• Macromolecular Research
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• v.11 no.6
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• pp.437-443
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• 2003

A series of alternating and alternating block copolycarbonates containing the constituent groups of polysulfone was synthesized through a multi-step solution condensation method. For the regulation of block length, monodisperse oligomers were prepared by using a large excess of the bisphenols and were subsequently incorporated into the copolymer chains. Separating the unreacted bisphenols from the oligomers by dissolution/precipitation steps took advantage of solubility differences. The structures of the monomers, oligomers, and copolymers were characterized and confirmed by GPC, NMR spectroscopy, mass spectrometry, and elemental analysis. Monodispersity of the oligomers, which is critical for control over the block length in the copolymers, was confirmed by GPC and mass spectrometry. Of the two constituent groups of the polysulfone, the sulfone linkage stiffens the polycarbonate copolymer chain, while the ether linkage softens it.

• Journal of the Korean Magnetic Resonance Society
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• v.5 no.1
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• pp.19-28
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• 2001

Miscibility and morphology in blends of bisphenol-A type polycarbonate and poly (ester-ether) elastomer with different compositions are studied by solid-state NMR spectroscopy. $^{13}$ C Solid-state NMR of CP/MAS/TOSS/DD, CP/MAS/DD, inversion recovery CP/MAS/DD, and 2D rotor driven spin diffusion techniques are used to identify the miscibility, morphology, and transesterification in blends. The blends of PC /BT elastomer with 15% to 42% of soft segment seem to be single phase miscible mixing and those of PC/PBT and PC/PBT elastomer with 62% of soft segment are cocontinuous two phase immiscible mixing. No significant transesterification reactions are observed in blends with different compositions.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.220-220
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• 2006

Rheological and electrical properties of the polycarbonate (PC) / multi-walled carbon nanotube (MWNT) were studied. The MWNT was funtoinalized by treating with the hydrogen peroxide ($H_{2}O_{2}$). The electrical conductivity showed higher value for the PC/MWNT ($H_{2}O_{2}$ treated, freeze drying) composites compared that of the PC/MWNT ($H_{2}O_{2}$ treated, thermal drying) composites. From the results of the morphological, rheological, and electrical properties of the PC/MWNT composites, it is suggested that the electrical and rheological properties of the PC/MWNT composites are affected by the MWNT-MWNT network structure which is related with the MWNT morphologies such as the degree of aggregation and aspect ratio of the MWNT.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.213-213
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• 2006

High molecular weight of polycarbonate(PC) and well dispersed PC/MMT nanocomposites were successfully prepared through the novel technology, microwave solid-state polymerization. In our studies, the microwave irradiation is more effective than conventional oil-bath heating on achieving the high molecular weight and uniform nanocomposites. Using the polycarbonate prepolymer made it possible to intercalate the short chains into the galleries of MMT more easily. And it was observed that prepared nanocomposites by microwave solid-state polymerization have more uniform dispersion of silicate of MMT into the polymer matrix than by oil heating.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.364-364
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• 2006

The rheological properties of Parmax 1200, a new semi-flexible substituted polyphenylene, were investigated. The reported high stiffness of the material was confirmed. The rheological measurements proved that, despite the very high stiffness of the molecules, Parmax showed shear thinning and that, although the viscosity is very high and the melt is highly elastic, the polymer can be extruded in the melt. A worm-like morphology was detected in AFM and TEM. This morphology could explain the reported mechanical and rheological behaviour. The compatibility with flexible chain polymers (e.g. polycarbonate) could also be explained by the worm-like morphology.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.3
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• pp.165-171
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• 2000

Experiments were carried out to measure variations in the oxidation potential and current density using the polarization curves of polycarbonate. The results were then examined to identify the influences affecting the oxidation potential related to various conditions, such as temperature, pH, and oxydase(citrate and lipase). The lines representing the active anodic and cathodic dissolution shifted only slightly in the potential direction relative to temperature, pH, and the effect of the enzyme. The Tafel slope for the anodic and cathodic dissolution was determined such that the reversibility polarization was indicated as being effected by various conditions. The slope of the polarization curves describing the active-to-passive transition region shifted noticeably in their direction. Also, by varying the conditions, the optimum conditions for the most ready transform were identified, including temperature, pH, oxidation rate, and resistance of oxidation potential. The critical oxidation sensitivity(I(sub)r/I(sub)f) of the anodic current density peak and maximum passive current density was also determined, which is used in measuring the critical corrosion sensitivity of a polycarbonate.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.100.3-100
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• 2001

This article deals with the development of a mathematical model for the finishing polycarbonate polymerization process using a horizontal rotating disk-ring reactor with counter-current gas sweeping and the performance analysis of the reactor system by using the model. Here we intend to propose a model describing the reactor system consisting of two phases, in which by-product phenol is removed from the polymer of high molecular weight compatible with the products of commercial grades. The vapor phase is represented by a tanks-ln-series model while the polymer melt phase is regarded as a plug flow reactor.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.3 s.108
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• pp.247-254
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• 2006

This paper (Part II) provides the application results of the method presented in a companion paper (Part I) where the dynamic equation for rotating polar orthotropic disk is formulated and its solution method is considered. The natural frequencies and critical speed of polycarbonate CD are calculated to validate the present method and are shown to by very accurate. The critical speeds of typical GFRP and CFRP CD's are computed by aligning the fibers in radial and circumferential directions. The radially reinforced CFRP CD is shown to have the five times higher critical speed than that of the polycarbonate CD. The natural frequencies and critical speeds of disks with various elastic modulus ratios are obtained. The results show that the radially reinforced disk is more effective in increasing critical speed than the circumferentially reinforced disk.

• Journal of Ocean Engineering and Technology
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• v.10 no.4
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• pp.51-57
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• 1996

A standard method for the evalution of the fracture toughness of the high polymer materials has not been fully developed in comparison with that for metallic materials, and has not yet established. In this paper, fracture toughness tests using polycarbonate specimens were carried out. The fracture thughness tests using polycabonate specimens were carried out. The fracture toughness of commercial polycarbonate were dependent on the specimen thickness. The specimen thickness is necessary above 8mm to obtain the valid $K_{IC}$. A cumulative counts were slightly dependent on specimen thickness.

• Macromolecular Research
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• v.14 no.6
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• pp.603-609
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• 2006

Tricyanopyrrolidene chromophores were prepared in order to compare their macroscopic nonlinear optical (NLO) properties with a conjugated structure through the long molecular axis. A thiophene or phenyl ring was tethered to an ethylenic bond; it may act as a lateral moiety to disrupt the planarity of a chromophore and lessen the electrostatic interaction. Thin film composites of these chromophores dissolved in amorphous polycarbonate (APC) were fabricated. Real time pole and probe method was employed to investigate the change of electro-optic (EO) signal during poling. The EO properties and their relaxation behaviors of the guest-host systems containing newly synthesized chromophores were investigated in detail.