• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.483-496
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• 1993

Dentin hypersensitivity medicaments such as Gluma, Scotchbond 2, All-Bond 2, which are resin adhesives, were used to compare the sealing effects of dentinal tubule under mechanical stress. Topical application of above medicaments on the dentin surfaces of extracted teeth followed by artificial tooth brushing for 6 weeks was performed for the comparison. The following conclusions on the degree of dentinal tubule exposure versus time by were reached by using polyvinyl siloxane impression material for taking the impression, epoxy resin for the duplication and SEM for observing the surface. 1. SEM was used to compare the accuracy of the duplicated surface, but no differences were found when teeth samples and the duplicated surfaces were observed. 2. After comparing the degree of dentinal tubules exposure with varnish applied contrast group, resin adhesive materials showed much less exposure as time went by. 3. The results indicated that AU-Bond 2 adhesive, under mechanical stress, showed lesser exposure of dentinal tubules comparing with Gluma and Scotchbond 2 adhesives After the results were put together, it was demonstrated that resin replica method is an useful way to evaluate the treatment effects of the dentinal tubule hypersensitivity medicaments. Also, it was noticed that under mechanical stress, All-Bond 2, classified as fourth generation, illustrated the best dentinal tubules sealing effects.

• Structural Engineering and Mechanics
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• 제87권4호
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• pp.375-389
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• 2023

In many fiber concrete beams with Carbon Fiber Reinforced Polymer (CFRP), debonding occurs between the carbon sheets and the concrete due to the low strength of the bonding resin. A total of 42 fiber concrete beams with a cross-section of 10×10 cm with a span length of 50 cm are fabricated and retrofitted with CFRP and subjected to a 4-point bending test. Graphene Oxide (GO) at 1, 2, and 3 wt% of the resin is used to improve the mechanical properties of the bonding resins, and the effect of length, width, and the number of layers of CFRP and resin material are investigated. The crack pattern, failure mode, and stress-strain curve are analyzed and compared in each case. The results showed that adding GO to polyamine resin could improve the bonding between the resin and the fiber concrete beam. Furthermore, the optimum amount of nanomaterials is equal to 2% by the weight of the resin. Using 2% nanomaterials showed that by increasing the length, width, and number of layers, the bearing and stiffness of fiber concrete beams increased significantly.

• 접착 및 계면
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• 제23권4호
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• pp.101-107
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• 2022

Adhesive joints have many advantages such as weight savings, corrosion and fatigue resistance and now developed even withstand of high impact and dynamic loads. However, an adhesion has cumbersome and complicated surface preparation processes. The surface preparation step is critical in adhesive joint manufacturing in order to obtain the prescribed strength for adhesive joints. In this study, it was attempted to simplify and reduce the number of surface preparation steps, and abrasion and rapid adhesive application (ARAA) process is developed for an alternative solution. The abrasion processes are performed only for creating surface roughness in standard procedures (SP), although the abrasion processes cause surface activation itself. The results showed that there is no need the long procedures in laboratory or chemical agents for adhesion. After the abrasion process, the attracted and highly reactive fresh surface layer obtained, and its effect on bonding success is observed and analyzed in this research, in light of the essential physic and adhesion theories. Al 6061 aluminum adherends and epoxy-based adhesives were chosen for bonding processes, which is mostly used in light vehicle parts. The adherends were cleaned, treated and activated only with abrasion, and after the adhesive application the specimens were tested under quasi-static loading. The satisfied ARAA results were compared with that of the specimens fabricated by the standard procedure (SP) of adhesion processes of high impact loads.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1313-1314
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• 2013

• 접착 및 계면
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• 제5권2호
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• pp.1-7
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• 2004

A novel carboxyl terminated butadiene-acrylonitrile (CTBN) modified, low temperature cure epoxy film adhesive was developed in this paper. It can be cured at as low as $75^{\circ}C$ for 4 hours with a pressure of 0.1MPa. After post cure at $120^{\circ}C$ for 2 hours, the bonding strengths of Phosphoric Acid Anodizing(PAA) surface treated aluminum adherend were similar to those of structural film adhesives curing at $120^{\circ}C$. It is suitable to bond both metal/composite laminate-to-laminate and laminate to honeycomb structure.

• 마이크로전자및패키징학회지
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• 제28권2호
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• pp.89-94
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• 2021

최근 플렉시블 기기의 상용화를 위하여 기계적 신뢰성 연구가 활발히 진행되고 있으며 이를 고려하여 신뢰성 높은 다양한 접합부의 구현이 중요하다. 기기의 많은 부피를 차지하는 고분자 기판 또는 필름을 접합할 때에는 재료의 약한 내열성으로 접합공정 중 열 손상이 발생할 수 있으므로 신뢰성을 확보를 위해 상온 접합공정이 필요하다는 제약이 있다. 기존의 기판 접합을 위해 사용되는 에폭시 또한 고온 경화가 요구되는 경우가 많고, 특히 경화 접합 후 에폭시는 접합부 유연성 및 피로 내구성에서 한계를 보인다. 이를 해결하기 위하여 접착제 사용이 없는 저온 접합 공정의 개발이 필요한 상황이다. 본 연구에서는 마이크로파에 의한 탄소나노튜브 가열을 이용한 고분자 기판의 저온 접합공정을 개발하였다. PET 고분자 기판에 다중벽 탄소나노튜브 (MWNT)를 박막 코팅한 뒤 이를 마이크로파로 국부 가열함으로써 접합 기판 전체는 저온을 유지하며 CNT-PET 기계적 얽힘을 유도하는 방식이다. PET/CNT/PET 접합시편에 600 Watt 출력의 마이크로파를 10초간 조사함으로써 유연기판 접합에 성공하였고 매우 얇은 CNT 접합부를 구현하였다. 접합 시편의 기계적 신뢰성을 평가하기 위해 중첩 전단 강도 시험, 삼점 굽힘 시험, 반복 굽힘 시험을 수행하였으며 각 시험으로부터 우수한 접합강도, 유연성, 굽힘 내구성이 확인되었다.

• 마이크로전자및패키징학회지
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• 제22권1호
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• pp.35-41
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• 2015

In this study, in order to improve the reliability of ACF interconnections, solder ACF joints were investigated interms of solder joint morphology and solder wetting areas, and evaluated the electrical properties of Flex-on-Board (FOB) interconncections. Solder ACF joints with the ultrasonic bonding method showed excellent solder wetting by broken solder oxide layers on solder surfaces compared with solder joints with remaining solder oxide layer bonded by the conventional thermo-compression (TC) bonding method. When higher target temperature was used, Sn58Bi solder joints showed concave shape due to lower degree of cure of resin at solder MP by higher heating rate. ACFs with epoxy resins and SAC305 solders showed lower degree of resin cure at solder MP due to the slow curing rate resulting in concave shaped solder joints. In terms of solder wetting area, solder ACFs with $25-32{\mu}m$ diameters and 30-40 wt% showed highest wetted solder areas. Solder ACF joints with the concave shape and the highest wetting area showed lower contact resistances and higher reliability in PCT results than conventional ACF joints. These results indicate that solder morphologies and wetting areas of solder ACF joints can be controlled by adjustment of bonding conditions and material properties of solder and polymer resin to improve reliability of ACF joints.

• Restorative Dentistry and Endodontics
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• 제28권3호
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• pp.203-208
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• 2003

The purpose of this study was to evaluate the effect of salivary contamination of teeth on bonding efficacy of self-priming and self-etching DBSs. The materials used were Single Bond(SB, self-priming system, 3M), Unifil Bond(UB, self-etching system, GC), and Scotchbond Multi-Purpose Plus(SM, 3M) as control. Forty five human molars randomly allocated to three groups as dentin bonding systems tested and embedded in epoxy resin. Then the specimens were wet-ground to expose flat buccal enamel surface or flat occlusal dentin surface and cut bucco-lingually to form two halves with slow speed diamond saw. One of them was used under non-contamination, other under contamination with saliva. The bonding procedure was according to the manufacturer's directions and resin composite(Z-100, 3M Dental Products, St. Paul, MN) was built-up on the bonded surface 5mm high. The specimens were ground carefully at the enamel-composite interface with fine finishing round diamond bur to create an hour-glass shape yielding bonded surface areas of $1.5{\pm}0.1\textrm{mm}^2$. The specimens were bonded to the modified microtensile testing apparatus with cyanoacrylate, attached to the universal testing machine and stressed in tension at a CHS of 1mm/min. The tensile force at failure was recorded and converted to a tensile stress(MPa). Mean values and standard deviations of the bond strength are listed in table. One-way ANOVA was used to determine significant difference at the 95% level. The bond strength of SBMP and SB were not affected by salivary contamination, but that of UB was significantly affected by salivary contamination. These results indicate that DBSs with total etch technique seems less likely affected by salivary contamination in bonding procedure.

• ETRI Journal
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• 제46권2호
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• pp.347-359
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• 2024

A simultaneous transfer and bonding (SITRAB) process using areal laser irradiation is introduced for high-yield and cost-effective production of mini- or micro-light-emitting diode (LED) display panels. SITRAB materials are special epoxy-based solvent-free pastes. Three types of pot life are studied to obtain a convenient SITRAB process: Room temperature pot life (RPL), stage pot life (SPL), and laser pot life (LPL). In this study, the RPL was found to be 1.2 times the starting viscosity at 25℃, and the SPL was defined as the time the solder can be wetted by the SITRAB paste at given stage temperatures of 80℃, 90℃, and 100℃. The LPL, on the other hand, was referred to as the number of areal laser irradiations for the tiling process for red, green, and blue LEDs at the given stage temperatures. The process windows of SPL and LPL were identified based on their critical time and conversion requirements for good solder wetting. The measured RPL and SPL at the stage temperature of 80℃ were 6 days and 8 h, respectively, and the LPL was more than six at these stage temperatures.

• 콘크리트학회논문집
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• 제27권1호
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• pp.29-35
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• 2015

최근 연구되고 있는 해상 초대형 부유 콘크리트 구조물의 제작은 현장 타설이 어렵다는 단점이 있으므로 프리캐스트 콘크리트로 제작한 모듈을 수상에서 인양 후 프리스트레스력으로 접합 및 제작하는 것을 목표로 한다. 그러나 해상 환경에서 발생하는 다양한 하중 및 예상되는 상부 구조물에 의한 하중을 고려하였을 때, 프리스트레스력으로 접합되는 콘크리트 모듈 간의 접합부의 안정적인 거동 및 성능이 요구된다. 이에 프리스트레스력이 적용되기 전 가접합에 수중용 에폭시를 이용한 접합 방법이 고려되고 있는데, 수중용 에폭시는 고점성의 재료로서 내부에 공극이 발생하기 쉽다. 이를 해결하기 위하여 마이크로 실리카를 혼입하여 공극을 감소시킨 수중용 에폭시를 이용하여 콘크리트 부유체의 접하 거동에 대한 평가가 요구된다. 그러므로 이번 연구에서는 마이크로 실리카를 혼입한 수중용 에폭시를 이용하여 가접합하고 프리스트레싱을 적용한 시험체를 제작하여 성능을 평가하였다. 마이크로 실리카를 혼입한 수중용 에폭시로 접합된 콘크리트 모듈은 프리스트레싱만을 적용한 시험체에 비하여 균열 발생 및 응력 집중 현상이 완화되었으며, 최대 하중 및 변위는 일체형 RC 시험체에 비하여 10% 미만의 감소율을 나타내어 모듈형 콘크리트 부유체의 수상 접합을 위한 안정적인 접합재료로 사용 가능할 것으로 보인다.