• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.763-767
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• 1998

Cholesterol-containing surfactant was synthesized, and it was sonicated with monomer [tetradeca(ethylene glycol) diacrylate] in water to from a vesicle solution. This vesicle solution was dried to construct a membrane which had a molecular multilayer structure. The monomer which stay in this membrane was polymerized with photoinitiation, and then surfactant was extracted by organic solvent. The physical properties of the two dimensional polymer network were measured, and these physical properties are tensile strength, elongation, and swelling.

• Journal of Korean Society of Forest Science
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• v.76 no.2
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• pp.119-126
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• 1987

This study was carried out to elucidate the desirable PEG molecular weight and it's blending methods which can promote the dimensional stabilization of Corpus controversa, Quercus variabilis and Prunus sargentii. The results may be summarized as follows: 1. PEG polymer loading in woods was affected by specific gravity of wood. And the PEG polymer loading was satisfactory except in Quercus variabilis, which shows the blending method of PEG V was proper. 2. Bulking coefficiency of PEG V was high in Corpus controversa and Prunus sargentii, and it is necessary to paint or coat water-proofing wood preservative: for high bulking coefficiency of Quercus variabilis. 3. In the treatment of PEG V, the antishrink efficiency of Prunus sargentii was 82.59% and that of Quercus variabilis 62.79%. 4. Dimensional stabilization of hardwoods did not have apparant relation with PEG blending method. 5. Judging from results, PEG-400 and PEG-1000 would be enough for dimensional stabilization of hardwood having high specific gravity if other factors are considered well.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.8
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• pp.1076-1083
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• 2009

The physicochemical properties of rice flour produced by 3 different grinding methods using various steeping times (3, 6, 9, and 12 hrs) were investigated. Roller mill gave coarse rice flour; the pin mill, intermediate flour; and mixed when both (roller & pin mills) were used. With the increase of steeping times, the rice flours became finer and the contents of crude protein, crude fat and crude ash decreased. Damaged starch was noticeably high in rice flour by roller & pin mills compared to those by roller or pin mills alone. Amylose contents, solubility and swelling power increased as the steeping times increased. Water binding capacity was the highest in roller & pin mills, followed by pin mill. In scanning electron microscope (SEM), pin mill showed distribution of separated fine particles of rice flours. The physicochemical properties of rice flours showed many differences by steeping times of rice and grinding methods. With sufficient steeping times, the rice flours obtained from pin mill were relatively fine having less damaged starch.

• Journal of the Korean Wood Science and Technology
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• v.22 no.4
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• pp.19-25
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• 1994

The purpose of this study was to determine the technical feasibility of making 3-dimensional thin hardboard panels for overlay substitutes of low grade particleboard and plywood panels. Experimental studies were directed at assembling bench-top apparatus, learning the characteristics of different types of lignocellulosic waste papers, for making thin hardboard with several combinations of them with and without resin addition. The raw materials used are waste corrugated cartons, cereal boxes, and old magazines which contain substantial amount of lignin in it. The experimental results showed that satisfactory thin(0.21~0.16cm) hardboard could be made from the residential mixed waste papers that have selected properties comparable to commercial 0.32cm hardboard. The significant mixing ratio effect of the waste papers was present on the thickness swelling, water absorption, linear expansion, and modulus of elasticity including Taber abrasion tests of the thin hardboard made. The mixing ratio of waste papers and resin in the thin hardboard prominently affected the specific gravity of it, which led to affect modulus of elasticity and those physical properties sensitively. And it was shown that the hardboard containing those physical properties can be used for overlay substitutes of low grade plywood and particleboard panels.

• Journal of the Korean GEO-environmental Society
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• v.23 no.3
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• pp.15-22
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• 2022

This study aims to observe the swelling representative rocks in Korea and to suggest improvements in the use of test methods and prior analysis in relation to the weathering of rocks. The swelling test and analysis were performed on the drilling cores obtained for the ground investigation at the domestic highway construction site. For the method of determining the absorption expansion index of rocks, the method proposed in "Standard Methods for Sample Collection and Specimen Preparation" of ISRM and Korean Rock Engineers Standard Rock Test Method was used. The specimen for the measurement of the expansion displacement was cylindrical with a height of 10 cm and a diameter of 5 cm. The existing swelling analysis method evaluates the sensitivity to weathering by using the maximum expansion displacement, but since the classification by bedrock grade is unclear, it is reasonable to use the rate of change of the expansion displacement according to the immersion time. It is necessary to conduct an experiment to distinguish between weathering and fault deterioration. In addition, long-term weathering prediction technology for each cancer type is needed through the expansion displacement analysis of the chemical weathering stage.

• Tunnel and Underground Space
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• v.33 no.4
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• pp.228-243
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• 2023

Bentonite is widely recognized and utilized as a buffer material in high-level radioactive waste repositories, mainly due to its favorable characteristics such as swelling capability and low permeability. Bentonite buffers play an important role in ensuring the safe disposal of radioactive waste by providing a low permeability barrier and effectively preventing the migration of radionuclides into the surrounding rock. However, the long-term performance of bentonite buffers still remains a subject of ongoing research, and one of the main concerns is the erosion of the buffer induced by swelling and groundwater flow. The erosion of the bentonite buffer can significantly impact repository safety by compromising the integrity of buffer and leading to the formation of colloids that may facilitate the transport of radionuclides through groundwater, consequently elevating the risk of radionuclide migration. Therefore, it is very important to numerically quantify the erosion of bentonite buffer to evaluate the long-term performance of bentonite buffer, which is crucial for the safety assessment of high-level radioactive waste disposal. In this technical note, Two-region model is introduced, a proposed model to simulate the erosion behavior of bentonite based on a dynamic bentonite diffusion model, and quantitative evaluation is conducted for the bentonite buffer erosion with this model.

• Resources Recycling
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• v.23 no.1
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• pp.48-57
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• 2014

In this study, we have investigated the influence of the nature of solvent on the grafting reaction of maleic anhydride onto polyethylene wax obtained as a by-product in a high density polyethylene plant. The results show that the grafting ratio in xylene as a solvent was higher than toluene. This is because xylene has excellent monomer solubility, swelling property and miscibility. It has been also observed that grafting degree shows an initial jump in percentage of grafting with increasing amount of solvent, from 0% v/w to 200% v/w giving maximum grafting in 200% v/w and then slightly decreases on further increase in the amount of solvent and becomes almost constant. It can be also seen that gel content was not formed under the use of solvent. It means that solvent prevented cross-linking reaction due to chain transfer reactions to solvent molecules. Studies of melt viscosity at $140^{\circ}C$ showed that viscosity increased after grafting of maleic anhydride onto polyethylene wax.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.88-95
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• 2008

The shrinkage of wood members after construction has been a greater and common concern in wooden buildings with the durability. Particularly, the traditional structure applying solid members actively is easily exposed to the shrinkage that caused by the joints, members, and walls. Moreover, even though domestic larch glulam members are widespread recently in the post-beam construction, the shrinkage (swelling) problem is still the critical defect on the wooden structures by the moisture content change in Korea. Various moisture contents were applied for the specimens to survey the dimensional changes for Japanese larch solid and glulam specimens, and the glulam specimens varied in the number of their laminations. Test results showed that glulam specimens with over 3 bonding layers showed good dimension stabilities. Therefore, to solve the shrinkage problem, sufficient drying fitted to the end-use service conditions should be conducted on the solid or glulam members can be applied.

• Elastomers and Composites
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• v.34 no.4
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• pp.350-359
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• 1999

Conversion and oil-yield of a used automotive tire sample in supercritical decomposition and extraction for three solvents such as water, 28% ammoina solution and ammonia, were compared. Supercritical extraction with ammonia gave the highest conversion and oil-yield at the same temperature and pressure. In this paper, supercritical ammonia was used as major solvent and tetralin acting as hydrogen-donor, was used as cosolvent. As the amount of tetralin increased, oil-yield was Increased. When a tire sample was extracted by supercritical ammonia, oil-yield was 48.8% at $280^{\circ}C$, 22.3MPa. But when the weight ratio of tetralin to tire sample (weight of tetralin/weight of tire sample) was 5, oil-yield was 61.2% at $280^{\circ}C$ and 22.3 MPa. These phenomena indicate that as radicals produced in supercritical decomposition become stable, the polymerization and the second decomposition of products may be inhibited. Supercritical extraction of a tire sample swollen by tetralin gave high oil-yield although the amount of tetralin was a little.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.367-374
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• 2021

In this study, the applicability of mechanochemical process for the manufacture of self-healing admixtures and the effect of mechanochemical process on the self-healing performance were evaluated. The self-healing admixtures were adopted as a highly reactive materials(expansive agent, swelling material and crystal growth agent) for mechanochemical processes. The self-healing admixtures for the mechanochemical process application were evaluated by X-Ray Diffraction and Fourier Transform Infrared Spectroscopy analysis, water permeability performance was used to evaluate self-healing performance of mortar. As a result of the evaluation, the self-healing performance of the WM(With-Mortar)3 sample to which mechanochemical process increased by 4.1% compared to the WM1 sample that was not treated, and the average healing index was 94.3%.