• Polymer(Korea)
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• v.24 no.1
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• pp.16-22
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• 2000

Poly(butylene terephthalate- co-oxybenzoate)(PBOT) containing mesogenic oxybenzoate units in the main chain was synthesized through ester exchange reaction by melt mixing of poly(butylene terephthalate)(PBT) and p-acetoxybenzoic acid (ABA). From the kinetics of the copolymerization reaction, the activation energies and the rate constants of homopolymerization and copolymerization, k$_{h}$ and k$_{c}$, could be determined. From the reaction conditions of different compositions, 4/6, 5/5, and 6/4 of PBT/ABA, at 250, 260, and 27$0^{\circ}C$, it was revealed that copolymerization between PBT and ABA proceeds on a pseudo-second order reaction if the ABA content and its conversion are low. In this case, the ratio of rate constants of homopolymerization to copolymerization was in the range from 1.08 to 3.17, indicating that the copolymer with more notable block character was obtained at the higher mole fraction of ABA and at higher temperature.e.e.

• Fibers and Polymers
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• v.4 no.4
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• pp.156-160
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• 2003

Poly(ethylene 2,6-naphthalate) (PEN)/Poly(ethylene glycol) (PEG) copolymers were synthesized by two step reaction during the melt copolymerization process. The first step was the esterification reaction of dimethyl-2,6-naphthalenedicarbox-ylate (2,6-NDC) and ethylene glycol (EG). The second step was the condensation polymerization of bishydroxyethylnaphthalate (BHEN) and PEG. The copolymers contained 10 mol% of PEG units with different molecular weights. Structures and thermal properties of the copolymers were studied by using $^1{H-NMR}$, DSC, TGA, etc. Especially, while the intrinsic viscosities of PEN/PEG copolymers increased with increasing molecular weights of PEG, but the glass transition temperature, the cold crystallization temperature, and the weight loss temperature of the copolymers decreased with increasing molecular weights of PEG. Consequently, the hydrophilicities by means of contact angle measurement and moisture content of the copolymer films were found to be significantly improved with increasing molecular weights of PEG.

• Bulletin of the Korean Chemical Society
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• v.29 no.12
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• pp.2373-2378
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• 2008

• Polymer(Korea)
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• v.39 no.2
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• pp.235-239
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• 2015

In this work, we evaluated catalytic activity of LiOH, $Cu(acac)_2$ and n-butyltin hydroxide oxide hydrate in the early stage of the melt transesterification of isosorbide and bisphenol A as diol monomers and diphenylcarbonate for the melt polymerizaiton of polycarbonate. $Cu(acac)_2$ proved to be the most active catalyst for homopolymerization process, while the catalytic activity of LiOH was higher than the others in case of melt copolymerization depending on the catalytic mechanism and chemical structure of catalyst. We suggested that evaluation of catalytic activity can be used for selection of catalyst system in bio-based copolymerization of polycarbonate.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1637-1642
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• 2013

We carried out the melt copolymerization reactions of 1,2-bis(diethylamino)tetramethyldisilane with several aryldiols such as, 4,4'-biphenol, 4,4'-isopropylidenediphenol, 9H-fluoren-9,9-dimethanol, and 4,4'-(9-fluorenylidene) bis(2-phenoxyethanol) to afford poly[oxy(arylene)oxy(tetramethyldisilylene)]s containing fluorescent aromatic chromophore groups in the polymer main chain: poly[oxy(4,4'-biphenylene)oxy(tetramethyldisilylene)], poly[oxy{(4,4'-isopropylidene) diphenylene}oxy(tetramethyldisilylene)], poly[oxy(9H-fluorene-9,9-dimethylene) oxy(tetramethyldisilylene)], and poly[oxy{4,4'-(9-fluorenylidene)bis(2-phenoxyethylene)}oxy(tetramethyldisilnylene)]. These prepared materials are soluble in common organic solvents such as $CHCl_3$ and THF. The obtained polymers were characterized by several spectroscopic methods such as $^1H$, $^{13}C$, and $^{29}Si$ NMR. Further, FTIR spectra of all the polymers exhibited characteristic Si-O stretching frequencies at 1014-1087 $cm^{-1}$. These polymeric materials in THF showed strong maximum absorption peaks at 268-281 nm, strong maximum excitation peaks at 263-291 nm, and strong maximum fluorescence emission bands at 314-362 nm due to the presence of tetramethyldisilylene and several arylene chromophores in the polymer main chain. TGA thermograms indicated that most of the polymers were stable up to $200^{\circ}C$ with a weight loss of 3-16% in nitrogen.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1303-1309
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• 2011

Melt copolymerization reactions of bis(diethylamino)tetramethyldisiloxane with several aryldiols were carried out to afford poly(carbotetramethyldisiloxane)s containing fluorescent aromatic chromophore groups in the polymer main chain: poly{oxy(4,4'-biphenylene)oxytetramethyldisiloxane}, poly{oxy(1,4-phenylene)oxytetramethyldisiloxane}, poly[oxy{(4,4'-isopropylidene)diphenylene}oxytetramethyldisiloxane], poly[oxy{(4,4'-hexafluoroisopropylidene)diphenylene}oxytetramethyldisiloxane], poly{oxy(2,6-naphthalene)oxytetramethyldisiloxane}, poly[oxy{4,4'-(9-fluorenylidene)diphenylene}oxytetramethyldisiloxane], poly{oxy(fluorene-9,9-dimethylene)oxytetramethyldisiloxane}, and poly[oxy{4,4'-(9-fluorenylidene)bis(2-phenoxyethylene)}oxytetramethyldisiloxane]. These materials are soluble in common organic solvents such as $CHCl_3$ and THF. The FTIR spectra of all the polymers exhibit the characteristic Si-O-C stretching frequencies at 1021-1082 $cm^{-1}$. In the THF solution, the polymeric materials show strong maximum absorption peaks at 215-311 nm, with strong maximum excitation peaks at 250-310 nm, and strong maximum fluorescence emission bands at 310-360 nm. TGA thermograms indicate that most of the polymers are stable up to $200^{\circ}C$ with a weight loss of less than 10% in nitrogen.

• Korea-Australia Rheology Journal
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• v.13 no.2
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• pp.61-65
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• 2001

Thermoplastic nanocomposites based on the copolymers of polypropylene (PP)-polystyrene (PS) and organically modified montmorillonite (org-MMT) were produced by using power ultrasonic wave in an intensive mixer. Owing to the unique action of the ultrasonic wave, free radicals of styrene monomers and macroradicals of PP were generated, by which copolymers of PP and PS were formed. Another important aspect of using ultrasonic wave during the mixing process was to enhance nano-scale dispersion of org-MMT by destructing the agglomerates of org-MMT in the polymer matrix. Optimum conditions for the in-situ copolymerization and melt intercalation were studied with various concentrations of styrene monomer, sonication time and different kinds of clay. It was found that a novel attempt carried out in this study yielded further improvement in the mechanical performance of the nanocomposites compared to those produced by the conventional melt mixing process.

• Macromolecular Research
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• v.9 no.3
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• pp.150-156
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• 2001

Polystyrenes(PS) were grafted onto polypropylene(PP) in the PP solution by ultrasonic irradiation-initiated polymerization of styrene. The resulting products consisted of mixtures of homopolymers and PP-PS copolymer because of the homopolymerization of styrene itself and copolymerization with PP. The dependency of the designated polymerization on sonication times was investigated to monitor the evolution lion of the copolymerization. Formation of the PP-PS copolymer was confirmed by FTIR analysis of the reaction products after a proper separation procedure of free PS and PP-PS copolymer. It was found that the tendency for the formation of PP-PS copolymer was closely related with the phase behavior of the PP/styrene mixture which was also influenced by sonication time. In order to verify the effectiveness of the PP-PS copolymer as a compatibilizer for PP/PS blend, melt mixing of PP/PS/PP-PS was performed in a batch mixer. During the mixing, the average torque was higher for the blend containing PP-PS copolymer influencing compatibilization. In accordance with the results from FRIR analysis and torque measurement, the PS domain size remarkably decreased in the PP/PS/PP-PS blend.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.2031-2036
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• 2012

Melt copolymerization reactions of several bis(diethylamino)silane derivatives, bis(diethylamino)methylphenylsilane, bis(diethylamino)methyloctylsilane, 1,2-bis(diethylamino)tetramethyldisilane, and 1,3-bis(diethylamino) tetramethyldisiloxane, with 2,7-dihydroxyfluoren-9-one were carried out to yield poly[oxy(2,7-fluoren- 9-onenylene)oxy(diorganosilylene)]s bearing the fluoren-9-one fluorescent aromatic group in the polymer main chain: poly[oxy(2,7-fluoren-9-onenylene)oxy(methylphenylsilylene)], poly[oxy(2,7-fluoren-9-onenylene) oxy(methyloctylsilylene)], poly[oxy(2,7-fluoren-9-onenylene)oxy(tetramethyldisilylene)], and poly[oxy- (2,7-fluoren-9-onenylene)oxy(tetramethyldisiloxanylene)]. These polymeric materials are soluble in common organic solvents such as $CHCl_3$ and THF. FTIR spectra of all the materials reveal characteristic Si-O-C stretching frequencies at 1012-1018 $cm^{-1}$. In the THF solution, the prepared materials show strong maximum absorption peaks at 258-270 nm, strong maximum excitation peaks at 260-280 nm, and strong maximum fluorescence emission bands at 310-420 nm. TGA thermograms suggest that most of the polymers are essentially stable to $200^{\circ}C$ without any weight loss and up to $300^{\circ}C$ with only a weight loss of less than 5% in nitrogen.

• Polymer(Korea)
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• v.31 no.4
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• pp.315-321
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• 2007

Aminated PONF-9-GMA ion exchange fabrics were synthesized by radiation induced graft copolymerization. Hybrid ion exchange fabrics combined with aminated PONF-g-GMA fabrics and anionic ion exchange resin were also fabricated by hot melt adhesion method and then their adsorption properties were investigated. Ion exchange capacity of the hybrid ion exchange fabrics was higher than ion exchange fabric and was lower than bead resin. The maximum value was 4.18 meq/g. Adsorption breakthrough time for vanadium of the hybrid ion exchange fabric was 550 min, which was faster than bead resin but slower than fibrous ion exchanger. The Breakthrough time of the hybrid ion exchange fabrics gets longer with increasing pH. The initial breakthrough time occurred around 400 min with increasing vanadium concentration.