• Title/Summary/Keyword: adhesive layer

Search Result 543, Processing Time 0.031 seconds

Interfacial Adhesion between Screen-Printed Ag and Epoxy Resin-Coated Polyimide (에폭시수지가 도포된 폴리이미드와 스크린 프린팅 Ag 사이의 계면접착력 평가)

  • Park, Sung-Cheol;Kim, Jae-Won;Kim, Ki-Hyun;Park, Se-Ho;Lee, Young-Min;Park, Young-Bae
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.17 no.1
    • /
    • pp.41-46
    • /
    • 2010
  • The interfacial adhesion strengths between screen-printed Ag film and epoxy resin-coated polyimide were evaluated by $180^{\circ}$ peel test method. Measured peel strength value was initially around $164.0{\pm}24.4J/m^2$, while the heat treatment during 24h at $120^{\circ}C$ increase peel strength up to $220.8{\pm}19.2J/m^2$. $85^{\circ}C/85%$ RH temperature/humidity treatment decrease peel strength to $84.1{\pm}50.8J/m^2$, which seems to be attributed to hydrolysis bonding reaction mechanism between metal and adhesive epoxy resin coating layer.

Time-Based Characteristics of Acoustic Emission During Dental Composite Restoration (치아 와동의 복합레진 수복시 음향방출의 시간적 발생 특성)

  • Gu, Ja-Uk;Choi, Nak-Sam;Arakawa, Kazuo
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.35 no.2
    • /
    • pp.169-174
    • /
    • 2011
  • Acoustic emission (AE) signals were detected and analyzed in real time during the polymerization shrinkage of composite resin restoration in an artificial dental ring with a class I cavity. Most AE hit events were observed in the initial curing period of the 1st region with high contraction rate. The range of the $2^{nd}$ region for the stainless steel specimen was shorter than that for the PMMA specimen but longer than that for the human dentin specimen. AE hit events showed a blast-type signal having an amplitude in the range of 25.45 dB and a frequency band of 100.200 kHz or 240.300 kHz. These values of amplitude and frequency indicated the fracture of resin or of the adhesive layer.

A Study on Improvement of Adhesion HTPB Propellant/Liner/Insulation (HTPB계 추진제/라이너/내열재의 접착력 향상에 관한 연구)

  • Park, Sungjun;Song, Jongkwon;Park, Euiyong;Rho, Taeho;Choi, Sunghan
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.23 no.4
    • /
    • pp.92-97
    • /
    • 2019
  • A study was conducted to improve the adhesion of propellant, liner,and insulation. Insulation was shown to be more advantageous in improving the adhesion when a barrier coat was applied compared to a bare insulation layer. It was confirmed that the adhesion strength between the insulation and the propellant improves as the thickness of the liner coating increases. The liner was cured for 24 h. If the liner is cured for a long time, it will adversely affect adhesion. Adhesion is also improved when a bonding agent is applied. As the bonding agent content increases, the adhesion improves. There is a change in the adhesive strength depending on the type of bonding agent used. HX-868 shows slightly more improved adhesion than HX-752.

Fabrication of 3D Multilayered Microfluidic Channel Using Fluorinated Ethylene Propylene Nanoparticle Dispersion (불소화 에틸렌 프로필렌 나노 입자 분산액을 이용한 3차원 다층 미세유체 채널 제작)

  • Min, Kyoung-Ik
    • Korean Chemical Engineering Research
    • /
    • v.59 no.4
    • /
    • pp.639-643
    • /
    • 2021
  • In this study, fluorinated ethylene propylene (FEP) nanoparticle as an adhesive for fabricating a three-dimensional multilayered microfluidic device was studied. The formation of evenly distributed FEP nanoparticles layer with 3 ㎛ in thickness on substrates was achieved by simple spin coating of FEP dispersion solution at 1500 rpm for 30 s. It is confirmed that FEP nanoparticles transformed into a hydrophobic thin film after thermal treatment at 300 ℃ for 1 hour, and fabricated polyimide film-based microfluidic device using FEP nanoparticle was endured pressure up to 2250 psi. Finally, a three-dimensional multilayered microfluidic device composed of 16 microreactors, which are difficult to fabricate with conventional photolithography, was successfully realized by simple one-step alignment of FEP coated nine polyimide films. The developed three-dimensional multilayered microfluidic device has the potential to be a powerful tool such as high-throughput screening, mass production, parallelization, and large-scale microfluidic integration for various applications in chemistry and biology.

Studies on the Biological Behaviors of Taxol Derivatives (Taxol 유도체들의 생물학적 거동에 관한 연구)

  • Awh, Ok-Doo;Yoo, Dae-Wung;Im, Sang-Moo
    • The Korean Journal of Nuclear Medicine
    • /
    • v.31 no.4
    • /
    • pp.440-451
    • /
    • 1997
  • This study was designed to prospect the $^{111}In$-labelled paclitaxel as tumor imaging agent. In order to provide a taxol molecule with a functional group which is able to chelate In-111, taxol-DTPA conjugate and 2'-hemisuccinyltaxol were synthesized by esterification of taxol at C-2'on C-13 carbon with DTPA anhydride and succinic anhydride, respectively. Synthesis yield of the taxol derivatives was 34% for taxol-DTPA and 80% for 2'-hemisuccinyltaxol. Cytotoxicity of the taxol derivatives were measured by MTT method toward cell lines HT29, B16, P388, and CT26. The cytotoxic activities of the taxol derivatives were maintained, although less active than taxol. Radiolabelling of the taxol derivatives were proceeded directly with $^{111}InCl_3$ or indirectly with $^{111}In$-citrate(ligand-exchange method). The ligand-exchange method was not suitable because some precipitates appeared during the reaction. On the contrary, by direct radiolabelling method, we were able to obtain taxol-DTPA-$^{111}In$ in 100% radiochemical yield. However, 2'-hemisuccinyltaxol was not labelled by both methods. Yield and radiochemical purity of the radiolabelled com-pound were determined by HPLC, paper chromatography and instant thin layer chromatography. Taxol-DTPA-$^{111}In$ was characterized to be hydrophilic by lipophilicity test, and nearly non-adhesive to HT29, B16, P388, and CT26 by cell binding affinity test. Binding affinity of the taxol-DTPA-$^{111}In$ complex to serum proteins was also examined by protein precipitation with 30% trichloroacetic acid. The results showed that 30% of the taxol-DTPA-$^{111}In$ complex binds with serum proteins.

  • PDF

The Oogenesis of Chinese minnow, Leuciscinae, Teleostei (경골어류 황어아과 버들치의 난자형성과정)

  • Kim, Dong-Heui;Chang, Byung-Soo;Jung, Han-Suk;Teng, Yung-Chien;Kim, Seok;Lee, Kyu-Jae
    • Applied Microscopy
    • /
    • v.39 no.3
    • /
    • pp.237-243
    • /
    • 2009
  • Chinese minnow, Rhynchocypris oxycephalus is a teleost belonging to Leuciscinae, Cyprinidae. The oogenesis and ultrastructure of egg envelope in Chinese minnow were investigated by light and electron microscopes. The ovary was of white yellowish and ellipsoidal shape with the major axis 30 mm and the minor axis 7mm. Cytoplasm of oogonia was basophilic and many nucleoli were located at inside of nuclear membrane. In primary oocytes, yolk vesicles were distributed only in the marginal area and egg envelope was not formed on the outside of an egg. In secondary oocytes, the egg envelope was formed and yolk vesicles in the cytoplasm were increased than the earlier stage. The basophilic substance of cytoplasm was changed to acidic. In case of matured egg, thickness of egg envelope and size of egg were increased. The yolk vesicles were changed to yolk mass in accordance with development. The outer surface of egg envelope was covered by microvilli-structures, and had a micropyle on the area of animal pole. Egg envelope consisted with 2 layers, an adhesive outer layer with microvilli-structures and fibrillar inner layer. In conclusion, the oogenesis of Chinese minnow was characterized by the increase in cell size, the formation and accumulation of yolk, and the decrease of basophilic substance in the cytoplasm. The oogenesis of Chinese minnow seems to share common patterns in Cyprinidae, but these ultrastructural unique characters of egg envelope can be utilized in taxonomy of teleost.

The Study on Physical and Mechanical Properties of Composite Board, Using Byproduct of Plywood for Core Layer (합판 정재단 부산물을 중층 Core로 이용한 복합보드의 물리·기계적 성질에 관한 고찰)

  • Choe, Song-Kyu;Pi, Duck Won;Kang, Seog Goo
    • Journal of the Korean Wood Science and Technology
    • /
    • v.41 no.6
    • /
    • pp.490-496
    • /
    • 2013
  • The board using recycled wood waste chip tends to decrease in terms of physical and mechanical properties. The reasons are notably different shape of chips, components of used adhesive and impurity content, which bring the irregular quality and downgrading of board. More over, the board has higher emissivity of formaldehyde than regular board, because recycled chip contains adhesives that were used to make previous products. This low quality of products weakens the price and quality competitiveness, and it led to bringing the issue of problem in Korean board industry. For these reason, in this study, boards using byproducts of plywood were made to evaluate physical and mechanical properties according to manufacturing conditions. As a result, The board was consists of 4~16 mesh chips for core layer and veneer on both face and they were combined using EMDI, and its' bending strength was 57.7 $N/mm^2$ which is 215% higher than that of OSB (26.8 $N/mm^2$). Moreover, the emissivity of formaldehyde was 0.7 ppm, this board seems to substitute OSB for rated sheathing.

EFFECT OF CHLORHEXIDINE ON MICROTENSILE BOND STRENGTH OF DENTIN BONDING SYSTEMS (Chlorhexidine 처리가 상아질 접착제의 미세인장결합강도에 미치는 영향)

  • Oh, Eun-Hwa;Choi, Kyoung-Kyu;Kim, Jong-Ryul;Park, Sang-Jin
    • Restorative Dentistry and Endodontics
    • /
    • v.33 no.2
    • /
    • pp.148-161
    • /
    • 2008
  • The purpose of this study was to evaluate the effect of chlorhexidine (CHX) on microtensile bond strength (${\mu}TBS$) of dentin bonding systems. Dentin collagenolytic and gelatinolytic activities can be suppressed by protease inhibitors, indicating that MMPs (Matrix metalloproteinases) inhibition could be beneficial in the preservation of hybrid layers. Chlorhexidine (CHX) is known as an inhibitor of MMPs activity in vitro. The experiment was proceeded as follows: At first, flat occlusal surfaces were prepared on mid-coronal dentin of extracted third molars. GI (Glass Ionomer) group was treated with dentin conditioner, and then, applied with 2 % CHX. Both SM (Scotchbond Multipurpose) and SB (Single Bond) group were applied with CHX after acid-etched with 37% phosphoric acid. TS (Clearfil Tri-S) group was applied with CHX, and then, with adhesives. Hybrid composite Z-250 and resin-modified glass ionomer Fuji-II LC was built up on experimental dentin surfaces. Half of them were subjected to 10,000 thermocycle, while the others were tested immediately. With the resulting data, statistically two-way ANOVA was performed to assess the ${\mu}TBS$ before and after thermo cycling and the effect of CHX. All statistical tests were carried out at the 95 % level of confidence. The failure mode of the testing samples was observed under a scanning electron microscopy (SEM). Within limited results, the results of this study were as follows; 1. In all experimental groups applied with 2 % chlorhexidine, the microtensile bond strength increased, and thermo cycling decreased the micro tensile bond strength (P > 0.05). 2. Compared to the thermocycling groups without chlorhexidine, those with both thermocycling and chlorhexidine showed higher microtensile bond strength, and there was significant difference especially in GI and TS groups. 3. SEM analysis of failure mode distribution revealed the adhesive failure at hybrid layer in most of the specimen. and the shift of the failure site from bottom to top of the hybrid layer with chlorhexidine groups. 2 % chlorhexidine application after acid-etching proved to preserve the durability of the hybrid layer and microtensile bond strength of dentin bonding systems.

MORPHOLOGIC CHANGE OF DENTIN SURFACE ACCORDING TO THE DIFFERENCE IN CONCENTRATION AND APPLICATION TIME OF PHOSPHORIC ACID (인산용액의 농도 및 적용시간 차이에 따른 상아질 표면의 형태적 변화)

  • Kim, Myeong-Su;Ohn, Young-Seok;Lee, Kwang-Won;Son, Ho-Hyun
    • Restorative Dentistry and Endodontics
    • /
    • v.23 no.1
    • /
    • pp.141-161
    • /
    • 1998
  • The depth and patterns of demineralization according to the difference in concentration and application time of phosphoric acid were observed through the transmission electron microscope, and shear bond strengths to the acid -conditioned dentin were then measured and compared with the TEM results. To investigate the influence of polymer addition into the phosphoric acid and the effect of difference in concentration and application time of the acid, the specimens were randomly divided into 9 groups. Among the specimens, the exposed dentin surfaces were acid-conditioned with 10% polymer-thickened phosphoric acid(All Bond 2, Bisco, U.S.A.) and aqueous 10%, 20%, 30%, 40% phosphoric acid for 20 seconds, The rest of the specimens were acid-conditioned with 10% phosphoric acid for 15s, 30s, 60s, 120s respectively. The specimens were immersed in 4% glutaraldehyde in 0.1M sodium cacodylate buffer and postfixed with 1 % osmium tetroxide without decalcification and then observed under a JEOL Transmission Electron Microscope(JEM 1200 EX II, Japan). After the specimens were acid-conditioned as the above, primer and adhesive resin were applied to blot-dried dentin and shear bond strengths were then measured and analysed. The results were as follows : 1. The intertubular demineralization depth of 4.0-$5.0{\mu}m$ in 10% polymer-thickened phosphoric acid gels was similar or slightly deeper than that of 4.0-$4.5{\mu}m$ in aqueous 10% phosphoric acid solution. 2. The intertubular demineralization depth of aqueous 20%, 30% and 40% phosphoric acid solution was 6.5-$7.0{\mu}m$, 6.5-$7.5{\mu}m$ and 9.0-$15.0{\mu}m$ respectively. It showed that the depth of dentin demineralization is partly related to the concentration of phosphoric acid solution. 3. The intertubular demineralization depth of aqueous 10% phosphoric acid solution in application time for 15s, 30s, 60s and 120s was 2.5-$3.0{\mu}m$, 4.0-$6.0{\mu}m$, 6.5-$7.0{\mu}m$ and 8.5-$14.0{\mu}m$ respectively. It showed that the depth of dentin demineralization is directly related to the application time of phosphoric acid solution. 4. The partially demineralized dentin layer between demineralized collagen layer and unaffected dentin was showed to a width of 0.5-$1.0{\mu}m$ in lower concentration groups treated with aqueous 10% phosphoric acid for 20s, 60s, 120s and 20% phosphoric acid for 20s. 5. The demineralization effect at the border of intertubular-peritubular junction was less evident than that in the peritubular and intertubular dentin. The collagen fibers in the intertubular dentin had a random orientation, whereas those that lined the tubules were circumferentially aligned. The cross-linkage of dentinal collagen in demineralized collagen layer was clearly seen. 6. A statistically significant difference of bond strengths according to the difference in phosphoric acid concentration did not exist among the groups treated with 10%, 20%, 30% and 40% acid solution (P>0.05). However, bond strengths to the treated dentin with 10% phosphoric acid solution for 30s were significantly higher than that for 120s (P<0.05).

  • PDF

THE STUDY ON THE MICROLEAKAGE PATTERN OF FLOWABLE COMPOSITE RESIN RESTORATIONS ACCORDING TO THE TYPE OF ADHESIVE MATERIALS (접착제에 따른 유동성 복합 레진 수복물의 미세누출 양상에 관한 연구)

  • Park, Ji-Eun;Kim, Jong-Soo;Yoo, Seung-Hoon
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.35 no.3
    • /
    • pp.456-468
    • /
    • 2008
  • This study was performed to evaluate the quality of newly offered dentin bonding system($AdheSE^{(R)}$ One) by comparing the degree of microleakage measured with those of several conventional adhesive materials(AQ Bond Plus and $Adper^{TM}$ Single Bond 2). The quality of hybrid layer and resin tags was analyzed by observing restoration/ tooth interface under SEM. All-in-one system is in the limelight for having advantage of reducing chair time of children with difficult behavior pattern. Therefore the possibility of clinical application of All-in-one system was evaluated. The results obtained are as follows; 1. At the enamel margin, group II(AQ Bond Plus) showed the highest value of microleakage, and the other groups showed decreased value in order of group III($AdheSE^{(R)}$ One) and I($Adper^{TM}$ Single Bond 2). There was statistically significant difference between group II and the others(p<0.05), and no statistical difference was found between group I and III. 2. At the dentin margin, microleakage value was increased in order of group II, I, III and significant difference between all groups(p<0.05). 3. In group I and III, microleakage value measured at the enamel margin was significantly lower than that seen at the dentin margin(p<0.05), and there was no statistical difference in group II. 4. Resin tags observed under SEM were very weak and tangled in group II and III while the strong and thick tags were observed in group I. In conclusion, careful case selection and accurate clinical application is recommended in using AQ Bond Plus and $AdheSE^{(R)}$ One, giving consideration of the results showing its higher microleakage and weaker strength than $Adper^{TM}$ Single Bond 2.

  • PDF