• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.352-356
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• 2014

PDMS modified epoxy resin with epoxy group (EMPDMS) was prepared from the reaction of ${\alpha},{\omega}$-aminopropylpolydimethylsiloxane and diglycidyl ether of bisphenol-A (DGEBA) based epoxy resin, and PDMS modified epoxy hybrid compound (EMPDMSH) was prepared by introducing alkylesteraminopropyl alkoxy silane to EMPDMS. Their structures were characterized using FT-IR, $^1H$-NMR and $^{29}Si$-NMR. Coating materials were prepared by mixing EMPDMSH base and solvent. Physical properties of the coating materials coated on epoxy/glass fiber composite film were measured according to the content of PDMS in EMPDMSH. Contact angle of coating film was increased 30 to 71 degree. Adhesive property of coating film was 5B degree better then epoxy or acrylate coating materials, and surface roughness was decreased as increasing in EMPDMSH.

• BMB Reports
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• v.49 no.12
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• pp.655-661
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• 2016

Polymer brush is a soft material unit tethered covalently on the surface of scaffolds. It can induce functional and structural modification of a substrate's properties. Such surface coating approach has attracted special attentions in the fields of stem cell biology, tissue engineering, and regenerative medicine due to facile fabrication, usability of various polymers, extracellular matrix (ECM)-like structural features, and in vivo stability. Here, we summarized polymer brush-based grafting approaches comparing self-assembled monolayer (SAM)-based coating method, in addition to physico-chemical characterization techniques for surfaces such as wettability, stiffness/elasticity, roughness, and chemical composition that can affect cell adhesion, differentiation, and proliferation. We also reviewed recent advancements in cell biological applications of polymer brushes by focusing on stem cell differentiation and 3D supports/implants for tissue formation. Understanding cell behaviors on polymer brushes in the scale of nanometer length can contribute to systematic understandings of cellular responses at the interface of polymers and scaffolds and their simultaneous effects on cell behaviors for promising platform designs.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.343-348
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• 2000

The purpose of this study is to clarify properties adhesive strength of polymer-cement slurry for coated reinforcing bars. The epoxy coating material is superior to performance of anti-corrosion but lately age adhesive strength between concrete raise to structural problems. However, polymer dispersion with excellent performance of elasticity and adhesion can solve this problems. From the test results. adhesion of steel with polymer cement slurry using St/BA emulsion is show excellent without concerned coating thickness, and polymer cement slurry using St/BA emulsion is show adhesion in tension 1.2~2.2MPa at polymer cement ratio 50% of more.

• Elastomers and Composites
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• v.54 no.1
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• pp.30-34
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• 2019

Four different diisocyanates (IPDI; isophorone diisocyanate, HDI; hexamethylene diisocyanate, HMDI; dicyclohexylmethane-4,4'-diisocyanate, and XDI; m-xylylene diisocyanate) were used to prepare polyurethane gel-coats, and the weatherabilities, physical properties, and surface characteristics of the gel-coats were investigated with respect to the chemical structure of the diisocyanates. The weathering test results indicated that all of the diisocyanates used in this study were suitable for use in the preparation of the polyurethane gel-coat. However, the set-to-touch times and physical properties of the polyurethane gel-coat indicated that the cycloaliphatic diisocyanate (IPDI and HMDI) were ideal for the preparation of polyurethane gel-coats.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.807-810
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• 2005

In this study, MMA-modified paste of coating material for protecting the concrete structures was developed. The coating material was applied to cement concrete specimens by brush, roller and spray in each of which one, two and three layers to survey, by the cold-hot iterative test, the neutralization test, the chloride ion permeation test and the ante-abrasion test, the affect of painting methods and layers influencing on the durability of coating material. Results of the cold-hot iterative test showed that, regardless of the painting methods and layers, the defects such as crack or fuzz on surface were not produced. As the number of painting layers increased, the neutralization prevention as well as the chloride ion permeation prevention effects were increased. On the other hand, no difference was found between the painting methods. Reducing weight by abrasion of polymer paste coating material was $20\%$ comparing to that of cement mortar.

• Applied Chemistry for Engineering
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• v.33 no.6
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• pp.661-665
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• 2022

In this study, 2,5-dichlorobenzophenone was synthesized as a monomer using 1,4-dichlorbenzene, and subsequently, copolymers of benzoyl-p-phenylene and p-phenylene were prepared. The average molecular weight was improved using the low-molecular-weight polymer cutting method. The average molecular weight and glass transition temperature of the synthesized polymers were estimated. The as-prepared polymer was used as a hard coating material, and the coating was conducted on a poly(methyl methacrylate) plate. Furthermore, physical properties of the coatings, such as pencil hardness, adhesive strength, and abrasion resistance, were estimated. As the amount of p-phenylene in the copolymer increased, pencil hardness and abrasion resistance improved. The amount of p-phenylene in the copolymer can be increased to 30 mol% in order to increase the hardness of the coating, and the adhesive strength was insufficient for the copolymers with p-phenylene ratio greater than 35 mol%.

• Journal of Pharmaceutical Investigation
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• v.36 no.1
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• pp.11-17
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• 2006

The objective of this study was to confirm the effect of the type of dissolution media and paddle speed on nifedipine (ND) release profile from osmotic granule and the storage stability. Osmotic granule was manufactured by fluidized bed coating method. At each coating step, morphology of osmotic granule was differed. The size of osmotic granule was $750\;{\mu}m$ at 3 wt% membrane thickness. ND release was changed in diverse dissolution media, paddle speed. ND release is governed by not only osmotic pressure but diffusion from osmotic granule. ND release from osmotic granule decreased as storage period increased. These may be caused by liquid excipient which has low molecular weight. Storage stability of osmotic granule could be improved by removing liquid excipient from semipermeable membrane.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.13-22
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• 2006

Surface fog coating methods to porous pavements with a polymer, that contains MMA as a main ingredient, are being widely used in Japan and called 'Top-Coat Processes'. They have lots of effects such as to prevention of the pavement void choking, improvement of the water permeability of the pavements and so on. The purpose of this research is to show the characterization of the polymer to optimize the functions of the polymer fog-coat methods. This study focused on the difference of 'wetting' by water among polymers used for the fog coatings, and calculation the surface free energy from the water contact angle on each material. At the end, the water permeability test were conducted using porous asphalt mixtures that were coated with several kinds of polymers. The permeability was also measured on the specimens that were forcibly choked by muddy water and the resistance to choking was compared. It is concluded that the reduction of the surface free energy between water and a polymer improves the life of the permeability functions of porous pavements. Improvement of water permeation capacity and void-blocking controlling effects can be quantitatively evaluated using the interfacial tension ($\gamma$sl) with water for the coating material (high-viscosity asphalt and hardening resin binder). Consequently, the smaller the $\gamma$sl of the coating material the higher the water permeation capacity and void-blocking controlling effects of the porous asphalt pavements.

• Polymer(Korea)
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• v.38 no.6
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• pp.720-725
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• 2014

Aminopropyl terminated polydimethylsiloxane was synthesized by hydrosilylation reaction with hydride terminated polydimethlysiloxane and allyl amine. Polydimethylsiloxane modified urea with isocyanate group was prepared from cyclic trimer of hexamethyldiisocyanate with aminopropyl terminated polydimethylsiloxane. Polydimethylsiloxane modified urea/acrylate resin (PUA) was prepared from the urethane reaction of PU with isocyanate group and 2-hydroxyethylmethacrylate. PUA structure was analyzed by FTIR and NMR. Coating materials were prepared by mixing PUA, acrylic monomer, photo-initiator, and solvent and coated on PET film to obtain flexible hard coating film by UV irradiation.

• Polymer(Korea)
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• v.37 no.1
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• pp.22-27
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• 2013

In this study, we prepared separators with improved thermal stability by coating microporous polyethylene (PE) film for lithium secondary battery using poly(meta-phenylene isophthalamide) (Nomex). The mechanical and thermal properties of prepared separators were evaluated by thermal stability test and TMA as a function of the Nomex concentration and coating parameters. The corresponding coated PE separator showed better thermal and mechanical properties than the original PE separator. Electrochemical properties were also assessed by ionic conductivity, cyclic voltammetry and charge/discharge cycle.