• Title/Summary/Keyword: powder of resin

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Examples of clinical applications of flexible composite resin that is quite different from conventional composite resins (Conventional composite resin과 사뭇 다른 flexible composite resin의 여러 임상 활용 예)

  • Kim, Woohyun
    • Journal of the Korean Academy of Esthetic Dentistry
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    • v.29 no.2
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    • pp.92-102
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    • 2020
  • Bond-Fill SB is made of powder/liquid, and the flowability can be controlled by adjusting the amount of liquid in the brush. Thanks to the strong catalyst called TBB, it has the advantage of being able to polymerize even in the presence of water and oxygen. Also, since it contains 4-META, it has the advantage of being able to adhere to metals and ceramics with appropriate surface treatment. If you fully understand these advantages, you can actively utilize them in cases where it is difficult to treat with conventional composite resin.

Chloride Penetration Properties of Portland Cement Mortar Substituted with Anion Exchange Resin Powder (음이온교환수지 분말이 치환된 포틀랜드 시멘트 모르타르의 염소이온 침투 특성)

  • Lee, Yun-Su;Lim, Seung-Min;Park, Jang-Hyun;Jung, Do-Hyun;Lee, Han-Seung
    • Journal of the Korea Institute of Building Construction
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    • v.20 no.1
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    • pp.1-9
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    • 2020
  • Chloride ion, which penetrates into the cement composites from the outside, generally diffuses by the concentration gradient. Chloride ions are adsorbed by the chemical reaction with cement hydrates. Recent studies have shown that anion exchange resin (AER) powder can effectively adsorb the chloride ion in the cement composites, and thus, the cement composites containing AER have a high chloride adsorption capacity and a good resistance for chloride penetration. In this study, the chloride adsorption ability of the AER powder was investigated under the conditions of distilled water and calcium hydroxide saturated solution to determine if the AER powder is less effective to increase the chloride adsorption ability after grinding process. The chloride adsorption ability of AER powder was compared with the previous research about the chloride adsorption of AER bead. In addition, the compressive strength, chloride diffusion coefficient (using NT Build 492 method), and the chloride profile of cement mortar substituted with AER powder were investigated. There was no decrease in the chloride adsorption capacity of AER powder but increase in the kinetic property for chloride adsorption after the grinding process. The AER powder could absorb the chloride ion in the mortar quickly, and showed better chloride ion adsorption ability than the cement hydrates.

STRENGTH OF GLASS FIBER REINFORCED PMMA RESIN AND SURFACE ROUGHNESS CHANGE AFTER ABRASION TEST

  • Lee, Sang-Il;Kim, Chang-Whe;Lim, Young-Jun;Kim, Myung-Joo;Yun, Suk-Dae
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.3
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    • pp.310-320
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    • 2007
  • Statement of the problem. 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 acrylic resin using glass fibers, have been suggested over the years. But problems such as poor workability, rough surface, poor adhesion of glass fiber resin complex are not solved yet. Purpose. The aim of the present study was to investigate the effect of short glass fibers on the transverse strength of heat-polymerized denture base acrylic resin and roughness of resin complex after abrasion test. Material and methods. To avoid fiber bunching and achieve even fiber distribution, glass fiber bundles were mixed with acrylic resin powder in conventional mixer with a non-cutting blade, to produce the glass fiber($10{\mu}m$ diameter, 3mm length, silane treated) resin composite. Glass fibers were incorporated at 0%, 3%, 6% and 9% by weight. Transverse strength were measured. After abrasion test, surface roughness was evaluated and scanning electron microscope view was taken for clinical application. Results. 1. 6% and 9% incorporation of 3mm glass fibers in the acrylic resin enhanced the transverse strength of the test specimens(p<0.05). 2. Before abrasion test, incorporation of 0%, 3%, 9% glass fiber in the resin showed no dirrerence in roughness statisticaly(p>0.05). 3. After abrasion test, incorporation of 0%, 3%, 6% glass fiber in the resin showed same surface roughness value statistically(p>0.05). 4. In SEM, surface roughness increased as the percentage of the fibers increased. 5. In the areas where glass fiber bunchings are formated, a remarkably high roughness was noticed. Conclusion. 6% and 9% addition of silane-treated short glass fibers into denture base acrylic resin increased transverse strength significantly. Before and after abrasion test, incorporation of 0%, 3%, 6% glass fiber in the resin showed same surface roughness value statistically.

Influence of Water Volume on Particle Characteristics of Iron Powder with Insulated Coating for a Compacted Magnetic Core

  • Funato, Norikazu;Yamamoto, Masayuki
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.160-161
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    • 2006
  • Seasonal changes have been recognized in particle characteristics and forming characteristics of iron powder with insulated coating for a compacted magnetic core because of its high hygroscopicity, due to its phosphate coating and resin binder additives. For this reason, particle characteristics and molding characteristics of the powder with diverse water absorbtivity have been studied. The result shows that the higher the volume of absorbed water, the worse the fluidity becomes, resulting in the reduction in both springback during the molding process and expansion reduction after the heat treatment. The requirement on dimension accuracy for the finished product can be satisfied with an additional drying process on the material powder, which contributes to maintain its water volume constant.

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Studies on the Extending of Plywood Adhesives used Foliage Powder (낙엽분말(落葉粉末)을 이용(利用)한 합판용(合板用) 접착제(接着劑)의 증량(增量)에 관(關)한 연구(硏究))

  • Kim, Jong-Man;Bark, Jong-Yeol;Lee, Phil-Woo
    • Journal of Korean Society of Forest Science
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    • v.42 no.1
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    • pp.83-100
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    • 1979
  • It was planned and performed to study the possibility on the use of inexpensive and easily acquirable foliage powder, which processed by pulverizing after dried, instead of imported expensive wheat flour for the extending of plywood adhesives. Pine leaves of softwood trees, Poplar, Oak and Sycamore leaves of broad leaved species were selected and harvested to pulverize into the minute foliage powder. The harvested foliages from each selected species were pulverized into 40 mesh particles after dried at $100{\sim}105^{\circ}C$ condition during 24 hours in drying oven. To compare the extending effect of plywood adhesives with these foliage powders 100 mesh wheat flour using at current plywood industry was also prepared. Foliage powder and wheat flour were extended into 10, 20, 30, 50 and 100% to the urea and phenol formaldehyde resin. After plywoods were processed by the above extending method shear strength of extended plywoods were analyzed and discussed. The results obtained at this study are as follows: 1) Among 10% extensions of urea formaldehyde resin plywood, dry shear strength of plywood extended by wheat flours was the highest and that of non-extended plywood the next. Plywood extended with foliage powder showed the lowest dry shear strength. The order of dry shear strength of plywoods extended by foliage powder was that of Oak foliage powder extension, the best, that of Sycamore, that of Pine, and that of Poplar. 2) Among 20% extensions of urea formaldehyde resin plywood, plywood extended by wheat flour showed the highest dry shear strength, and the next was plywood by Poplar foliage powder. All these two showed higher dry shear strength than non-extension plywoods. Except Poplar, dry shear strength of foliage powder extension plywoods was bad, but the order of dry shear strength of plywoods extended by foliage powder was Pine, Poplar and Oak. 3) In the case of 30% extensions of urea formaldehyde resin plywood, dry shear strength of wheat flour extension was the highest and non-extension the next. Dry shear strength of foliage powder extension plywoods was poor with a rapid falling-off in strength. 4) Among 50% and 100% extensions of urea formaldehyde resin plywood, only wheat flour showed excellent dry shear strength. In the case of foliage powder extension, low dry shear strength showed at the 50% extension of Pine and Poplar, and plywoods of 50% extension of Oak foliage powder delaminated without measured strength. All plywoods of 100% foliage powder extension delaminated, and then shear strength were not measured. 5) Among wet shear strength of 10% extensions of urea formaldehyde resin plywood, wheat flour extension was the highest as in the case of dry shear strength, and non-extension plywood the next. Except Poplar foliage extension, all foliage powder extension plywoods showed low shear strength. 6) Wet shear strength of plywoods of 20% extension lowered in order of non-extension plywood, plywood of wheat flour extension and plywood of foliage powder extension, but other plywoods of foliage powder extension except plywoods of Poplar and Oak foliage powder extension delaminated. 7) Wet shear strength of 30% or more extension of urea formadehyde resin plywood were weakly measured only at 30% and 50% extension of wheat flour, and wet shear strength of plywoods extended by foliage powder were not measured because of delaminating. 8) Dry shear strength of phenol formaldehyde plywoods extended by 10% wheat flour was the best, and shear strength of plywoods extended by foliage powder were low, but the order was Oak, Poplar, and Pine. Plywood of Sycamore foliage powder extension delaminated. 9) In the case of 20% extensions of phenol formaldehyde resin, dry shear strength of plywood extended by wheat flour was the best, but plywood of Pine foliage powder extension the next, and the next order was Oak and Poplar foliage powder. Plywood of Sycamore foliage powder extension delaminated. 10) Among dry shear strength of 30% extensions of phenol formaldehyde plywood, that of Pine foliage powder extension was on the rise and more excellent than plywood of wheat flour extension, but Poplar and Oak showed the tendency of decreasing than the case of 20% extension. Plywood of Sycamore foliage powder extension delaminated. 11) While dry shear strength of 50% and 100% extension plywoods were excellent in the case of Pine foliage powder and wheat flour extension, that of hardwood such as Poplar, Oak, and Sycamore foliage powder extension were not measured because of delaminating. 12) As a filler the foliage powder extension of urea formaldehyde resin is possible up to 20% with Poplar foliage powder. And also as an extender for phenol formaldehyde resin, Pine foliage powder can be added up to the same amount as that in the case of wheat flour.

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Effect of Phenolic Resin According to Relative Humidity on Submerged Entry Nozzle with ZrO2-C System in Fabrication Process (ZrO2-C계 침지노즐 제조시 상대습도에 따른 바인더용 페놀수지의 영향)

  • Yoon, Sang-Hyeon;Kim, Jang-Hoon;Kim, Ju-Young;Lee, Hee-Soo;Koo, Young-Seok
    • Journal of the Korean Ceramic Society
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    • v.48 no.4
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    • pp.293-297
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    • 2011
  • The thermodynamic behavior of phenolic resin was investigated to verify the relation between the properties of porous ceramics with $ZrO_2$-C system for submerged entry nozzle and the characteristics of phenolic resin with various relative humidity. The green and the sintered density were decreased between 25% and 50% relative humidity, whereas they were gradually enhanced above 50% relative humidity. The highest value of apparent porosity was 20.1% and the minimum compressive strength was 69MPa in the specimen using the powder exposed to 50% relative humidity. As a result of thermal analysis for phenolic resin, the shift of endothermic peak to low temperature and the reduction of exothermic peak were observed, and the peaks corresponded to melting and curing of phenolic resin, respectively. The melting and the curing of phenolic resin generate the change of green density, and it can affect the properties of submerged entry nozzle.

The Variation of Packing Density According to Powder Size Distribution and Epoxy Resin in Soft Magnetic Composite (연자성 복합체에서 파우더 크기 분포와 Epoxy Resin에 따른 Packing Density 변화)

  • Lee, Chang Hyun;Oh, Sea Moon;Shin, Hyo Soon;Yeo, Dong Hun;Kim, Jin Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.12
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    • pp.782-787
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    • 2017
  • There is growing interest in power inductors in which metal soft magnetic powder and epoxy resin are combined. In this field, the process technology for increasing the packing density of magnetic particles in an injection molding process is very important. However, little research has been reported in this regard. In order to improve the packing density, we investigated and compared the sedimentation heights of pastes for three types of soft magnetic alloy powders as a function of the mixing ratios and the type of resin used. Experimental results showed that the packing density was the highest (71.74%) when the mixing ratio was 80 : 16 : 4 (Sendust : Fe-S : CIP) according to the particle size using an SE-4125 resin. In addition, the packing density was found to be inversely related to the layer separation distance. As a result, it was confirmed that the dispersion of solid particles in the paste was important for curing; however, the duration of the curing process can greatly affect the packing density of the final composite.

Nanoparticle Size Effect on Mechanical Properties of Carbon Fiber-reinforced Polymer Composites (탄소섬유강화 에폭시수지의 기계적 성질에 미치는 나노입자크기의 영향)

  • Moon, Chang-Kwon;Kim, Bu-Ahn
    • Journal of Ocean Engineering and Technology
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    • v.29 no.2
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    • pp.186-190
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    • 2015
  • $TiO_2$ nanoparticles can be used to improve the performance of carbon fiber-reinforced epoxy resin composites. In this study, the effect of the size of $TiO_2$ nanoparticles on the mechanical properties of carbon fiber-reinforced epoxy resin composites was investigated. The size of the $TiO_2$ nanoparticles was easily controlled using heat treatment. The size of the $TiO_2$ nanoparticles for this study were20nm, 100nm, and 200nm. Three types of carbon fibers with different diameters were also used in this study. The carbon fiber-reinforced epoxy resin composites with 20-nm $TiO_2$ powder showed the highest tensile strength compared to the other types of CFRP, regardless of the fiber maker or fiber diameter. The size of the $TiO_2$ powder and the diameter of the carbon fiber strongly affected the interfacial properties of all kinds of CFRP in this study.

Buckling behaviours of functionally graded polymeric thin-walled hemispherical shells

  • Uysal, Mine U.
    • Steel and Composite Structures
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    • v.21 no.4
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    • pp.849-862
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    • 2016
  • This paper investigates the static buckling behaviours of Functionally Gradient Polymeric Material (FGPM) shells in the form of hemispherical segment. A new FGPM model based on experimental was considered to investigate the buckling problem of thin-walled spherical shells loaded by the external pressure. The spherical shells were formed by FGPM which was produced adding the two types of graphite powders into epoxy resin. The graphite powders were added to the epoxy resin as volume of 3, 6, 9, and 12%. Halpin-Tsai and Paul models were used to determine the elastic moduli of the parts of FGPM. The detailed static buckling analyses were performed by using finite element method. The influences of the types and volume of graphite powders on the buckling behaviour of the FGPM structures were investigated. The buckling loads of hemispherical FGPM shells based on Halpin-Tsai and Paul models were compared with those determined from the analytical solution of non-graphite condition existing for homogeneous material model. The comparisons between these material models showed that Paul model was overestimated. Besides, the critical buckling loads were predicted. The higher critical buckling loads were estimated for the PV60/65 graphite powder due to the compatible of the PV60/65 graphite powder with resin.

Improvement of Pot Life in the Epoxy Resin-based Adhesive Formulation by Size Control and Coating of Curing Accelerator Powders (경화촉매 분말의 입도조절 및 표면코팅에 의한 에폭시 레진 기반 혼합조성의 상온 보관특성 개선)

  • Lee, Jun-Sik;Hyun, Chang-Yong;Lee, Jong-Hyun
    • Journal of Powder Materials
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    • v.15 no.2
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    • pp.119-124
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    • 2008
  • To increase pot life in the formulation mixed with bisphenol F epoxy resin, anhydride-based curing agent, and imidazole-based curing accelerator powders as a paste material for high-speed RFID chip bonding, size variation of the imidazole-based powders and a coating method of the powders were adopted in this study. In experiment with regard to the size variation, the pot life was not outstandingly increased. Through the idea using the coating method, however, the pot life was increased up to 4.25 times in comparison with the addition of initial imidazole-based powders. Consequently, successive bonding of RFID chip could be performed with very short time of 5sec using the suggested formulation having improved pot life.