• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.100-103
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• 2000

In the case of immobilizing of glucose oxidase into polypyrrole (PPy) using electrosynthesis, the glucose oxidase (GOx) forms a coordinate bond with the polymers backbone. However, because of intrinsic insulation and net-chain of the enzyme, the charge transfer and mass transport are obstructed during the film growth. Therefore, the film growth is dull. We synthesized the enzyme electrode by electropolymerization added some organic solvent. A formative seeds of film growth is delayed by adding ethanol. The delay is induced by radical transfer between ethanol and pyrrole monomer. The radical transfer shares the contribution of dopant between electrolyte anion and GOx polyanion. This may lead to increase amount of immobilized the enzyme in PPy. For the UV absorption spectra of synthetic solution before synthesis and after, in the case of ethanol added, the optical density was slightly decreased for the GOx peaks. It suggests amount of GOx in the solution was decreased and amount of GOx in the film was increased. We established qualitatively that amount of immobilization can be improved by adding a little ethanol in the synthetic solution. It is due to radical transfer reaction. The radical transfer shares the contribution of dopant between small and fast electrolyte anion and big and slow GOx polyanion.

• Macromolecular Research
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• v.15 no.1
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• pp.31-38
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• 2007

Pentamethylcyclopentadienyltitanium trichloride, bis(cyclopentadienyl)titanium dichloride ($Cp_2TiCl_2$), and bis(pentamethylcyclopentadienyl)titanium dichloride were used in the polymerization of styrene without the aid of Group I-III cocatalysts. The properties of the resulting polymer indicated that polymerization was more controlled than in thermal polymerization. The kinetic studies indicated that a lower level of termination is present and that the polymer chain can be extended by adding an additional monomer. To elucidate the mechanism of polymerization, a series of experiments was performed. All results supported the involvement of a radical mechanism in the polymerization using $Cp_2TiCl_2$. The possibility of atom transfer radical polymerization (ATRP) mechanism was investigated by isolating the intermediate species. We could confirm the activation step from the reaction of 1-PEC1 with $Cp_2TiCl$ by detecting the coupling product of the generated active radicals. However, the reversible deactivation reaction competes with other side reactions, and it detection was difficult with our model system.

• Journal of Adhesion and Interface
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• v.12 no.1
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• pp.1-10
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• 2011

An automated reaction calorimeter was used to directly monitor the rate of emulsion polymerization of vinyl acetate using poly(vinyl alcohol) (PVAs) having different degrees of blockiness. By using this technique in conjunction with other off-line measurements of the evolution of particle size distributions, important details of the process were observed. No constant graft rate period was observed for both low and high initial monomer-water ratios. The gel effect was observed for the low monomer-water ratio recipe. The particle size distributions were broad (particle diameter 40~100 nm) and bimodal. Continuous nucleation was observed to be accompanied by 'limited aggregation' and flocculation during the particle growth stages. It was speculated to be due to the occurrence of the extensive 'limited aggregation' and chain transfer to PVA leading to grafting.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.615-620
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• 2002

In the case of immobilizing of glucose oxidase into polypyrrole (PPy) using electrosynthesis, the glucose oxidise (GOx) forms a coordinate bond with the polymers backbone. However, because of intrinsic insulation and net-chain of the enzyme, the charge transfer and mass transport are obstructed during the film growth. Therefore, the film growth is dull. We synthesized enzyme electrodes by electropolymerization added some organic solvent, such as ethanol and tetrahydrofuran (THF). The formative seeds of film growth was delayed by adding ethanol. The delay was induced by radical transfer between ethanol and pyrrole monomer. The radical transfer reactions shared the contribution of dopants between electrolyte anion and GOx polyanion. This led to increase amount of immobilized the enzyme in PPy. For the UV absorption spectra of synthetic solution before synthesis and after, in the case of ethanol added, the optical density was slightly decreased for the GOx peaks. It suggests amount of GOx in the solution was decreased and amount of GOx in the film was increased.

• Textile Coloration and Finishing
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• v.4 no.3
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• pp.97-115
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• 1992

In order to improve the processability of rigid rod-like polyspiroacetals without significant loss of their good nature, in this work a few new ideas for molecular design were adopted: (1) Copolymerization for breaking the regularity of polymer repeating units. (2) Incorporation of flexible methylene linkages or spacers in rigid spiroacetal polymer main chain. (3) Derivatization of long flexible side chains onto rigid polymer backbone. On the basis of these ideas, a series of polyspiroacetals were prepared, using the phase transfer catalyst, BTMAC, by interfacial polymerization reactions of spiroacetal monomer (SAB) and disubstituted aromatic acid chlorides or aliphatic diacid chlorides. Physical properties of these polyspiroacetals are discussed in relation to their chemical structure and are compared with those of polyspiroacetals synthesized by several other researchers.

• Journal of the Korean Graphic Arts Communication Society
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• v.13 no.1
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• pp.1-12
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• 1995

Polymeric mesogens having a regularly alternating rigid-flexible repeating structure in the main-chain polymer exhibit distinct even-odd oscillation in their thermodynamic quantities with respect to the number of methylene units in the spacer. The even-odd oscillation depends on the number of methylene groups in the spacer the entropy change at the NI(nematic-isotropic) phase transition becomes less distinct when the linking group is replaced by the carbonate. In our previous work, we have suggested that the characteristics arise from the geometrical arrangement of the linkage. In this work, we have prepared a series of carbonate-type monomer and dimer liquid crystals. The thermodynamic behaviors at the NI phase transition have been compared with those previous reported for the ether- or ester-type liquid crystals. For the dimer series, the orientational order parameter of the mesogenic core was determined by using H-NMR technique. The origin of the difference observed among linking groups was found to the geometrical characteristics of chemical structure.

• Journal of the Korean Chemical Society
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• v.26 no.6
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• pp.421-426
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• 1982

Free radical-initiated copolymerization of diethyl isopropenyl phosphate (DEIPA) with vinyl acetate (VAc) and acrylonitrile (AN) was studied. The monomer reactivity ratios for the monomer pairs, determined at $60^{\cric}C$ using benzoyl peroxide as an initiator, are: ${\gamma}_1$(VAc) = 1.56, ${\gamma}_2$(DEIPA) = 0.44: ${\gamma}_1$(AN) = 15.2, ${\gamma}_2$(DEIPA) = 0.031. The values of the Alfrey-Price constants, Q and e, for DEIPA were calculated to be 0.015 and 0.39, respectively, from the VAc system, and 0.014 and 0.34, respectively, from AN/DEIPA pair. These results indicate that ${\alpha}$-methyl substituent of vinyl phosphate monomer decreases the general reactivity in free radical copolymerization. The intrinsic viscosity and number-average molecular weight of copolymers decreased as their content of DEIPA units increased, indicating a high degree of chain transfer caused by DEIPA, as previously learned in DEVPA system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.316-319
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• 2000

In the case of immobilizing of glucose oxidase into polypyrrole (PPy) using electrosynthesis, the glucose oxidase (GOx) forms a coordinate bond with the polymer's backbone. However, because of intrinsic insulation and net-chain of the enzyme, the charge transfer and mass transport are obstructed during the film growth. Therefore, the film growth is dull. We synthesized the enzyme electrode by electropolymerization added some organic solvent, A formative seeds of film growth is delayed by adding the solvent. The delay is induced by radical transfer between the solvent and pyrrole monomer. In the case of adding ethanol, the radical transfer shares the contribution of dopant between electrolyte anion and GOx polyanion. This may lead to increase amount of immobilized the enzyme in ppy. However, adding tetrahydrofuran (THF), the radical transfer is more brisk, resulting in short chained polymer. Therefore, the doping level is lowered and then amount of immobilized of enzyme is decreased. For the UV absorption spectra of synthetic solution before synthesis and after, in the case of ethanol added, the optical density was slightly decreased for the GOx peaks. It suggests amount of GOx in the solution was decreased and amount of GOx in the film was increased. We established qualitatively that amount of immobilization can be improved by adding a little ethanol in the synthetic solution. It is due to radical transfer reaction. The radical transfer shares the contribution of dopant between small and fast electrolyte anion and big and slow GOx polyanion.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.90-90
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• 2003

Living nature was appeared in the cationic polymerization of tort-butyl vinyl ether (TBVE), initiated by iodine, carried out in toluene at -78$^{\circ}C$. It was found that the number average molar mass of the resulting polymer (equation omitted) increases linearly as the conversion to polymer increase which reveals that there is no operation of chain transfer or termination process in this system. The polymers having narrow distribution and having molar mass of the resulting polymers are dependent on molar ratio of monomer and iodine.

• Polymer(Korea)
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• v.24 no.5
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• pp.646-655
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• 2000

Polymerizations of higher $\alpha$-olefins were carried out in toluene by using highly isospecific catalyst, rac-(EBI)M(NMe$_2$)$_2$ (EBI=1,2-ethylenebis-(1-indenyl); M=Zr(rac-1); M=Hf(rac-2)) In the presence of Al(i-Bu)$_3$/[Ph$_3$C][B($C_{6}F_{5}$)$_4$]. The polymerization of high $\alpha$-olefin showed high activity and similar polymerization behavior. The polymerization activity was affected by both monomer size and lateral size of polymer chain. The conversion of monomer to polymer decreases with the increased lateral size in the order of 1-pentene>1-hexene>1-octene>1-decene. The same dependences of melting behavior and intrinsic viscosity of polyolefin on lateral size were observed according to the results obtained by differential scanning calorimetry and intrinsic viscosity. All poly($\alpha$-olefin)s showed very high isotacticity (triad) and the isotacticity increases in the order of poly(1-pentene)$^1H$ NMR and Raman spectra analysis showed that chain transfer to cocatalyst, which generates saturated methyl groups, Is a main chain termination. The $\beta$-hydride eliminations, which generate unsaturated vinylidene, tri-substituted, and vinylene end group. are found to be minor chain terminations.