Myung Jun Moon

Synthesis and properties of semifluorinated block copolymers containing poly(ethylene oxide) and poly(fluorooctyl methacrylates) via atom transfer radical polymerisation

Abstract Amphiphilic block copolymers of poly(ethylene oxide) (PEO) and poly(fluorooctyl methacrylates) were synthesised by atom transfer radical polymerisation of semifluorinated methacrylates such as 1H,1H-perfluorooctyl methacrylate, and 1H,1H,2H,2H-perfluorooctyl methacrylate using PEO macroinitiators. The use of mono- and difunctional initiator led to AB and ABA block copolymers with controlled molecular weights. The linear time dependence of ln([M]0/[M]) is consistent with a controlled polymerisation i.e. first-order in monomer concentration. Various block copolymers could be prepared by varying the ratio of monomer to macro-initiator. The copolymers self-assembled in chloroform to form micelles, which was evidenced by dynamic light scattering and transmission electron microscopy. Different morphologies of spheres and rods were observed by changing the copolymer composition. In addition, these surfactants lower the interfacial tension between water and supercritical carbon dioxide to stabilise water-in-carbon dioxide emulsions.

Raney Ni catalysts derived from different alloy precursors Part II. CO and CO2 methanation activity

Catalytic activity, in conjunction with reaction mechanism, was studied in the methanation of CO and CO2 on three Raney Ni catalysts derived from different Ni-Al alloys using different leaching conditions. Main products were CH4 and CO2 in CO methanation, and CH4 and CO in CO2 methanation. Any other hydrocarbon products were not observed. Over all catalysts, CO methanation showed lower selectivity to methane and higher activation energy than CO2 methanation. The catalyst derived from alloy having higher Ni content using more severe leaching conditions, namely higher reaction temperature and longer extraction time, showed higher specific activity and higher selectivity to methane both in CO and CO2 methanation. In CO and CO2 methanation on Raney Ni catalyst, catalytic activity was seen to have close relation with the activity to dissociate CO

Preparation of Silica/Poly(divinylbenzene) Composite Particles by Dispersion Polymerization in Supercritical Carbon Dioxide

Silica/poly(divinylbenzene) (PDVB) composite particles were synthesized by the dispersion polymerization of divinylbenzene (DVB) with ultrafine silica particles in supercritical carbon dioxide (scCO2). Silica particles of average diameter 130 nm were pretreated with 3-(trimethoxysilyl) propyl methacrylate in order to be well dispersed in CO2 and participated in the polymerization. Random copolymeric dispersant, poly(diisopropylaminoethyl methacrylate-co-heptafluorobutyl methacrylate) was used as a stabilizer to provide sufficient stabilization to latexes in scCO2 and the silica/PDVB composite powder was obtained in high yield from the polymerization. SEM analysis revealed that the composite particles prepared at 5% silica loading ratio and 6% stabilizer concentration with respect to monomer have the average diameter of 1.60 μm with uniform and spherical morphology. The composites were also characterized by FTIR spectroscopy and TGA.

Preparation of Mg(OH2/PMMA core-shell nanocomposite by emulsion polymerization

Nanosized magnesium hydroxide (Mg(OH) 2 ) was modified with 3-(trimethoxysilyl)propyl methacrylate (y-MPS) as silane coupling agent, and then core-shell nanocomposites of inorganic/organic pair were synthesized by the emulsion polymerization using methyl methacrylate (MMA) as the shell monomer. The compatibility of Mg(OH) 2 surface with MMA was highly improved through the condensation of γ-MPS. The structure of core-shell composite was examined by transmission electron microscope (TEM).

Synthesis and Photo-Polymerization of Poly(Alkyl Urethane) Acrylate Oligomers Using 2-Isocyanatoethyl Methacrylate for UV Curable Coating

The poly(alkyl urethane) acrylate oligomers (AUAOs) were obtained by the reaction of alkyl acrylate oligomers and 2-isocyanatoethyl acrylate. Synthesis of AUAOs were done with 2-mercaptoethanol (2-MEOH), alkyl (methyl, butyl, 2-ethylhexyl) acrylate, 2,2′-azobisisobutyronitrile (AIBN, initiator) and dibutyltin dilaurate as a catalyst. Then 2-MEOH was used for functional chain transfer agent. The oligomers were characterized by FT-IR, FT-NMR, rheometer, and DSC. Each oligomer was blended and photopolymerized by UV light, and their ball tack, adhesiveness, and thermal resistance were confirmed by ball tack tester and so on. Photo-polymerized AUAOs can be used for UV curable coatings, inks and adhesives.

Study on the Physical Properties by Combining Epoxy and Acryl Electrodeposition Paints

The important drawback of epoxy electrodeposition(ED) coatings is the lack of the weathering resistance caused by the structure of bisphenol A. To improve this yellowing phenomena, acryl ED coatings have been developed. Compared with the epoxy ED coatings, however, acryl ED coatings are relatively weak in the corrosion resistance and mechanical properties. The purpose of this study is complemented their drawbacks by mixing epoxy and acryl ED paints. The salt spray, accelerated weathering test(QUV) and cupping, bending, impact test were employed to investigate the corrosion resistance, weathering resistance, and mechanical properties of ED coatings. When the ratio of acryl to epoxy resin of ED coating is 0.33, the weathering resistances are appropriately improved in condition maintaining the corrosion resistance. It was shown that the weathering resistance for epoxy ED coating was adjusted by optimally mixing acryl ED paint.

Synthesis of Glycerol Carbonate from Biomass Glycerol: Focus on the Calcination Temperature

We carried out a reaction in which glycerol carbonate was synthesized by using glycerol and urea. The physical properties of the prepared catalysts were investigated by BET surface area, X-ray diffraction, temperature programmed desorption, and Field-emission scanning electron microcopy. In addition, we confirmed the conversion of the glycerol and the yield of the glycerol carbonate according to calcination temperature. From XRD results, the crystalline of prepared ZnAl2O4 was slowly increased with an increasing of the calcination temperature. When the calcination temperature of ZnAl2O4 was 500 , the conversion of the glycerol was 74.4% and the yield of the glycerol carbonate was 73.3%. The conversion of the glycerol and the yield of the glycerol carbonate can be obtained higher when acid/base ratio is approx. 1. From this result, we may conclude that the acid & base site density and ratio of catalysts were very important parameters in the synthesis of glycerol carbonate from urea and glycerol.

Synthesis And Characterization Of Polyurethane Acrylates For Uv Curable Coating Agents

The single hydroxyl-terminated urethane acrylate oligomers were synthesized from 2-mercaptoethanol (2-MEOH), alkyl (methyl, butyl, and 2-ethylhexyl) acrylate, and 2,2-azobisisobutyronitrile (AIBN, initiator), with dibutyltin dilaurate (DBTDL) as a catalyst. 2-MEOH was used as a functional chain transfer agent. Poly(alkyl urethane) acrylate oligomers were obtained by the reaction of single hydroxyl-terminated polyalkyl acrylates and 2-isocyanatoethyl acrylate. They were characterized by NMR, FT-IR spectroscopy, rheometer, and DSC. Because poly(alkyl urethane) acrylate oligomers have lower Tg and viscosity than hydroxyl-terminated polyalkyl acrylate oligomers (HTPAO) non-containing urethane groups, they can be used for ultraviolet (UV) curable coatings, inks, and adhesives.