• Polymer(Korea)
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• v.30 no.4
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• pp.318-325
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• 2006

Polypropylene-clay nanocomposites were studied by the modification of clay with amino silanes to introduce covalent bonds in nanocomposites, and prepared by melt-compounding with polypropylene, clay modified with amino silanes and maleic anhydride grafted polypropylene. The . .structure and surface properties of modified clay were determined by x-ray diffraction, infrared spectrum, and solid-state $^{29}Si$ nuclear magnetic resonance spectrum. The modification of clay with aminosilanes led to the increase of the silicate interlayers to about $19.8{\AA}$, the weakening effects of hydroxy group at $3650cm^{-1}$ and the signal of amine groups at -69 ppm proved that the modification had taken place.

• Polymer(Korea)
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• v.29 no.3
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• pp.314-319
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• 2005

Four kinds of new aliphatic diols were synthesized by the ring opening reaction of glycolide with 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, or 1,4-cyclohexanedimethanol, a difunctional initiator, in the presence of stannous octoate catalyst. The resulting diols were melt-polymerized with succinic acid, adipic acid, or suberic acid at 170, 190, or $220^{circ}C$ to produce new sequentially ordered aliphatic polyesters and their corresponding polyesters with random structure. Their glass transition temperatures ($T_g$) ranged from -40 to $30^{circ}C$, The sequentially ordered polyesters prepared at $170^{cir}C$ had higher $T_g$ of 5 to $10^{circ}$ than the polyesters with rand()m structure produced at higher temperature. From in-vitro degradation test the sequentially ordered polyesters was shower in the rate of hydrolysis in a buffer solution than the polymers with random molecular structure.

• Polymer(Korea)
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• v.29 no.3
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• pp.248-252
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• 2005

PP/MMT nanocomposites having a various compositions were prepared by melt blending with a twin screw extruder. In this study, maleic anhydride-grafted PP (MAH-g-PP) was used as a compatibilizer in order to assist the exfoliation or hen in the pp matrix. from the results or x-ray diffraction (XRD) and transmission electron microscope (TEM) measurements for the nanocomposites, we confirmed that MMT was exfoliated. PPM nanocomposites have shown good flame retardancy by synergistic effect between MMT and flame retardant. The mechanical and thermal properties of the nanocomposites showed significant enhancement compared with those of neat PP, The excellent flame retardancy of the PP/MMT nanocomposites, UL94 V-0 value, was successfully obtained with reduced amount of the flame retardant.

• Polymer(Korea)
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• v.29 no.3
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• pp.271-276
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• 2005

Polypropylene (PP)/montmorillonite (MMT) nanocomposites were prepared by melt mixing methods. MMT modified by dimethyl hydrogenated tallow 2-ethylhexyl ammonium (Cloisite 15A) was used. Polyolefine oligomer with telechelic OH groups was used as a compatibilizer. The degree of dispersion of MMT in the nanocomposites was measured by X-ray diffractometer and transmission electron microscope (TEM) images. MMT was well exfoliated when the contents of compatibilizer was 25 phr. The thermal stability that observed by thermogravimetric analysis (TGA) increased with the contents of MMT increased up to 5 phr. The complex viscosities and storage moduli of PP nanocomposites enhanced as the contents of compatibilizer decreased and those of MMT increased.

• Polymer(Korea)
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• v.26 no.3
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• pp.335-343
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• 2002

Blend resin (PET/PETG 70/30 blend) of poly (ethylene terephthalate) (PET) and poly (ethylene terephthalate glycol) (PETG) of weight percent 70/30 was prepared by a twin-screw extruder. Undrawn films of the blend and pure PETG were made by melt-press in hot press. Drawn films were made by capillary rheometer. Crystallinity, shrinkage, thermal, dynamic mechanical, and mechanical properties of these blends and PETG drawn films were investigated by wide angle X-ray diffractometer, dry oven, DSC thermal analyzer, and tensile tester. The crystallinity and density of these films increased with increasing draw ratio and draw rate but decreased with increasing draw temperature. The crystallinity and density of the blend films were higher than those of PETG films. The tensile strength and tensile modulus of these drawn alms increased with increasing draw ratio and draw rate but decreased with increasing draw temperature. The tensile strength and tensile modulus of blend films were higher than those of PETG films. Shrinkage of PETG md blend films decreased with draw ratio and draw rate. Shrinkage of undrawn blend film was 600% higher than that of pure PET film.

• 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.

• Polymer(Korea)
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• v.34 no.2
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• pp.144-149
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• 2010

Ag/polystyrene(PS) nanocomposites were prepared by in situ reduction of silver 2-ethylhexylcarbamate (Ag-CB) complex and follwing radical polymerization only by heating at 110 $^{\circ}C$. In contrast to this conventional heating method, the microwave irradiation afforded well-dispersed silver nanoparticles(NPs) in styrene monomer without polymerization. The synthesis of Ag NPs proceeded uniformly throughout the reaction vessel only under microwave irradiation, completing the reaction simultaneously in the whole reaction solution. Successive polymerization of the monomer containing the resultant NPs has successfully produced a hybrid of the silver NPs dispersed in PS matrix. Ag/PS (0.1/100) nanocomposites were prepared successfully by melt-mixing process using Ag/PS(4.0/100) as a master-batch. UV-VIS spectroscopy, TEM, and X-ray diffraction techniques were used to investigate the process of formation of Ag/PS nanocomposites.

• Polymer(Korea)
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• v.31 no.6
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• pp.479-484
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• 2007

In this study, the hybrid ion exchange fibers (HIEF) were prepared by using web spraying muthod with hot melt adhesive. Characteristics of HIEF and their adsorption properties for ammonia gas were investigated. The ion exchange capacity (IEC) of HIEF was increased with increasing the resin contents and their values were higher than those of pure resin and ion exchange fabrics. The removal efficiency for ammonia gas increased with an increase in packing density of hybrid ion exchange fabrics in the column. The adsorption breakthrough time was 270 min, which was slower than those of the resin and fibers. The maximum value of adsorption for ammonia gas was 94%. The breakthrough time was also increased with increasing the concentration and flow rate of ammonia gas. The reaction constant(k) for ammonia gas was increased with increasing the concentration and flow rate of the gas, while it was decreased an the mass was increased.

• Elastomers and Composites
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• v.48 no.4
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• pp.306-311
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• 2013

A series of liquid crystalline polyesters containing the 4-chloro benzoate group on the hydroquinone unit of rigid group were synthesized through solution polymerization of 2,5-di(4-chlorobenzoate)hydroquinones and 4,4'-dicarboxy-${\alpha},{\omega}$-diphenoxy alkane. The structure and properties for synthesized polymers were investigated by $^1H$-NMR, FT-IR, DSC, TGA, and POM. As result of investigations, The presence of the methylene group and bulky lateral groups in polymer chain have a great influence on the properties of polymers such as solubilities and thermal transitions. The optical textures of polymers revealed a weak birefringence in the melt and indicated that they form nematic mesophase. All polymers have very narrow mesophase temperature ranges.

• Polymer(Korea)
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• v.29 no.4
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• pp.399-402
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• 2005

In this study, ethyl cellulose (EC)/montmorilloniote(MMT) nanocomposite films plasticized with environmental-friendly plasticizer (BET, EBN, ESO) were prepared by melt process using Hakke mixer. The $T_g$ of plasticized EC films decreased from 122 to $71^{circ}C$ with the increase in the BET content up to 30 $wt\%$. The addition of 10 $wt\%$ epoxidized soybean oil (ESO) as the second plasticizer cause the further drop of $T_g$ from 81 to $61^{circ}C$. The plasticizer-effect of BET was better than that of EBN. When the plasticizer was added into the EC films, the mechanical properties of EC films was decreased, however the addition of monotmorillonite (MMT) into the EC films or the ring opening reaction of ESO plasticizer cause enhancement of mechanical properties.