• Journal of Adhesion and Interface
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• v.1 no.1
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• pp.15-22
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• 2000

To prepare acrylic type pressure-sensitive adhesive, quarter polymers were synthesized from butylacrylate (BA), 2-ethylhexylacrylate (2-EHA), methyl methacrylate (MMA), 2-hydroxyethylmethacrylate (2-HEMA). The quarter polymer was identified by FT-IR. Molecular weight was measured by Gel Pearmeation Chromatograhy. Also, viscosity, solid content and peel strength were investigated. The peel strength was $160g_f/25mm$ when the volume ratio of feed monomer to solvent was 1.3:1 and the ratio was relevant to commercial usage. The pot life of adhesive was 30 s at the 50 m/min of heat treatment rate, and it indicated that the minimum drying time was 30 s. Not only weathering resistance keep up peel strength $160{\sim}180g_f/25mm$ after 1000 h, but also no residual remains.

• Current Photovoltaic Research
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• v.7 no.3
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• pp.65-70
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• 2019

As a demand of higher power photovoltaic modules, shingled, multi-busbar, half-cell, and bifacial techniques are developed. Multi-busbar module has advantage for large amount of light havesting. And, half-cell is high power module for reducing resistive losses and higher shade tolerance. Recently, researches on multi-busbar is focused on reliability according to adhesion and intermetallic compound between Sn-Pb solder and Ag electrode. And half-cell module is researched to comparing with full-sized cell module for structure difference. In this study, we investigated the factors affecting to efficiency and adhesion of multi-wires half-cell module according to wire thickness, solder thickness, and flux. The results of solar simulator and peel test was that peel strength and efficiency of soldered cell is not related. But samples with flux including high solid material showed high efficiency. The results of FE-SEM and EDX line scan on cross-section between wire and Ag electrode for different flux showed thickness of solder joint between wire and Ag electrode is increasing through solid material increasing. Flux including high solid material would affect to solder behavior on Ag electrode. Higher solid material occurred lower growth of IMC layer because solder permeate to sider of wire ribbon than Ag electrode. And it increased fill factor for high efficiency. In soldering process, amount of solid material in flux and solder thickness are the factor related with characteristic of soldered photovoltaic cell.

• Journal of Adhesion and Interface
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• v.24 no.2
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• pp.60-63
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• 2023

The AlGaN/GaN heterostructure has high electron mobility due to the two-dimensional electron gas (2-DEG) layer, and has the characteristic of high breakdown voltage at high temperature due to its wide bandgap, making it a promising candidate for high-power and high-frequency electronic devices. Despite these advantages, there are factors that affect the reliability of various device properties such as current collapse. To address this issue, this paper used metal-organic chemical vapor deposition to continuously deposit AlGaN/GaN heterostructure and SiN passivation layer. Material and electrical properties of GaN HEMTs with/without SiN cap layer were analyzed, and based on the results, low-frequency noise characteristics of GaN HEMTs were measured to analyze the conduction mechanism model and the cause of defects within the channel.

• Journal of Ginseng Research
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• v.47 no.4
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• pp.493-505
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• 2023

In recent years, an increasing number of reports have explored the wound healing mechanism of these two traditional Chinese herbal medicines- Panax ginseng and Panax notoginseng, but there is no systematic research on the related core functions and different mechanisms in the treatment of wound healing up to now. Based on network pharmacology and meta-analysis, the present work aimed to comprehensively review the commonality and diversity of P. ginseng and P. notoginseng in wound healing. In this study, a wound healing-related "ingredients-targets" network of two herbs was constructed. Thereafter, meta-analysis of the multiple target lists by Metascape showed that these two medicines significantly regulated blood vessel development, responses to cytokines and growth factors and oxygen levels, cell death, cell proliferation and differentiation, and cell adhesion. To better understand the discrepancy between these two herbs, it was found that common signaling pathways including Rap1, PI3K/AKT, MAPK, HIF-1 and Focal adhesion regulated the functions listed above. In parallel, the different pathways including renin-angiotensin system, RNA transport and circadian rhythm, autophagy, and the different metabolic pathways may also explained the discrepancies in the regulation of the above-mentioned functions, consistent with the Traditional Chinese Medicine theory about the effects of P. ginseng and P. notoginseng.

• Journal of Conservation Science
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• v.35 no.6
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• pp.681-688
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• 2019

In this study, the characteristics of natural and synthetic adhesives used in woodcraft were evaluated. The pattern of deterioration of wood and adhesives according to changes in temperature and humidity were compared. For materials, one type of anlmal glue, three kinds of polyvinyl acetate adhesives, one type of epoxy adhesive and one type of zelkova wood were selected. Characteristics of physical and chemical characteristics, weather resistance and drying speed assessment were carried out. The adhesion characteristic evaluation showed that the adhesion strength of anlmal glue and one type of polyvinyl acetate adhesive were 6.54 N/㎟ and 7.01 N/㎟, pH meter of anlmal glue and polyvinyl acetate adhesives was pH 7.03 and pH 3.32-3.59 which were range of available as an adhesive. According to the test results of weather resistance, epoxy adhesives had the highest decreasing value in adhesion strength after deterioration. In the reversible test of the adhesive, it was found to be highly reversible in NaOH, a soluble solvent excluding epoxy, but attention is required when using the wood since it may show discoloration during processing.

• 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.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.121-128
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• 2014

PURPOSES : The objective of this study is to evaluate the tack-coating material's properties using the bitumen bond strength(BBS) test and damping test as function of changed curing times. In this study, bonding strength tests were performed according to the curing time of tack coating materials. METHODS : In order to investigate bonding characteristic of tack coating materials, the Pneumatic Adhesion tensile Testing Instrument(PATTI) device is used to measure the bond strength between the tack coating materials and aggregate substrate based on the AASHTO TP-91. Also, damping test as in situ test was used to determine an appropriate traffic openting time for construction vehicle. Four different tack-coating materials were used in this study. The BBS tests were performed a one hour curing and testing temperatures of $5^{\circ}C$, $15^{\circ}C$, and $25^{\circ}C$. Damping test was conducted at 30min, 60min, 90min, and 120 min of curing times with temperatures of $20^{\circ}C$ and $30^{\circ}C$. RESULTS and CONCLUSIONS : The BBS test results show various bond strength as function of tack coat materials. At the same testing condition, A tack coat material shows almost two times higher than D tack coat materials although both materials are satisfied the criteria of material's physical properties. Also, Dampting test results shows similar trend with BBS test result. The damping test result was significantly changed as function of tack coat materials. Based on this study, the tack coating material's curing time is very important. Therefore, both curing time and the bond strength's characteristic has to be considered in standard specification.

• Corrosion Science and Technology
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• v.8 no.5
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• pp.197-202
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• 2009

The high toxicity of wax, oil, varnish and volatile corrosion inhibitor(VCI) corrosion inhibitors lead to an increasing interest in using non-toxic alternatives such as anti-corrosive film. This study aims to investigate the possibility to use acryl based anti-corrosive film as a substitution of toxic corrosion inhibitors. Acryl emulsions were polymerized by several acryl monomers(acrylonitrile(AN), n-butyl acrylate(nBA), methylmethacrylate(MMA) and glycycyl methacrylate(GMA)), non-toxic corrosion inhibitor, crosslinking agents(diethylene glycol dimethacrylate(DEGDA)) and various additives in order to apply substrate of anti-corrosive film. Acryl emulsion for anti-corrosive film(AeACF) as a substrate of corrosion inhibitor film has excellent removal characteristic at above $25^{\circ}C$. The crosslinked by DEGDA in a range of above 4 wt% content anti-corrosive film can easily remove from the metal surface by using hands because it kept a balance of cohesion and adhesion strength. Anti - corrosive performance of AeACF is better than anti-corrosive oil by corrosion rate test, which was measured $54.3mg/dm^2$ day(MDD) and $142.9mg/dm^2$ day, respectively. Anti-corrosive film consisting of acryl monomers and inorganic anti-corrosive ingredients did not emit any toxic pollutants by gas chromatography. Thus it is estimated that acryl based anti-corrosion film can substitute toxic corrosion inhibitors.

• Elastomers and Composites
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• v.29 no.5
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• pp.444-452
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• 1994

Emulsion graft copolymerizations of vinyl monomers, butyl acrylate(BA), methyl methacrylate(MMA), 2-ethylhexyl acrylate (EHA), glycidyl methacrylate (GMA), 2-hydroxyethyl methacrylate(HEMA), methacrylonitrile(MAN), dimethylaminoethyl methacrylate(DAMA) or 2-vinyl pyridine(VP), onto carboxyl-terminated SBR latex were carried out under different experimental conditions. In case of synthesizing SBR-g-poly(butyl acrylate), the degree of grafting was increased with increasing the amount of emulsifier, polymerization temperature and the amount of initiator. Pull-out strength of resorcinol-formaldehyde-latex(RFL) adhesives formulated with modified latexes was very higher than that of RFL adhesive formulated with ungrafted latex. When the modified latexes with GMA, HEMA, MAN, DAMA or VP were used, the break occurred at cords. Peel strength of RFL adhesives formulated with SBR-g-poly(GMA), SBR-g-poly(HEMA) or SBR-g-poly(VP) was higher by about 1.3 times than that of RFL adhesives formulated with unmodified SBR against nylon cord and was higher by about 2.0 times against polyester cord.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.5 s.142
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• pp.671-679
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• 2005

Chitosan is the affinitive finishing agent and gives susceptible effect in textile finishing. In order to examine the modification of polyester fabric treated with chitosan, we observed the characteristic of polyester fabric surface and measured its physical properties. For the purpose of confirming the adhesion of cationic material, we made a comparative study on anionic acid dye. The fabric was treated with crosslinking agent after chitosan finishing. Glutardialdehyde as crosslinking agent was used to improve the fixation rate of chitosan on the polyester fabric. And the US value was increased according to increasing of chitosan concentration. As the concentration of crosslinking agent was increased, whiteness index of the fabric chitosan treated was increased. Moisture regain of the fabric treated with $1\%$ chitosan was doubled and that treated with $2\%$ chitosan was tripled comparing with original fabric. Tensile strength of the chitosan treated fabric had been an increase of $10\%$ compared with alkali treated fabric and crease resistance decreased regardless of chitosan concentration.