• Elastomers and Composites
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• v.34 no.1
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• pp.31-44
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• 1999

Interfacial adhesive strength between the fully-crosslinked and partially-crosslinked rubber layers were Investigated at the temperature range of $30{\sim}120^{\circ}C$ for four different rubbers(NR, SBR, EPDM, BIMS). The surfaces of interfacial failure were also investigated using a scanning electron microscopy(SEM). The physical interlinking played a major role in the adhesive strength between the fully-crosslinked rubber layers. When a partially-crosslinked rubber layer was bonded to the fully-crosslinked one, the chemical as well as the physical interlinking affected the adhesive strength. NR showed a "interfacial knotty tearing" pattern, while EPDM showed a typical "cross-hatched" one when the adhesive strength approached to the cohesive tear strength of each material.

• Proceedings of the Korean Fiber Society Conference
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• 1997.04a
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• pp.26-31
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• 1997

유리섬유/nylon 6 복합재료의 계면결합강도를 증가시키기 위하여 r-APS(r-Aminopropyltriethoxysilane)로 유리섬유의 표면을 처리 하였다. 이때 표면처리의 최적 조건을 찾기위해서 처리후 기기분석과 계면결합강도 측정 등을 하였다. 농도, pH, 처리시간, 온도를 변화시키면서 표면처리를 한 후 흡착량을 살펴본 결과 처리 농도에 의해서는 흡착량이 단조증가하였으며 처리시간에 따라서는 5분정도에서, 처리온도에 의해서는 30C 부근에서 최대 흡착량을 보였다. 또한 pH에 따른 흡착량은 silane의 고유 pH인 10.5부근에서 최대치를 나타냈다. FR-IR 분석에 의하면 NH2의 NH3 bending mode가 1607cm-1, 1575cm-1에서 나타났으며 SiOH의 SiO band는 960cm-1에서 나타났다. XPS를 통해서는 N ls와 Si 2p의 존재를 확인할 수 있었다. 표면처리된 유리섬유와 matrix인 nylon 6를 이용해 단섬유내장시편을 만들어 fragmentation test를 한 결과 계면결합강도는 약 5분의 처리시간과 1%(wt%)의 농도에서 최대값을 보였다.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.625-642
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• 2000

The purpose of this study is to evaluate the effects of mechanical and thermal fatigue stress on the shear, tensile and shear-tensile combined bond strengths(SBS, TBS, CBS) in various orthodontic brackets bonded to human premolars with chemically cured adhesive(Ortho-one, Bisco, USA). Five types of commercially available metal brackets with various bracket base configurations of Photoetched base(Tomy, Japan), Non-Etched Foil Mesh base(Dentaurum, Germany), Micro-Etched Foil Mesh base(Ortho Organizers, USA), Chessboard base(Daesung, Korea), and Integral base(3M Unitek, USA) were used. Samples were divided into 3 groups, the first group was acted with shear-tensile combined loads($45^{\circ}$) of 200g for 4 weeks(mechanical fatigue stress), the second group was subjected to the 5,000 thermocycles of 15 second dwell time each in $5^{\circ}C\;and\;55^{\circ}C$ baths(thermal fatigue stress), and the third group was the control. Bond strengths were measured at the crosshead speed of 0.5mm/min. The cross-section of bracket base/adhesive interface and the fracture surface were examined with the stereoscope and the scanning electron microscope. The resin remnant on bracket base surface was assessed by ART(Adhesive Remnant Index). The obtained results were summarized as follows, 1. In static bond strength, Photoetched base bracket showed the maximum bond strength and Integral base bracket showed the minimum bond strength(p<0.05). In all brackets, shear bond strength(SBS) was in the greatest value and shear-tensile combined strength(CBS) was in the least value(p<0.05). 2. After mechanical fatigue test, Photoetched base bracket showed the maximum bond strength and Integral base bracket showed the minimum bond strength(p<0.05). In Photoetched base bracket and Micro-Etched Foil Mesh base bracket, shear bond strength(SBS), tensile bond strength(TBS) and shear-tensile combined strength(CBS) were decreased after mechanical fatigue test(p

• Journal of Adhesion and Interface
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• v.5 no.1
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• pp.21-28
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• 2004

In this work, glass fiber/nylon 6 and woven glass fiber/nylon 6 composites have been fabricated using glass fiber reinforcements sized with 3-chloropropyltrimethoxysilane(CTMS) having a chloropropyl organo-functional group in the molecular chain end. The interfacial shear strength of glass fiber/nylon 6 composite was measured using a single fiber microbonding test and the interlaminar shear strength and the storage modulus of woven glass fabric/nylon 6 composites were measured using a short-warn shear test and a dynamic mechanical analysis, respectively, informing the effect of the concentration of CTMS on the properties. With increasing CTMS concentration, the interfacial properties of the composites were improved. The results on the interfacial shear strength, interlaminar shear strength, interlaminar failure pattern, and storage modulus with varying the CTMS concentration agree with each other.

• Journal of the Korean Vacuum Society
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• v.2 no.3
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• pp.374-383
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• 1993

필라멘트와 Si 기판 사이의 기전력을 20, 80, 140, 200V로 증가시키면서 EACVD에 의하여 성장된 다이아몬드 박막에 대하여 다이아몬드/Si 계면분석 및 계면강도를 측정하였다. 주사형전자현미경(SEM), 고분해능투과형전자현미경(HRTEM), 오제이전자분석기(AES)에 의해 계면상태를 분석한 결과, 기전력 증가에 따라 활성탄화수소 이온(CmHn-)에너지가 증가되어져 CmHn-이 Siso로 침투(Impringement)가 증가되고 침투된 높은 에너지의 CmHn-이 Si과 화학결합하여 생성되는 SiC층 깊이 및 농도 분포도 증가된다. 풀 시험(Pull test)에 의한 계면강도 측정 결과, SiC층 깊이 및 농도분포가 증가할수록 계면강도가 증가하였다. 관찰된 파면과 파면의 X-선 메핑 결과 및 HRTEM과 AES에 의한 분석 결과, 기전력 증가에 따라 공극율이 적고 치밀한 다이아몬드 박막이 성장된다. 그리고 생성되는 SiC층 농도 및 깊이 분포가 증가함에 따라 다이아몬드/Si 계면이 강화되고, 상대적으로 파괴는 다이아몬드/Si 계면이 아닌 SiC층이나 Si 내부에서 발생된다. 결국, 기전력을 증가하여 활성탄화수소이온의 에너지를 증가함으로써 계면강도가 우수하며 공극율이 매우 적고 치밀한 다이아몬드 박막을 성장할 수 있다.

• Restorative Dentistry and Endodontics
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• v.29 no.1
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• pp.1-12
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• 2004

이 연구는 발거 소구치에서 5급 와동을 형성하여 접착 시스템 및 와동 위치에 따른 상아질에 대한 접착시스템의 미세 인장결합강도의 차이를 비교, 연구하였다. 접착방법은 resin-modified glass ionomer(Gl), compomer(부식여부에 따라 DE 및 DN군으로 분류), 그리고 상아질 접착제인 Single Bond(SB) 및 Cleayfil SE Bond(SE)와 복합레진(Clearfil AP-X)을 사용한 5개의 실험군으로 분류하였다. 소구치 협측 치경부에 wedge형태의 와동을 형성하고 5종의 접착 시스템을 제조자의 지시에 따라 적용, 충전하여 시편을 제작하여 미세인장결합강도를 측정하고, One-way ANOVA / Duncan's test로 통계분석하였다. SEM 검사는 미세인장결합강도의 시편제작과 동일한 방법으로 시편을 제작한 후 관찰하였다. 실험 결과, 상아질 접착제 및 복합레진(SB, SE)의 미세인장결합강도가 GI보다 높게 나타났고(p<0.05), 치은측이 교합측보다 더 낮게 나타났으며, CI, DE, SE에서 유의성 있게 낮게 나타났다(p<0.05). Compomer에서 conditioning 여부(DN, DE)에 따른 변화는 치은측에서만 유의차 있는 것으로 나타났다. SEM 관찰에서, 교합측의 상아세관은 결합 계면과 평행하게 주행하였고, 치은측에서는 결합계면에 수직으로 주행하는 것으로 관찰되었다.

• Composites Research
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• v.31 no.6
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• pp.299-303
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• 2018

In order to improve the interfacial bonding force and reaction polymerization degree of the carbon fiber reinforced nylon 6 composite material, the surface of the existing epoxy-sizing carbon fiber was desized to remove the epoxy and treated with urethane, nylon and phenoxy sizing agent, was observed. The interfacial bond strength of the resized carbon fiber was confirmed by IFSS (Interfacial Shear Strength) and the fracture surface was observed by scanning electron microscope. The results showed that the interfacial bonding strength of the carbon fiber treated with nylon and phenoxy sizing agents was higher than that of urethane - based sizing. It has been found that the urethane - type resizing carbon fiber has lower interfacial bonding strength than the conventional epoxy - sizing carbon fiber. This result shows that the interfacial bonding between carbon fiber and nylon 6 is improved by removing low activity and smoothness of existing carbon fiber.

• Composites Research
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• v.19 no.4
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• pp.15-22
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• 2006

One of the primary factors limiting the application of composite-metal adhesively bonded joints in structural design is the lack of a good evaluation tool for the interfacial strength to predict the load bearing capacity of boned joints. In this paper composite-steel adhesion strength is evaluated in terms of stress intensity factor and fracture toughness of the interface corner. The load bearing capacity of double lap joints, fabricated by co-cured bonding of composite-steel adherends has been determined using fracture mechanical analysis. Bi-material interface comer stress singularity and its order are presented. Finally stress intensities and fracture toughness of the wedge shape bi-material interface corner are determined. Double lap joint failure locus and its mixed mode crack propagation criterion on $K_1-K_{11}$ plane have been developed by tension tests with different bond lengths.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.298-307
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• 2010

The purpose of this study was to assess the effect on oxygen inhibition layer(OIL) for the interfacial bonding between resin composite layers, including shear bond strength, fracture modes and degree of conversion. The first layer of specimen was filled with Z-250(shade A3) and was cured for 40s. The second layer of specimen was filled with same composite(shade A1) and was cured for 40s. The first layer of specimens for each group were prepared by methods as followings. Control(curing in atmospheric air), Group1(curing against Mylar strip), Group2(scrubbed with a acetone-soaked cotton), Group3(using Tescera light cup), Group4(using Tescera heat cup), Group5(stored in disti1led water for 30days at $37^{\circ}C$), Group6 (using bonding agent). The results were as follows: 1. There was no statistically significant different shear bond strength between control and group 1(p>0.05). 2. Group 2 showed significantly lower shear bond strength than control and group 1(p<0.05). 3. The observation of the fracture surface leads to the evidence that a major difference occurs in the case of control, group1 and group 3 samples which break mainly cohesively while the other groups break in majority adhesively. 4. The results of FTIR showed that the degree of conversion was the highest in group 2 and the lowest in control group(p<0.05). It can be concluded that an OIL is not necessary for bonding with composite resin. But if a reduced critical amount of the unreacted monomer is present, it was detrimental to bonding additional layers of composite. Further study, such as the quantitative analysis of the unreacted monomer are required.

• Journal of Korea Foundry Society
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• v.41 no.6
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• pp.535-542
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• 2021

In this study, to improve the interfacial bond strength of cast iron-aluminum dissimilar materials, graphite was removed to a certain depth from the cast iron surface through de-graphitization heat treatment. As the heat treatment time increased, the depth at which graphite was removed increased, showing a linear relationship between the heat treatment time and depth. Aluminum was filled to a certain depth on the de-graphitized cast iron surface through die-casting method, and no intermetallic compounds were formed on the cast iron-aluminum interface. The interfacial bonding strength showed a value of 90 MPa regardless of the heat treatment time, which is very high compared to the 12MPa bonding strength of the material without de-graphitization heat treatment. This result is thought to be due to the mechanical bonding of the undercut structure as the liquid aluminum, penetrated by the high pressure die-casting process, solidified in the de-graphitized region of the cast iron.