• Polymer(Korea)
• /
• v.29 no.1
• /
• pp.96-101
• /
• 2005

Fluoropolymer of PTFE and PFA etc. is a heat resistance polymeric material that it is known as that maximum continuous use temperature reaches for 260 $^{\circ}C$. It was observed that these polymers had the enough thermal stability so enough that it was kept by thermal aging of 280 $^{\circ}C$/7 weeks too in this study. However, such thermal stability means that bulk material property is kept such as mechanical strength, melting point and initial pyrolysis temperature etc. If these polymers are evaluate by coating property such as surface contact angle, surface morphology, surface scratch, thing that heat resistance is not enough was confirmed in this study. Thermal aging of flouropolymer coating was achieved by gear aging oven that the exchange rate of air was controlled, and the analysis results were indicating serious damage of surface morphology and adhesive strength on metal substrate.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.11a
• /
• pp.191-192
• /
• 2022

It was intended to evaluate whether the primer affects the physical performance of the waterproofing membrane coating. For this end, the physical performance change of the urethane waterproofing membrane coating was evaluated for urethane-based and polymer-based primers. As a result of the evaluation, it was confirmed that the type of primer may affect the physical performance of the waterproofing membrane coating. In particular, a difference in performance of more than 100% was confirmed in tensile strength and percentage elongation. Through these results, it was confirmed that the selection of the primer was important. In the future, follow-up studies on various waterproofing membrane coatings are needed.

• Journal of the Korea Concrete Institute
• /
• v.20 no.5
• /
• pp.635-642
• /
• 2008

In recent years, epoxy-coated reinforcing bars have been widely used in order to prevent the corrosion of ordinary reinforcing bar. However, they have a bad balance between performance and cost. Especially, they have a brittleness properties, low bond strength to cement concrete and no good bend-ability in the field. The purpose of this study is to evaluate the tensile properties and adhesion of hybrid-type anti-corrosion polymer cement slurry (PCS). PCSs are prepared with four types polymer dispersions using fly ash and silica fume, and tested for proper coating thickness, tensile properties, adhesion to steel plate and bend-ability. From the test results, the viscosity of PCS is effected by polymer dispersion types, and is a little decreased by using fly ash. The coating thickness of PCS has a proper thickness at polymer-binder ratio of 100%. It is apparent that the coating thickness has various values according to viscosity of PCS, water-binder ratio and polymer-binder rato. PCS has a good various anticorrosion properties and physical properties such as tensile strength, adhesion and bend-ability. It is also recommended that proper coating thickness to reinforcing bar is in the ranges of 150 to $250{\mu}m$ for bond strength, adhesion and bend-ability. It is also expected that the coated reinforcing bar using PCS is widely used instead of epoxy coated reinforcing bar in the industrial field.

• Journal of Adhesion and Interface
• /
• v.20 no.4
• /
• pp.146-154
• /
• 2019

In this study, alkoxysilane-functionalized amphiphilic polymer (AFAP), which have hydrophilic segment and hydrophobic segment functionalized by alkoxysilane group at the same backbone, was synthesized and used as a dispersant and control agent for reaction rate in the preparation of colloidally stable organic-inorganic (O-I) hybrid sols. After reaction with fluorosilane compounds, fluorinated O-I hybrid sols were prepared and coated onto glass substrate to form hydrophobic O-I hybrid coating films through low-temperature curing process. Surface hardness and hydrophobicity of cured coating films were varied with type of solvent and composition of AFAP and fluorinated alkoxysilane compounds. At appropriate solvent and composition of fluorinated alkoxysilane compounds, O-I hybrid coating film having high transparency and surface hardness could be prepared, which could be applicable to cover window of solar cell and displays.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.22 no.6
• /
• pp.579-585
• /
• 2009

In this paper, a series of finite element analyzes were carried out to evaluate the performance of the RC beams strengthened with sprayed fiber reinforced polymer(SFRP) coating. A damage constitutive model based on the micromechanical constitutive model(Lee, 2001) in conjunction with the damage models(Lee 등, 2000) for SFRP coating was implemented into the finite element code ABAQUS. The present prediction results were compared with experimental data(Ha, 2007; Ha 등, 2009) to assess the accuracy of the damage constitutive model. It was concluded from the comparative study that the computational model developed by implementing the damage constitutive model into ABAQUS is suitable for the prediction of the performance of RC beams strengthened with SFRP coating.

• Journal of Industrial and Engineering Chemistry
• /
• v.68
• /
• pp.399-405
• /
• 2018

We report the fabrication of organic field-effect transistors (OFETs) via spray coating of electrochemically exfoliated graphene (EEG) and conducting polymer hybrid as electrodes. To reduce the roughness and sheet resistance of the EEG electrodes, subsequent coating of conducting polymer (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)) and acid treatment was performed. After that, active channel layer was developed by spin coating of semiconducting poly(3-hexylthiophene) on the hybrid electrodes to define the bottom gate bottom contact configuration. The OFET devices with the EEG/PEDOT:PSS hybrid electrodes showed a reasonable electrical performances (field effect mobility = $0.15cm^2V^{-1}\;s^{-1}$, on/off current ratio = $10^2$, and threshold voltage = -1.57V). Furthermore, the flexible OFET devices based on the Polydimethlsiloxane (PDMS) substrate and ion gel dielectric layer exhibited higher electrical performances (field effect mobility = $6.32cm^2V^{-1}\;s^{-1}$, on/off current ratio = $10^3$, and threshold voltage = -1.06V) and excellent electrical stability until 1000 cycles of bending test, which means that the hybrid electrode is applicable to various organic electronic devices, such as flexible OFETs, supercapacitors, organic sensors, and actuators.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.318-318
• /
• 2006

4-Vinylbenzyl maltohexaoside peracetate, 1, was copolymerized with divinylbenzene using the initiator for nitroxide-mediated living radical polymerization, 2, to afford the polystyrene microgel with acetyl maltohexaose, 3. The deacetylation of 3 was achieved by treatment with sodium methoxide in dry 1,4-dioxane to produce the polystyrene microgel with maltohexaose, 4. A good coating property of the polystyrene microgel was combined with an excellent hydrophilic property derived from maltohexaose. In addition, 4 showed the ability to solubilize fullerene in aqueous solution. Therefore, 4 has a potential application as a special coating using functional but incompatible compounds such as fullerene on the surface of various hydrophilic materials.

• Corrosion Science and Technology
• /
• v.16 no.3
• /
• pp.151-159
• /
• 2017

The MA8 alloy (formula Mg-Mn-Се) has been shown to have greater corrosion stability than the VMD10 magnesium alloy (formula Mg-Zn-Zr-Y) in chloride-containing solutions by Scanning Vibrating Electrode Technique (SVET) and by optical microscopy, gravimetry, and volumetry. It has been established that the crucial factor for the corrosion activity of these samples is the occurrence of microgalvanic coupling at the sample surface. The peculiarities of the kinetics and mechanism of the corrosion in the local heterogeneous regions of the magnesium alloy surface were investigated by localized electrochemical techniques. The stages of the corrosion process in artificial defects in the coating obtained by plasma electrolytic oxidation (PEO) at the surface of the MA8 magnesium alloy were also studied. The analysis of the experimental data enabled us to determine that the corrosion process in the defect zone develops predominantly at the magnesium/coating interface. Based on the measurements of the corrosion rate of the samples with PEO and composite polymer-containing coatings, the best anticorrosion properties were displayed by the composite polymer-containing coatings.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.991-994
• /
• 2003

In this study, we have investigated a process of preparation of white and black pigment particles by physical or chemical coating with functionalized polymers for the flexible low-cost paper-like display. This polymer coating provided <1 ${\mu}m$ monodispersed particles changed their dispersion, density, optical and electrical properties.

• Carbon letters
• /
• v.4 no.1
• /
• pp.24-30
• /
• 2003

In this study, densified 4D carbon/carbon composites were made from carbon fiber and coal tar pitch through the process of pressure impregnation and carbonization and then followed by carbonization and graphitization. To improve the oxidative resistance of the prepared carbon/carbon composites, the surface of carbon/carbon composites was coated on SiC by the pack cementation method. The SiC coated layer was created by depending on the constitution of pack powder, and reaction time of pack-cementation. The morpology of crystalline and texture of these SiC coated carbon/carbon composites were investigated by XRD, SEM/EDS observation. So the coating mechanism of pack-cementation process was proposed. The oxidative res istance were observed through the air oxidation test, and then the optimal condition of pack cementation was found by them. Besides, the oxidative mechanism of SiC formed was proposed through the observation of SiC coated surface, which was undergone by oxidation test.