해성이 향상되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.1005-1010
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• 2001

Recently, polymer-modified mortar has been studied for proposed use on industrial floors as top layers with thin thicknesses, typically 5~ 15mm. The purpose of this study is to evaluate basic properties of self leveling materials using polymer modifier as kinds of SBR, PAE, SUBA. Superplasticizer and thickener have been included in the mixes to reduce bleeding and drying shrinkage as well as in order to facilitate the workability required. The self leveling materials using four types of polymer dispersion are prepared with polymer-cement ratios which respectively range from 50%, 75%, and were tested for basic characteristics such as adhesion in tension, crack resistance test, rebound test after the preparative tests for unit weight, air content, consistency ratio etc. The results show almost as equal quality as existing commercial industrial flooring when mortar is modified by polymer dispersion. Adhesion in tension of polymer modified mortars using each SBR and PAE emulsion was over 10 kgf/$cm^{2}$. Crack or flaw derived from shrinkage is strongly dependent on the type of polymer dispersion because of each different total solid of polymer. It is judged that polymer modified mortar with self-leveling can be very well suited for Floor-finished.