• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.34-41
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• 2002

This study investigated the thermogravimetric analysis of two types of cured tannin-based adhesives from wattle and pine, with three hardeners of paraformaldehyde, hexamethylenetetramine and TN (tris(hydroxyl)nitromethan), at a temperature of 170℃ and a heating rate of 5, 10, 20 and 40℃/min for 10 minutes. The 5 minutes cured wattle tannin-based adhesive with each hardener at 170℃ was also tested to compare the degree of curing. It was found that thermogravimetric analysis could be used to measure the degree of curing of a thermosetting adhesive. The TG-DTG curves of all the adhesive systems were similar and showed three steps in a similar way to a phenolic resin. This means that each adhesive system is well cross-linked. However, a high thermal decomposition rate was shown at 150 to 400℃ in the case of the pine tannin sample with TN (tris(hydroxyl)nitromethan). The Flynn & Wall expression was used to evaluate the activation energy for thermal decomposition. As the level of conversion (𝛼) increased, the activation energy of each system increased. The activation energy of the wattle tannin-based adhesive with paraformaldehyde was higher than the others.

• Composites Research
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• v.30 no.3
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• pp.169-174
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• 2017

Demand of glass fiber reinforced composites (GFRC) increased with developing aircraft and defense industries using resin transfer molding (RTM) process to produce complex product. In this research, wetting, interfacial, and mechanical properties were evaluated with different Cross-linking Density by Molecular Weight of Hardener. Epoxy resin as matrices was used bisphenol-A type and amine-type hardeners with different molecular weight. Specimens were manufactured via RTM and wetting property of resin and glass fiber (GF) mat was evaluated to viscosity of epoxy and injection time of epoxy matrix. Mechanical property of GFRC was determined via flexural strength whereas interfacial properties were determined by interlaminar shear strength (ILSS) and interfacial shear strength (IFSS). The difference in mechanical property depends upon the fiber weight fraction (wt %) of GFRC by RTM as well as the different Molecular Weight of Hardener.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.107-115
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• 2016

In this study, the bond strength of metal spraying system by surface treatment of concrete (waterproof/corrosion method) in water treatment facilities was evaluated. The results showed that the system with Sa-P-R-(S) (sanding-perviousness surface hardener-surface roughness agent-metal spraying-sealing) led to the desirable performance. The bond strength, the coefficient of water permeability and air permeability were 3.7MPa, $0.68{\ast}10^{-8}cm/sec$, and $0.45{\ast}10^{-16}m^2$, respectively. In scanning electron microscope analysis, the microstructure of specimen coated with perviousness surface hardener was much denser than that without it. Therefore, the specimen coated with sanding-perviousness surface hardener-surface roughness agent-metal spraying-sealing had the best bond performance and was the most suitable system to concrete surface in water treatment facilities.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.80-87
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• 2020

The purpose of this study is to investigate the physical properties and self-healing effects of hardener-free epoxy-modified mortars(EMMs) using ground granulated blast furnace slag(GGBFS). The EMMs with GGBFS were prepared with various polymer-binder ratios and GGBFS contents, and tested for strengths, adhesion in tension, water permeation and self-healing effects. The conclusions obtained from the test results are summarized as follows. The compressive strength of the EMMs with GGBFS is reduced with increasing polymer-binder ratios because of reduction of the degree of hardening in the EMMs, and is somewhat inferior to that of unmodified mortars. In the flexural and tensile strengths, the flexural strength of the EMMs is almost constant with increasing polymer-binder ratios. However, the tensile strength of the EMMs is gradually increased with increasing polymer-binder ratios. Regardless of the GGBFS contents, the adhesion in tension of the EMMs increases sharply with increasing polymer-binder ratios. The water permeation of the EMMs is remarkably reduced with increasing polymer-binder ratios and GGBFS contents. The self-healing effect of the hardener-free EMMs with GGBFS is improved with increasing water immersion period at a GGBFS content of 20%.

• Journal of Conservation Science
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• v.36 no.6
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• pp.475-482
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• 2020

In this study, we synthesized rosin-based epoxy resin and manufactured two components adhesives and epoxy putty using this epoxy resin. This study manufactured main element of adhesives for enabling it to form epoxide group by letting epichlorohydrin react to maleic anhydride modified rosin, and used room temperature curing type triethylenetetramine for hardener. The ratio between main element and hardener of of manufactured adhesives was 100 : 20, and main element and hardener of filling material were manufactured as clay type by mixing them with filler. Manufactured undiluted adhesives and filling material showed very stable result in the adhesive strength (3.06 MPa) and ultraviolet irradiation, showing outstanding result comparing to existing restoration adhesives. And it is considered a material having reversibility as it was dissolved in organic solvents such as acetone and toluene after being hardened, which showed a result that solved part of possible problems caused by restoration. As a result of use and application of manufactured adhesives and filling material for actual wood crafts, they showed excellent results in workability, stability, removability etc., and this study confirmed that the material can be used for and applied to various fields.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.95-98
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• 2003

Polymeric composite materials on the basis of some industrial wastes are obtained. Some physical parameters of experimental samples are determined. The analysis of exploitative properties of these polymer composite materials allows recommending them as a heat-insulating material in constructions.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.1088-1090
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• 2002

In this study, a new processing route of barrier ribs for the plasma display panels was attempted. A slurry containing ceramic powders for the barrier ribs, binder, hardener, and other additives, was molded into a PDMS mold by capillary infiltration process. The molded slurry was cured prior to mold removal. It was demonstrated that the process can fabricate successfully the cell type barrier ribs of PDP.

• Journal of the Korea Safety Management & Science
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• v.2 no.3
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• pp.141-150
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• 2000

This study aim is analysis device development for design of experiment with calcium chloride relation used a hardener to search cause of product crack, product reliability improvement building data-base program for computer system of mixture rate, product improvement, and new product development.

• Composites Research
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• v.26 no.4
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• pp.265-272
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• 2013

Fiber-reinforced plastic (FRP) is applied to fabricate the main structures of composite boats. Most of them are made from molds. These products deform after releasing from the mold and they also deform in high temperature environment. Therefore, experimental investigation and evaluation of deformation of laminated composite structures under various manufacturing and working conditions are necessary. The specimens of L-shape and curveshape were made from unsaturated polyester resin and fiberglass material. Input factors (independent variables) are percentage of hardener and manufacturing temperature and four levels of working temperature and output factor is the deformation which is measured on these specimens. From the results, it was observed that the higher the hardener rate and temperature, the lower the deformation. When the working temperature increased, the specimens showed great variations for the initial deformation values. Besides, the values of deformation or input factors could be predicted by regression equations.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.579-585
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• 2017

Acrylic resins containing tertiary amine were synthesized by a radical polymerization of monomers including n-butyl acrylate (BA), methyl methacrylate (MMA), n-butyl methacrylate (BMA) and dimethylaminoethyl methacrylate (DMAEMA), and diethylaminoethyl methacrylate (DEAEMA) containing tertiary amine. Synthesized acrylic resins were applied to develope coatings of acrylic resins containing tertiary amine. And ${\gamma}$-glycidoxypropyl trimethoxysilane (GPTMS) or ${\gamma}$-glycidoxypropyl triethoxysilane (GPTES) was used as hardener. Developed coatings were white colored ones to use titanium dioxide and were hardened with hardener for measuring their physical properties. Measured physical properties were basic properties, adhesivity and weatherability. As a result, developed acrylic resins coatings containing tertiary amine showed excellent adhesivity on various substrates and also showed the same result on weatherability on dry weather condition.