• Magazine of the Korea Concrete Institute
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• v.7 no.2
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• pp.175-182
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• 1995

Styrene-Maleic anhydride copolymer (SMA) was prepared by the radical copolmerization of styrene and maleic anhydride using ${\alpha}-{\alpha}'$ azobis(isobutyronitrile) as an initiatrr. SMA was further reacted with m-amino phenol to obtain aminophenol-substituted SMR (mSMA). Sulfonated SMA and mSMA were also prepared by the reaction of copolymers with sulfuric acid The copolyniers were characterized by infrared spectroscopy. It was found from the results of elemental analysis that the substitution degree of aminophenol in the mSMR is 44% and the degree is lowered to 35% after sulfonation. The percentage of copolymers adsorbed on the surface of cement particles was increased with a decrease of added copolymers. While, the arnourit of sulfonated SMA absorbed on the surface of cement particles was larger than that of the sulfonated mSMA The copolymers synthesized in this study are probably expected as a high range water reducer for coiicxte.

• Polymer(Korea)
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• v.27 no.3
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• pp.242-248
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• 2003

PP-g-(AN/Sty) was synthesized by grafting with acrylonitrile (AN) and styrene (Sty) onto PP staple fiber using an electron beam accelerator and followed by amidoximination and phosphorylation. Mole fraction of AN in the graft chain increased with the increase of the AN content in the monomer mixture. The highest AN grafting yield of 45% was obtained at a monomer ratio of 40 vol% AN/60 vol% Sty. Mole fraction of AN in the graft chain decreased with the increase of methanol amount used its solvent. As reaction temperature increased, the grafting yield of copolymer increased and reached equilibrium at 50$^{\circ}C$. Amount of amidoxime group in fibrous ion exchanger was increased as increasing amount of hydroxylamine, and the maximum content of amidoxime group was observed at 5.8 mmol/g with the 9 wt% hydroxylamine concentration. Content of phosphorous group in fibrous ion exchanger increased up to 0.5 N phosphoric acid concentration, and then leveled off. The adsorption ability of the copolymer for uranyl ion by the chelating adsorbents was in the following order : bifunctional PP-g-(AN/sty) > amidoximated PP-g-(AN/Sty) > phosphorylated PP-g-(AN/Sty).

• Polymer(Korea)
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• v.25 no.5
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• pp.649-656
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• 2001

Miscibility of poly(4-vinylpyridine) (P4VP) blends with poly(vinyl acetate-co-vinyl alcohol) (VAc-VAL copolymers) was investigated as a function of comonomer composition of VAc-VAL copolymers. Differential scanning calorimetry (DSC) and thermo-optical microscopic (TOM) analysis confirmed that P4VP is miscible with VAc-VAL copolymers containing more than 30 mole% VAL. Fourier transform inflated (FT-IR) spectroscopic analysis revealed that the strong intermolecular hydrongen bonding interaction between the vinylpyridine and VAL hydroxyl group was formed. Theoretical phase diagram was constructed by the calculation using the Association model, a thermodynamic model for hydrogen-bonded polymer blend systems developed by Coleman et al. The calculated theoretical binodal phase diagrams were in good agreement with the experimentally determined cloud point curves.

• Polymer(Korea)
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• v.35 no.3
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• pp.223-227
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• 2011

Stimuli-responsive polymers have been investigated as the materials playing the critical roles in various applications. Thermoresponsive graft copolymers, poly (N-isopropylacrylamide)-g-hyaluronic acid (PNIPAAm-g-HA) and elastin-like peptide-g-hyaluronic acid (ELP-g-HA), were synthesized by coupling carboxylic polymers (PNIPAAm-COOH or ELP) to biocompatible HA through amide linkages. Thermoresponsive behavior was observed in both the copolymers, and the results of turbidity measurement were consistent with the results of rheological examination. Among the two copolymers, the ELP graft copolymer shows less cooperative LCST transition than the PNIPAAm case. As the content of graft chains of PNIPAAm and ELP increases, viscosity increases, and the increase was larger in PNIPAAm case at a graft content. These results shows us that the introduction of grafts provides thermosensitivity to biocompatible HA, whose characteristics can be engineered.

• Polymer(Korea)
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• v.32 no.6
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• pp.580-586
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• 2008

Copolyimides were synthesized from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 1,3-bis(3-aminophenoxy)benzene (BAPB) with different mole ratios of 2,2-bis[4-(4-aminophenoxy)pheny1]hexafluoropropane (BAPP). The solution cast film of poly(amic acid) (PAA) was heat treated at different temperatures to create copolyimide films. The PI copolymer films were found to exhibit good optical transparencies. The thermomechanical properties, morphology, and optical transparency of PI films were examined using fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (XRD), scanning electron microscopes (SEM), differential scanning calorimeter(DSC), thermo-gravimetric analyzer (TGA), universal tensile machine (UTM), and IN - Vis. spectrometer. The glass transition temperature ($T_g$), ultimate strength, and initial modulus linearly increased with increasing BAPP mole fraction. However, thermal stability($T_D{^i}$) of the copolyimide remains constant regardless of BAPP loadings. It was found, however, that the optical transparency decreases slightly upon increasing the BAPP content because of the formation of the charge transfer complexes.

• Polymer(Korea)
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• v.37 no.6
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• pp.736-743
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• 2013

Novel carbazole based copolymers were synthesized by Suzuki coupling polymerization. (Diphenylene)vinylene and n-octyl was introduced to carbazole as pendants for reducing band gap and improving solubility, respectively. Thermal, photoluminescence and electro-luminescence of copolymers were studied for applying the emitting layer of polymer light emitting diode (PLED). Maximum UV-vis absorption and photoluminescence (PL) emission wavelength of copolymers showed 333~340 nm and 409~464 nm in solution state, respectively. The relative quantum yield using 9,10-diphenylanthracene as a reference was 25.8%. These copolymers exhibited high thermal stability ($T_d$ = $350^{\circ}C$) and good film forming ability. Good luminance was obtained at voltages lower than 8 V and the onset voltage was observed at 4.0 V.

• Polymer(Korea)
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• v.35 no.6
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• pp.599-604
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• 2011

The PET-PEN copolymers have been synthesized and the effect of their morphology on the physical properties of polyester flexible substrate was investigated. It was found that the block sequence of synthesized copolymer was varied depending upon DMT/NDC ratio in polymerization. Higher PET-PEN and PEN block sequence in polyester copolymer resulted in the increase of glass transition temperature and it caused the enhancement of dimensional stability as a polyester flexible substrate. The highest coefficient of thermal expansion(CTE) was obtained when DMT/NDC ratio is 50/50. Synthesized PET-PEN copolymer seems to be acceptable as a flexible substrate since it shows that their optical transmittance at 550 nm is over 80% and thermal weight loss at $280^{\circ}C$ for 1 hr is less than 0.4 wt%.

• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.682-690
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• 1999

The quaternary random copolyesters of poly (butylene glutarate-co-adipate-co-succinate-co-terephthalate)(PBGAST) were synthesized and charaterized by $^1H-NMR$ spectrometry, DSC method, and X-ray diffractometry. Thus the melting point trends and crystallization behaviors of PBGAST copolyesters were obviously depended on terephthalate content in copolymers as well as reaction condition.

• Polymer(Korea)
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• v.24 no.6
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• pp.854-859
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• 2000

The synthesis of poly(N,N-dimethylamino ethyl methacrylate (DMAEMA)-block-poly(ethylene glycol) (PEG)) copolymer has been carried out and the block copolymer was characterized by FT-IR, DSC, and $^1$H-NMR. The formation of polymeric nanoaggregation was observed in the solution mixture of poly(DMAEMA) -block-PEG copolymer and poly (ethyl acrylamide) (EAAm) due to the intermolecular interaction via hydrogen bond between DMAEMA and poly(EAAm). The formation of polymeric nanoaggregation was observed above critical micelle concentration (CMC).

• Applied Chemistry for Engineering
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• v.18 no.2
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• pp.121-125
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• 2007

Siloxane monomer and oligomer were introduced to n-butyl acrylate and methyl methacrylate copolymer for improvement of water resistance and tactile sensation of acryl-type emulsion. Terpolymerimerization of n-butylacrylate, methyl methacrylate and siloxane monomer or oligomer was carried out in aqueous solution. The glass transition temperature (Tg) of terpolymer decreased with increasing siloxane monomer, however, the Tg of terpolymer increased with increasing siloxane oligomer due to the crosslinking of acrylated end group. The adhesion property and surface energy of the obtained terpolymer decreased with introducing siloxane monomer or oligomer in terpolymer. Decrement of tack and surface energy means the enhancement of water resistance and tactile sensation of the emulsion.