• Fibers and Polymers
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• v.1 no.1
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• pp.6-11
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• 2000

In the polycondensation reaction of polyethyleneterephthalate(PET), $Sb_2$$O_3$, can react effectively as a catalyst, if physically transformed. $Sb_2$$O_3$ powder is transformed into liquid solution by dissolving in ethylene glycol(EG). Homogeneous catalyst is made by mixing this liquid solution with glycols having different solubility. The efficient reaction of PET polymerization is expected by using homogeneous catalyst. PET was synthesized using homogeneous catalysts of 4 wt.% $Sb_2$$O_3$ solution dissolved in glycol[EG, 2,2-bis(4-(2-hydroxyethoxy)phenol)propane(BHPP), neopentyl glycol(NPO), and 1,3-propandiol(PD)]. PET using EG-BHPP($Sb_2$$O_3$) catalysts shows the highest I.V. within a reaction time of 120 min. In the p-d analysis, PET using EG-BHPP($Sb_2$$O_3$) catalysts has the fastest propagation rate and slowest degradation rate. EG-BHPP($Sb_2$$O_3$) catalysts are more efficient than EG($Sb_2$$O_3$) catalysts and $Sb_2$$O_3$ powder catalysts.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.313-320
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• 1994

Rosin-maleic anhydride adduct(RMA) was synthesized from rosin and maleic anhydride. Highly purified RMA for the application of polymerization monomer was synthesized by means of two methods; the melt reaction followed by further purification and the solution reaction. As a result of this study, the solution reaction was better than the melt reaction for obtaining higher yield of RMA. Maximum yield of RMA obtained by the melt reaction was only 40%. But the yield of RMA obtained by the reaction in carbon tetrachloride solution was 48%(theoretical yield 87.6%) and that obtained by the reaction in acetic acid solution was 51.5%(theoretical yield 94%) respectively.

• Polymer(Korea)
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• v.35 no.5
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• pp.431-437
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• 2011

A polymeric coating solution based on poly(acryloyl diphosphoric acid)(poly(ADP)) was prepared via a radical polymerization of acryloyl diphosphoric acid using ammonium persulfate (APS) as an initiator in water at 70 $^{\circ}C$. The prepared polymeric coating solution exhibited significant antibacterial activity against salmonella typhimurium, pseudomonas aeruginosa, escherichia coli, and staphylococcus aureus. It also exhibited good antifungal activity against Asperigillus niger and good antiviral activity against the influenza (H1N1) virus. Additionally, it exhibited good flame retardant efficiency after applying it as a coating to a cotton fabric.

• Elastomers and Composites
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• v.14 no.1
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• pp.7-12
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• 1979

Graft copolymerization of methlymethacrylate(MMA) onto sodium alginate(SA) aqueous solution by sodium metaperiodate$(NaIO_4)$ as an initiator was carried out with the variation of the reaction time, the reaction temperature and the concentrations of initiator and monomer. The results obtained were as follows: 1. SA was easily separated from the reaction mixture of homopolymer, graft polymer and sodium alginate ungrafted by the treatment of concentrated boiling $Na_3PO_4$, solution with the small amount of $Na_2SO_3$ to the mixture and then isolated as the acid form by acidifying the salts solution containing SA. 2. The amount of graft polymer was larger than that of homopolymer below $70^{\circ}C$ whereas above $70^{\circ}C$ the amount of homopolymer was larger. 3. The sum of each amount of graft polymer ana homopolymer was always increased with increase of the reaction time, the reaction temperature and the concentrations of initiator and monomer. 4. With increase of the concentration of initiator, the graft efficiency was increased below $70^{\circ}C$ while decreased above $70^{\circ}C$. 5. Graft copolymerization of MMA onto SA in aqueous solution was carried out without initiator.

• Polymer(Korea)
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• v.30 no.1
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• pp.28-34
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• 2006

A series of methoxypoly(ethylene glycol) $(MPEG)-poly(\varepsilon-co-L-lactide)$ (PCLA) diblock copolymers were synthesized by ring-opening polymerization of a mixture of $\varepsilon-caprolactone$ and L-lactide with different ratios in the presence of $Sn(Oct)_2$. The characterization of MPEG-PCLA diblock copolymers were examined by $^1H-NMR$, GPC, DSC, and XRD. Kinetic study on ring-opening polymerization of monomer mixtures was carried out in various conditions such as a variation with polymerization time, amount of catalyst, and temperature. The highest conversion obtained in 1.2 ratic of initiator venn catalyst at $110\;^{\circ}C$. The biodegradable characterization of MPEG-PCLA diblock copolymers in aqueous solution was carried out by using GPC for $1\~14$ weeks. The biodegradability of MPEG-PCLA diblock copolymers increased as the L-lactide content of diblock copolymers increased. In conclusion, we confirmed the dependence of polymerization rate according to various conditions. In addition, we can control the biodegradability of MPEC-PCLA diblock copolymers by changing the ratio of PCL and PLA block segment.

• Elastomers and Composites
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• v.38 no.4
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• pp.303-315
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• 2003

Inorganic/organic composite particles were also synthesized by changing an initiator an it's concentration, concentration of an adsorbed surfactant, reaction temperature, and agitation speed in the presence of $CaCO_3$ adsorbed SDBS. The polymerization conditions were optimized according to the conversion of the core-shell composite particles. In the inorganic/organic core-shell composite particle polymerization, $CaCO_3$ absorbed surfactant SDBS of 0.5 wt % was prepared first and then core $CaCO_3$ was encapsulated by sequential emulsion polymerization using MMA, concentration of APS $3.16{\times}10^{-3}mol/L$ to minimize the formation of new PMMA particle during MMA shell polymerization. The structure characterization of the inorganic/organic core-shell particles was verified by measuring the decomposition degree of $CaCO_3$ using HCl solution. It was found that $CaCO_3$ was encapsulated by shell PMMA due to having excellent dispersion in the epoxy resin, smooth surface distinctly from spindle shape, and broad particle distribution after the capsulation.

• Membrane Journal
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• v.20 no.3
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• pp.259-266
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• 2010

Porous poly(propylene) supported gel polymer electrolytes (GPE) were synthesized by thermal polymerization of DEGDMA [Di(ethylene glycol) dimethacrylate] in electrolyte solutions (1 M solution of $LiPF_6$ in EC/DEC 1 : 1 mixture) at $70^{\circ}C$. AC impedance spectroscopy and cyclic voltammetry were used to evaluate its ionic conductivity and electrochemical stability window of the GPE membranes. Lithium ion battery (LIB) cells were also fabricated with $LiNi_{0.8}Co_{0.2}O_2$/graphite and GPE membranes via thermal polymerization process. Through the thermal polymerization, self sustaining GPE membranes with sufficient ionic conductivities (over $10^{-3}\;S/cm$) and electrochemical stabilities. The LIB cell with 5% monomer showed the best rate-capability and cycleability.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.4
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• pp.340-345
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• 2003

In order to choose the manufacturing method for extracting alginates from sea tangle, Laminaria japonica, three methods were applied. In Method I, alginates were extracted with NaOH solution from sea tangle powder and extracted alginates were precipitated and converted to alginic acid by $CaCl_2$ and HCI solution. Then alginic acid was converted to sodium alginates with $Na_2CO_3$ solution. Sodium alginates were precipitated with methyl alcohol and were resolved with hot water and this step was repeated three times. Method II was same to Method I except final step including that sodium alginates were precipitated and washed with methyl alcohol three times. Method III included that sodium alginates were extracted with $Na_2CO_3$ solution from sea tangle powder then sodium alginates were precipitated and washed with methyl alcohol three time. Extracting time increased with Increasing extracted alginates amounts but increasing rates were below $0.4\%/h.$ Alginates amounts recovered by Method III showed above 2 times more to those by Method I and II. Extracting time increased with increasing ash amount of sodium alginates but increasing rates were below $0.1\%/h.$ and that of sodium alginates extracted by Method III showed higher value $(5\%)$ than those by Method I and II. In the sodium alginates prepared by Method III, the amount of ash in alginates dried by air was $34.4\%,$ that by vacuum freeze drying was $47.8\%.$ Extracting time increased with decreasing average molecular weight (MW) and degree of polymerization (DP) of sodium alginates, MW and DP of alginates prepared by Method III were higher than those by Method I and II In same extracting time. Extracting time increased with decreasing rate of apparent viscosity change (SAV) of alginates solution, and SAV of alginates prepared by Method III showed higher value than those by Method I and II in same extracting time. SAV of alginates dried by air was higher than that by vacuum freeze drying. Relating equation among SAV MW and DP were MW = 60.066 (SAV) -93.950, DP =309.760 (SAV) -485.084 and MW = 0.914 (DP)+0.213.

• Journal of the Korean Chemical Society
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• v.19 no.4
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• pp.225-232
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• 1975

The elution behaviour of molybdate and tungstate through anion exchange column has been studied at the various pH. A discussion is made to evaluate the equilibrium constants of the polymerization of these acids comparing with the behaviour of chromate ion and dichromate ion. The eqailibrium constants found at $20^{\circ}$ are $K = 4{\times}10^{53} for 7MoO_4^{2-} + 8H^+ {\longleftrightarrow} Mo7O_{24}^{6- }+ 4H_2O$$ K = 3{\times}10^{54} for 6WO_4^{2-} + 7H^+ {\longleftrightarrow} HW6O_{21}^{5-} + 7H_2O$ referring to this results the conditions of separation of tungstate and molybdate are obtained. iThe quantitative separations of carbonate, molybdate and tungstate from the pregnant solution have been established by anion exchange chromatography, using the $22 cm{\times}44.27 cm^2$ column of Rexyn 201. The optimum eluents for the quantitative separation of those ions are as follows; 0.2M solution of sodium chloride at pH 8 for carbonate, the mixture of 0.5 M ammonium chloride and 0.05 M sodium sulfate at pH 5 for molybdate and 0.5 M solution of ammonium chloride at pH 10 for tungstate. Tungstate is directly recovered from the pregnant solution as a form of ammonium paratungstate, by eluting with ammonium chloride solution.

• Membrane Journal
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• v.24 no.1
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• pp.69-77
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• 2014

To prepare the hollow fiber nanofiltration composite membranes, the poly(vinylidene fluoride) (PVDF) membrane was hydrophilized with $K_2Cr_2OH$ and $KMnO_4$ aqueous solutions. And then the composite membrane was synthesized on that membrane surfaces using interfacial polymerization with piperazine (PIP) and trimesoyl chloride (TMC). The resulting membranes were characterized in terms of the rejection and flux for NaCl, $CaSO_4$, $MgCl_2$ 100 ppm solution and 300 ppm of NaCl and $CaSO_4$ mixed solution by varying the coating time, drying time, and the concentration of the coating materials. As a result, the higher rejections were shown for $K_2Cr_2OH$ solutionas a hydrophilization material, and the flux was enhanced while the rejection reduced as the hydrophilization time is longer. Also, the rejection increased and the flux reduced as the concentrations of triethyl amine (TEA) and sodium lauryl sulfate (SLS) were higher. Typically, the rejection 50% and flux 40 LMH for NaCl 100 ppm solution, and the rejection 55% and flux 48 LMH for $CaSO_4$ 100 ppm solution were obtained for the PVDF hollow fiber composite membrane prepared with the conditions of PIP 2 wt% (Triethyl amine (TEA) 7 wt%, SLS 20 wt% mixed solution against PIP concentration) and TMC 0.1 wt%.