• Journal of the Korean Society of Clothing and Textiles
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• v.12 no.1 s.26
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• pp.27-35
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• 1988

In order to investigate a practical application of the fibrous adsorbent to heavy metal ions, acrylic fibers were treated with the hydroxylamine solution that was producted by hydroxylamine hydrochloride and potasium hydroxide in a condition of strong alkaline and $70^{\circ}C$. The adsorption mechanism of copper(2) ion on the fibrous adsorbent, that is hydroxylaminated acrylic fibers, was studied. The adsorption of copper(2) ion was explained in terms of the activated adsorption that are formed the complex with the ligand, such as C=N, N-H, NHOH, on the surface of the adsorbent. The activation energy was evaluated to be 3.8 Kcal/mol. and the times of adsorption equilibrium was approximately 10 minutes. The uptake of copper(2) ion was found to be effected with the increase of temperatures and the pH dependence.

• Fibers and Polymers
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• v.7 no.3
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• pp.223-228
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• 2006

Hydrogels of semi-interpenetrating polymer networks (semi-IPNs) were prepared by two step reactions. Dimethylaminoethyl methacrylate (DMAM) and poly(ethylene glycol)-dimethacrylate (PEGDM) were copolymerized to yield hydrogels, and then acrylic acid (AA) monomer were adsorbed in the hydrogels followed by polymerization of AA to produce semi-IPNs. The swelling behavior of semi-IPNs depends largely on pH of medium, showing that the degree of swelling of the semi-IPNs exhibits a minimum at pH 6.0. It is observed that the elastic modulus of semi-IPNs is closely related to its swelling behavior.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.6
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• pp.589-598
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• 2001

The fracture of acrylic resin dentures remains an unsolved problem. Therefore, many investigations have been performed and various approaches to strengthening acrylic resin, for example, the reinforcement of heat-cured PMMA resin using glass fibers, have been suggested over the years. The aim of the present study was to investigate the effect of short glass fibers treated with silane coupling agent on the transverse strength of heat-polymerized PMMA denture base resin. To avoid fiber bunching and achieve even fiber distribution, glass fiber bundles were mixed with PMMA powder in conventional mixer whose blade was modified to be blunt. Composite of glass fiber($11{\mu}m$ diameter, 3mm & 6mm length, silane treated) and PMMA resin was made. Transverse strength and Young's modulus were estimated. Glass fibers were incorporated with 1%, 3%, 6% and 9% by weight. Plasticity and workability of dough was evaluated. Fracture surface of specimens was investigated by SEM. The results of this study were as follows 1. 6% and 9% incorporation of 3mm glass fibers in the PMMA resin enhanced the transverse strength of the test specimens(p<0.05). 2. 6% incorporation of 6mm glass fibers in the PMMA resin increased transverse strength, but 9% incorporation of it decreased transverse strength(p<0.05). 3. When more than 3% of 3mm glass fibers and more than 6% of 6mm glass fibers were incorporated, Young's modulus increased significantly(p<0.05). 4. Workability decreased gradually as the percentage of the fibers increased. 5. Workability decreased gradually as the length of the fibers increased. 6. In SEM and LM, there was no bunching of fibers and no shortening of fibers.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.11-12
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• 2003

The reinforcing effect of single wall carbon nanotubes (SWNTs) on polyacrylonitrile (PAN) fiber were investigated. The tensile fracture images of the composite fibers demonstrate that SWNTs are well dispersed in PAN matrix as bundles (ropes) ca. 20nm in thickness. It was found that SWNTs play a role not only to reinforce but also to toughen the PAN fiber by increasing breaking strain as well as modulus and strength of the fiebrs. The composite fibers exhibited improved dimensional stability at elevated temperature compared to the neat PAN fiber.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.7
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• pp.1064-1072
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• 1999

Nylon fabric was grafted for the purpose of the development of detergency against the hemoglobin as a protein soil. By free-radical producing chemical initiator systems the graft using acrylic acid(AA) as a hydrophilic vinyl monomer was performed to change surface energies in the presence of ammonium persulfate(APS) as an initiator and then acrylic acid grafted Nylon was treated with NaOH solution. The surface morphology for Nylon-g-NaAA with changing graft rate were studied by scanning electron microscopy (SEM) The properties of the Nylon such as diameter tenacity elongation contact angle and the hemoglobin removal were also investigated. The diameter of grafted Nylon fiber increased as the graft ratio increased. The tenacity of grafted Nylon also increased with increasing graft ratio up to 15% The elongation however decreased gradually according to graft, The contact angle decreased after graft and alkaline treatment. The amount of hemoglobin on the grafted Nylon increased in proportion to the graft ratio. Hemoglobin was easily removed from grafted Nylon while it was difficult to be removed from ungrafted Nylon. The detergency of hemoglobin for grafted Nylon decreased when the graft ratio exceeded 15% The removal of hemoglobin increased markedly with increasing hemoglobin content and revolution speed. Therefore the removal of hemoglobin was improved due to graft and alkaline treatment.

• Textile Coloration and Finishing
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• v.11 no.2
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• pp.27-37
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• 1999

Polypropylene(PP) films were treated with plasma glow discharge to produce peroxy radicals on the surfaces. The peroxy radicals formed on the PP film surfaces were subsequently used for the graft polymerization of acrylic acid and acrylamide in an aqueous solution by heating, respectively. Introduction of acrylic acid and acrylamide on the PP film could be confirmed by the observation of carbonyl and primary amine absorptions based on carboxylic acid and amide, respectively. And introduction of functional group could be confirmed by weight analysis and ESCA. The water contact angle(90$^{\circ}$) of PP film was constant, irrespective of elapsed time, while plasma-treated and functional monomer-grafted PP films were slowly increased with elapsed time, showing the rearrangement of surface polar groups in air condition. The water contact angle$(90^\circ)$ of PP film was decreased by the plasma treatment$(56^\circ)$ and further decreased by the grafting of acrylic acid$(34^\circ)$ and acrylamide$(37^\circ)$, indicating increased hydrophilicity of the modified surfaces. The water contact angle of plasma-treated PP film increased a little as time elapsing. The half-life periods of surface voltage on acrylic acid-(31sec) and acrylamide-grafted PP(42sec) were significantly decreased when compared to those on PP(950sec) and plasma-treated PP film(241sec). In the experiments using acid, basic and disperse dyes, absorbance and $\Delta{E}$ values of functional monomer-grafted PP films were significantly increased than that of oxygen plasma-treated one.

• Polymer(Korea)
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• v.32 no.6
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• pp.509-515
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• 2008

The aminated polypropylene melt blown ion exchange fibers were synthesized with acrylic acid monomer onto polypropylene melt blown fibers by radiation-induced polymerization and subsequent amination. Degree of grafting was increased with increasing the acrylic acid monomer concentration and total dose. The highest degree of grafting was obtained 140% at a monomer concentration of 20 v/v% acrylic acid and total dose of 4 kGy. Optimum condition of Mohr's salt was 5.0 $\times10^{-3}$ M. Degree of amination was increased with increasing degree of grafting. Water content was about 1.5 times higher than that of trunk polymer. The maximum ion-exchange capacity was 7.3 meq/g which was 2$\sim$3 times higher than a commercial ion exchange fiber. The average pore size was decreased and BET surface area was increased in order of PPmb, PPmb- g- AAc and APPmb- g- AAc. The average pore size and BET surface area of synthesised fibers were $366.1\;{\AA},\;3.71m^2/g,\;143.3\;{\AA},\;4.94m^2/g,\;40.97\;{\AA},\;8.98m^2/g$, respectively.

• Journal of the Korean Society of Clothing and Textiles
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• v.1 no.1
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• pp.25-29
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• 1977

The warmth retentivity of natural and syntheic waddings as bedding stuff, and further, the machanism of heat transmission through conduction, radiation and convection were analysed. The materials used were cotton, silk, and wool as natural waddings, and polyamide, polyester, regular acrylic, conjugate acrylic, regular polyprepylene and conjugate polypropylene as synthetic waddings. The results of this study are as follow: 1. The warmth retentivity is highest in silk. Following silk in descending order is cotton, conjugate acrylic, polyester, regular acrylic, wool, polyamide, conjugate polypropylene and regular polypropylene. There is not any significant relationship between warmth retentivity and the conductivity of the fibers. 2. Transmission by radiation through the fiber waddings is highest in conjugate polypropylene. Following conjugate polypropylene in descending order is regular polypropylene. polyester. polyamide, conjugate acrylic, regular acrylic, wool, cotton, and silk. This is seen to be in nearly reversed order to the abovementioned order of warmth retentivity. In this respect, warmth retentivity with loose fibreous material as in the case of bedding stuff is primarily affected by the interceptive function of the fibers in heat radiation. 3. Warmth retentivity becomes lower with increasing air content of the waddings. This is because heat transmission by radiation incrases as air content increases. The air content increase is due to the fact that the air is unable to intercept heat radiation. In addition, heat transmission accelates in proportion to the increase in convection as the air gap enlarges.

• The Journal of Korean Academy of Prosthodontics
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• v.32 no.3
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• pp.411-430
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• 1994

The denture may be fractured accidentally by an impact while outside the mouth, or may be cracked or broken while in service in the mouth. The latter is generally a fatigue failure caused by repeated flexure over a period of time. This investigation compared the flexural fatigue resistance, the impact force and the transverse strength of two denture base materials with and without the grid strengthener, the T300, the T800 and the Kevlar fiber to evaluate the fracture resistance. The distribution and behavior of fibers across fracture lines were examined by Hi-Scope Compact Microvision System. Through analyses of the data from this study, the following conclusions were obtained. 1. The flexural fatigue resistance, impact strength and transverse strength of high impact strength resin were higher than those of conventional heat polymerizing resin, but statistically there was no significant difference(p>0.05). 2. All specimens with and without the grid strengthener did not show significant differences in the flexural fatigue, the impact and the transverse strength test(p>0.05). 3. All specimens reinforced with the T300, the T800 and the Kevlar fiber showed significant increase of the fatigue resistance and the impact force(p<0.05). 4. All specimens reinforced with the T800 and the Kevlar fiber showed significant increase of the transverse strength(p<0.05). 5. All specimens reinforced with the T300, the T800 and the Kevlar fiber exhibited greenstick fractures. The fibers tended to remain enveloped in the resin, resisting pull-out.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.307-309
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• 2001

최근 기존 섬유의 부가가치를 높인 여러 가지 기능성 섬유들에 대한 관심이 증가하고 있다. 이러한 기능성 섬유들 중에서 항미생물 특성을 가지는 섬유는 의료용 섬유재료 분야(백의, 환자복, 수건, 마스크, 이불, 내의, 카펫 및 커튼 등) 뿐만 아니라, 근래에는 소비자들이 건강과 쾌적한 생활을 매우 중요시함에 따라 다양한 분야에서 그 수요가 급격히 증가하여 왔다. (중략)