• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 춘계학술논문 발표대회
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• pp.59-62
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• 2007

Nowadays, polymer-cement mortars are widely used in construction field(floorings and pavements, water-proofings, adhesives, repair materials, deck coverings, anti-corrosive linings) Because of excellent performance such as high tensile and flexural strength, waterproofness, excellent adhesion, good durability, improved wear and chemical resistances. This article presents the results of experimental study that investigates the effect of ambient temperature on the strength properties of polymer-modified cement mortar. Results show that when increasing the polymer proportion in mortar on different ambient temperature, the compressive strength and flexural strength are decreased, and also alkali resistance is decreased.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.125-128
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• 2005

The dispersion of carbon nanofiber (CNF) was carried out by solution blending, mechanical mixing, and sonication. CNFs at levels of 5-50% fiber weight content were mixed with polypropylene (PP) powder, and then were melt-mixed using a twin-screw extruder. For the further alignment of fibers, extruded rods were stacked uni-directionally in the mold cavity for the compression molding. For the evaluation of mechanical properties of nanocomposites, tension, in-plane shear, and flexural tests were conducted. CNF/PP composites clearly showed reinforcing effect in the longitudinal direction. The tensile modulus and strength have improved by 100% and 40%, respectively for 50 % fiber weight content, and the flexural modulus and strength have increased by 120% and 25%, respectively for the same fiber weight content. The shear modulus showed 65% increase, but the strength dropped sharply by 40%. However, the property enhancement was not significant due to the poor adhesion between fiber and matrix. In the transverse direction, the tensile, flexural, and shear strength decreased as more fibers were added.

• 한국산학기술학회논문지
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• 제10권6호
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• pp.1298-1303
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• 2009

현무암 단섬유로 강화시킨 시멘트 복합재료의 섬유장과 혼입률에 따른 인장강도와 굽힘강도의 변화를 고찰하였다. 인장 및 굽힘강도의 증가는 섬유장의 증가에 따른 효과보다는 섬유 혼입률의 증가가 더 큰 역할을 하였다. 또한 현무암 단섬유와 시멘트 사이의 우수한 계면 접착력은 물리적 성질의 향상에 좋은 영향을 미친다고 보여진다. 시멘트의 수화시 생성되는 알칼리 조건과 유사한 포화 $Ca(OH)_2$ 용액에서의 중량감소율을 관찰한 결과 현무암 단섬유는 3주 동안의 침지 후에도 매우 작은 중량감소율을 나타냈다.

• 한국염색가공학회지
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• 제34권3호
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• pp.157-164
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• 2022

This study tried to analyze the heat resistance properties by blending epoxy and phenolic resin in a certain ratio, and to analyze the adhesive properties at the time of metal-polymer hetero-adhesion by applying Epoxy-phenolic resin between a silicon steel sheet and m-aramid sheet, the viscosity, adhesive peel strength, and adhesive cross section were measured using a rotational rheometer, a tensile tester(UTM), and a field emission scanning electron microscopy(FE-SEM). The thermal stability and heat resistance were confirmed by measuring the mass loss according to the temperature increase using Thermogravimetric analysis(TGA). After blending with epoxy and Phenolic resin(1:0.25 ratio) curing at 110℃ for 10 min, high adhesive strength was improved more than 40% compared to the adhesive strength using epoxy alone. When the space between the silicon steel sheet and m-aramid sheet, which is created during curing of the E-P blend, is cured with a slight weight, it is possible to control the empty space and improve adhesion.

• 구강회복응용과학지
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• 제16권2호
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• pp.161-170
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• 2000

The use of autopolymerizing-cured resin and light-cured resin for direct relining of complete and partial dentures has been popular. This investigation compared the adhesion of autopolymerizing-cured reline resin(Tokuso Rebase, Mild Rebaron) or light-cured reline resin(Mild Rebaron LC, Lighton-U) to metal base or resin base. Cylindrical samples were made from metal($Biosil^{(R)}$) or heat-cured resin(QC-20) and were prepared to produce a flat bonding surface. Cylindrical metal samples were roughened by scratch or by scratch and sandblast and were treated with primer(MR Bond) after scratch and sandblast. And then, liners were prossesed to the cylindrical metal or resin samples according to the manufacturer's recomendations so as to bond metal base or resin base. The specimens were tested in pure tension by using an Instron Univasal testing machine for the four direct reline resins. The results were as follows ; 1. In comparison with tensile bond strength of material relined on resin base or metal base, the case of resin base produced significantly higher tensile bond strengths than the case of metal base. 2. Metal surface pretreatment or primer improved the tensile bond strength between the reline resin and the metal($Biosil^{(R)}$) base. 3. The tensile bond strengths of Mild Rebaron LC relined on resin base or metal base were similar to those of the other reline resins.

• 한국세라믹학회지
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• 제44권9호
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• pp.496-501
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• 2007

The properties of the polymer-modified mortars are influenced by the polymer film, cement hydrates and the combined structure between the organic and inorganic phases. Also, this quality of polymer modified cement strongly depend on weather condition. To overcome this problem, polymer-modified cement based on rapid setting cement mortars were prepared by varying polymer/cement mass ratio (P/C) with a constant water/cement mass ratio of 0.5. The effect of polymer on the hydration of this polymer cement is studied on different curing temperature. The results showed that the polymer mortar which is modified with rapid setting cement have superior physical strength properties on independent curing temperature. In addition the PIC ratio, the compressive strength, flexural strength, tensile strength and adhesion strength of mortar is enhances and polymer-modified cement based on rapid setting cement is more beneficial to the improvement of the mortar properties in jobsite.

• 접착 및 계면
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• 제13권3호
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• pp.121-130
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• 2012

본 연구에서는 대나무섬유의 분쇄 유 무에 따라 섬유함량이 각각 30, 40, 50 wt%인 대나무/PLA 펠렛을 압출공정으로 제조하고 사출공정을 통해 대나무/PLA 바이오복합재료를 성형하여 그들의 기계적, 열적, 충격 특성과 수분흡수성을 조사하였다. 대나무/PLA 바이오복합재료의 굴곡탄성률, 인장탄성률, 저장탄성률 및 충격강도는 neat PLA에 비하여 두드러지게 증가되었다. 특히 탄성률은 분쇄된 대나무섬유의 도입에 의하여 더욱 증가하였다. 또한 분쇄한 대나무섬유의 사용이 바이오복합재료의 장시간 동안 측정한 수분에 대한 저항성 증가에 효과적이었다. 대나무섬유의 사용이 neat PLA의 열변형온도를 약 16% 향상시키는 효과를 나타내었으나, 분쇄된 대나무섬유의 사용에 의한 증가는 미미하였다. 분쇄된 대나무섬유의 사용은 바이오복합재료의 인장강도와 충격강도에는 크게 영향을 주지 않았다.

• Elastomers and Composites
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• 제34권3호
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• pp.229-238
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• 1999

본 연구에서는 제3의 성분으로 벤젠 술폰산계열 반응성 화합물과 ENB 및 DCPD를 사용하여 비diene계 고분자인 EVA를 특수 화학적 처리에 의하여 EVA의 주쇄에 불포화기 즉, 이중결합을 도입시켰다. 또한 이중결합도입 EVA와 diene계 범용합성고무인 CR, SBR과의 블렌드를 통하여 황가 황체를 제조하여 가황체들의 물리적 특성을 비교 검토하였다. 검토결과 원래의 EVA가 갖고 있는 green strength, 사출 압출 성형성, 접착성, 점착성, 치수안정성, 오존저항성 등의 장점은 그대로 살리면서도 황가황이 가능하여 열가소성의 EVA가 갖는 사용온도의 한계 문제와 기계적 특성 즉, 경도, 인장강도, 인장 응력, 신장율 등온 향상시켰다. 비diene계 고분자와 diene계 고분자의 블렌드에 있어서 개질에 대한 연구가 더 수행되어진다면 합성고무에서 나타나는 부족한 가공성, 내산화 안정성, 접착성 등을 크게 향상시킬 수 있을 것이며 아울러 EVA의 융해유동성을 이용한 고무제품 가공공정의 연속화가 가능하게 될 것이다.

• Advanced Composite Materials
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• 제16권4호
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• pp.335-347
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• 2007

Green composites composed of long maize fibers and poly $\varepsilon$-caprolactone (PCL) biodegradable polyester matrix were manufactured by the thermo-mechanical processing termed as 'Sequential Molding and Forming Process' that was developed previously by the authors' research group. A variety of processing parameters such as fiber area fraction, molding temperature and forming pressure were systematically controlled and their influence on the tensile properties was investigated. It was revealed that both tensile strength and elastic modulus of the composites increase steadily depending on the increase in fiber area fraction, suggesting a general conformity to the rule of mixtures (ROM), particularly up to 55% fiber area fraction. The improvement in tensile properties was found to be closely related to the good interfacial adhesion between the fiber and polymer matrix, and was observed to be more pronounced under the optimum processing condition of $130^{\circ}C$ molding temperature and 10 MPa forming pressure. However, processing out of the optimum condition results in a deterioration in properties, mostly fiber and/or matrix degradation together with their interfacial defect as a consequence of the thermal or mechanical damages. On the basis of microstructural observation, the cause of strength degradation and its countermeasure to provide a feasible composite design are discussed in relation to the optimized process conditions.

• 접착 및 계면
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• 제18권4호
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• pp.159-165
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• 2017

본 연구에서는 반응성 희석제로 사용되는 BA의 함량에 따른 자외선 경화형 폴리우레탄 아크릴레이트 수지를 제조하여 수지의 열적 기계적 성질, 접착강도, 굴곡성을 확인하였다. BA의 함량이 40% 이상으로 증가할수록 Polyol의 Tg와 아크릴 수지의 Tg가 분리되어 나타난 것을 DSC로 통해 확인하였다. 또한 BA의 함량이 증가할수록 아크릴 수지의 낮은 기계적인 물성이 주도적으로 발현되어 인장강도와 신장률, 접착강도가 감소하는 것으로 나타났다. 굴곡성을 평가한 결과 BA의 함량이 40%인 경우 경도가 낮으면서 다른 수지에 비해 Tm이 낮아 굴곡성이 우수한 것으로 나타났다.