• Journal of dental hygiene science
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• v.9 no.4
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• pp.405-412
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• 2009

The purpose of this study investigated the effect of Au coating on adhesion between porcelain matrix and metal substructure interface. Titanium, Ni-Cr alloy and Co-Cr alloy are well known as proper metal for the dental restorations. The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. However, adhesion between dental alloys and porcelain is related to diffusion of oxygen during ceramic firing. The excessive oxidized layers make hard adhesion between dental alloy and ceramic. Ni-Cr and Co-Cr specimens were divided into test and a control group and Titanium specimens were divided into three test groups and a control group. Each group had 20 specimens. The adhesion characteristics of porcelain and metal with Au coating layer and without Au coating layer were observed with scanning electron microscopy(SEM). The adhesion was evaluated by a biaxial flexure test and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that Au coating layer is effective barrier to diffuse oxide layer completely protect non-precious alloys from oxidation during the porcelain firing. The SEM photomicrographs of cross-section specimens showed a smooth interface between Au coating layer and metals and porcelain which suggested proper chemical bonding, and no gap, porosity were observed. The mode of failure was mainly adhesive for Ti tested specimens, but mixed failures with adhesive and cohesive were observed in Ni-Cr and Co-Cr specimens. The adhesion between non-precious metals and porcelain would not be improved by Au coating agent. However, It is suggested that the continuous study is required further investigation and development.

• Journal of Adhesion and Interface
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• v.17 no.2
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• pp.49-55
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• 2016

In this study, we designed an environment friendly, water-based adhesive using the acrylic emulsion method as a replacement for solvent-based adhesives, which are most commonly used in layered laminates for flexible food packaging. We designed adhesives with different combinations of anionic, non-ionic, and phosphoric ester surfactants, and with different concentrations of chain transfer agent (CTA). We also examined the effect of the degree of cross-linking by synthesizing and comparing 8 test group adhesives with different types of functional monomers. Additionally, we synthesized 2 other test group pressure-sensitive adhesives (PSA) using styrene/alpha-methyl styrene/acrylic acid (SAA) semipolymer dispersing agents (with molecular weights of 13,000 g/mol and 8,600 g/mol, respectively) to replace the conventional surfactants. We evaluated whether the 10 test group pressure-sensitive adhesives met the basic physical property criteria required for flexible food packaging by carrying out a physical analysis of their glass transition temperature (Tg), particle size, adhesion, and molecular weight. In our test, 2 test group adhesives manufactured with the combination of anionic and non-ionic surfactants, CTA concentration of 0.2%, and functional monomers of hydroxyethyl acrylate (HEA) and glycidyl methacrylate (GMA) demonstrated molecular weight and flexibility suitable for flexible packaging, with low adhesiveness and small particle size.

• Journal of Adhesion and Interface
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• v.19 no.2
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• pp.60-67
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• 2018

In the present study, when the surface of kenaf, which is an environmentally friendly natural fiber, was treated by using adhesive solution containing Chemlok 402, the effects of fiber surface treatment, fiber content and fiber length on the cure characteristics, hardness, tensile modulus and abrasion resistance of kenaf/natural rubber composites were investigated. The kenaf fiber contents consisting of the composites were varied with 0, 5, 10, 15, and 29 phr at a fixed fiber length of 2 mm and also the fiber length was varied with 2, 35, and 70 mm at a fixed fiber content of 5 phr. The Tmax and tc90 values, Shore A hardness, tensile modulus, and abrasion resistance of natural rubber composites strongly depended on the kenaf fiber content and length. The characteristics of the composite with kenaf fibers treated with the adhesive solution containing Chemlok 402 were higher than those untreated. This is ascribed to the improved interfacial adhesion between the treated kenaf fiber and the rubber matrix. This study suggests that an appropriate use of adhesive solution may be possible to increase the properties of natural fiber-reinforced composites.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.230-236
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• 2020

In this study, an adhesive tape with water and impact resistance for mobile devices was developed using a UV-curable urethane acrylate based polymer as a substrate. The substrate fabricated by UV-curable materials shows hydrophobicity and poor wettability, which significantly deteriorates the interface-adhesions between the substrate and acrylic adhesive. In order to improve the interface adhesion, 3-glycidoxy-propyl trimethoxysilane (GPTMS), a silane coupling agent having epoxy functional groups, was selected and incorporated into UV-curable urethane acrylate based polymer resins in various contents. The changes of the chemical composition according to the contents of GPTMS was studied with Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) to know the surface bonding properties. Also mechanical properties of the substrate were characterized by tensile strength, gel fraction and water contact angle measurements. The peel strengths at 180° and 90° were measured to compare the adhesion between the substrate and adhesive according to the silane coupling agent contents. The mechanical strength of the urethane acrylate adhesive tape decreased as the silane coupling agent increased, but the adhesion between the substrate and adhesives increased remarkably at an appropriate content of 0.5~1 wt%.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.632-635
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• 2004

In this paper, material property of fiber reinforced concrete(FRC) according to the steel fiber, glass fiber and carbon fiber blended ratio. The fiber reinforced concretes are increased mechanical strength, because the fibers are dispersed with randomly direction and disturb crack progression in concretes. Adhesive fracture is occurred slowly at interface between fiber and concrete, and the fracture energy is absorbed due to softening phenomenon.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.853-858
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• 2003

A new method is proposed to obtain bond-slip model for an adhesive joint between FRP and concrete. Interface element, which can describe the bond behavior, is developed in order to overcome the restriction that complex constitutive relations cannot be modeled in analytic solution. Calibrating numerical bond-slip model to experimental results, multi-objective optimization problem is constructed by physical programming method, and is solved using genetic algorithm. The validity of proposed method is demonstrated by comparing known analytic solution and numerically optimized solution.

• Journal of Adhesion and Interface
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• v.3 no.2
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• pp.45-52
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• 2002

기존의 점착제 합성방법에서 탈피하여 용액형 점착제(Solution)의 장점과 입자형 점착제(Emulsion)의 장점을 동시에 보유한 NAD (Non-Aqueous Dispersion Polymer)를 합성하였다. NAD는 메탄올 분위기에서 6개월 이상의 분산 안정성을 유지하였다. NAD는 용액에서 입자형 고분자의 형태를 이루고 있음을 도공 공정에서 확인하였다. 또한 기존의 아크릴 점착제의 장점과 고무계점착제의 장점을 결합한 고분자량의 점착제, GP (Graft Polymer)를 합성하였다. GP는 자체가 매우 높은 분자량을 보유하여 가교제의 첨가 없이도 우수한 물성을 나타내었다. GP는 일반적으로 고 분자량의 고분자에서 나타나는 Weissenberg effect 현상을 나타내었다. 이들의 점착제로 응용시 각각의 물성을 비교하여 나타내었다.

• Journal of Adhesion and Interface
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• v.7 no.4
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• pp.18-23
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• 2006

The influence of the notch length on the stress distribution of mid-bondline and adherend was investigated using elasto-plastic finite element method. The results from the simulation showed that peak stress of mid-bondline decreased markedly as adherend with notch in the middle of lap zone, and the stress in the middle of joint with low stress originally increased evidently. All the peak stresses decreased firstly and increased again as the length of notch increased. The relative higher peak stress appeared at the point near the notch of adherend where might be failed previously during the loading procedure.

• Journal of Adhesion and Interface
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• v.8 no.1
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• pp.28-33
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• 2007

It is a main trend not to use organic solvents in the adhesive industry from the recent environmental and safe points of view. For example, water-based, hot-melt, or UV curable adhesives are being investigated. Several different kinds of tackifiers that are formulated in the adhesives in order to give them more functional properties like initial tack and higher adhesion, etc., have been proposed to meet the recent trend. Firstly, the characteristics and fundamental properties of the respective materials are presented. In Japan, the trend to develop the water-based adhesives is most remarkable. While the environmental regulations are getting harder, Arakawa Chemical has been spending a lot of energy for the research, and developed toluene-free and solvent free tackifier dispersions that are presented precisely.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.75-78
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• 2005

Using a low-energy Ar+ ion-beam with and without reactive gases, polymers such as chemically stable poly(ether ether ketone) (PTFE) and poly(ether ether ketone) (PEEK) films were modified to have special surface features. The adhesion strength between the polymers and the copper was significantly improved because of both changes in the surface topography and chemical interactions due to polymer surface functionalization (oxidation and amination). The surface modification altered the failure mode from adhesive failure for the unmodified polymer/Cu interface to cohesive failure for the surface-modified polymer/Cu layer interface..