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사우라바바타라이,이성일,이연식 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Waterborne polyurethane (WPU) coating films with low gloss can be prepared using additives (e.g., matting agents such as silica). However, the matting agents tend to disperse imperfectly due to the incompatibility between the additives and WPU dispersion, leading to inhomogeneity of gloss. Furthermore, the gloss increases due to disappearance of the agents after a period of use. In this study, a series of WPU dispersions were synthesized using diols with different molecular weights via prepolymer emulsification process. The resulting polymer films were characterized with respect to surface morphology, thermal behavior, light transmittance, water absorption, tensile strength, gloss, etc. The synthesis and characterization of WPU coating films will be presented in detail.
Effects of Polyols for the Preparation of Low Gloss Waterborne Polyurethane Coating
사우라바바타라이,이성일,이연식 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
In order to obtain polyurethane (PU) with low gloss, people employed PU with rough surface roughness by introducing additives such as silica. The matting agents when added to the WPU dispersion tend to disperse imperfectly due to the incompatibility between the additive and WPU dispersion, leading to inhomogeneity of gloss in the surface of substrates. Furthermore, the gloss increases due to disappearance of the agents after a period of time use. Nowadays, single component waterborne PU (WPU) is a trend in field of coating industry. In this research, a series of WPU were synthesized under different conditions (e.g., different contents of polyols and DMPA, etc.) via prepolymer emulsification process. FTIR was used to confirm the chemical structures. The rough surface morphology, particle size distribution, phase separation behavior along with their hardness, adhesion capacities and thermal stabilities were also studied. All the experimental data and results will be presented in detail.
Preparation of polyaniline coated polystyrene beads for adsorption of silver ions as nanoparticles
사우라바바타라이,허공달,이연식 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1
In this study, cross-linked polystyrene beads were synthesized by conventional free-radical suspension polymerization, and the resulting beads were subsequently coated by polyaniline via polymerization of aniline. Sieved polymer beads with outer diameter in the range of 0.5- 0.8 mm were used for the further study. The surface morphologies of the polymer beads before and after the coating were studied by SEM and TEM. The adsorption efficiency of the polymer beads toward silver ion as nanoparticles was studied at various different conditions: temperature, pH, concentration of silver ion, and contact time. The experimental results will be presented in details.
Preparation of polyaniline -coated polystyrene beads for sorption of silver ions
사우라바바타라이,이연식 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
The rapid increase in the application of metals in different industries has led to serious water and environment pollutions. The trace of metal ions in water has caused adverse effects to human beings as well as animals and plants. Silver is one of the metals which have been most abundantly used and also wasted in many different ways. We have attempted to prepare nano-sized polyaniline-coated polystyrene (PAN/PS) beads via emulsion polymerization. According to their FE-SEM images, the average diameter is ~250 nm and the surface appears very rough. The adsorption behaviors of the polymer particles were studied at various pH values, concentrations and time intervals. The core/shell type polymer beads having .NH- groups on their surface exhibited high adsorption and redox capacity up to more than 95% removal toward silver ions in an aqueous phase. The reduction of silver ions to silver particles was confirmed by XRD data. Based on our current experimental results, the PAN/PS nanoparticles seem to be very useful sorbents toward silver ions, due to their low cost, reusability, and high adsorption capacity.