• Elastomers and Composites
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• v.49 no.3
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• pp.225-231
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• 2014

In this study, we used polypropylene grafted with itaconic acid (PP-g-IA) as a compatibilizer to prevent phase separation phenomenon which occurs upon blending polypropylene (PP) and ethylene-vinyl alcohol copolymer (EVOH). A compatibilizer was prepared using graft copolymerization of itaconic acid (IA) onto PP where input ratio of IA was 1, 2, 5, and 10 wt.%. To confirm the structure of PP-g-IA and the graft ratio of IA onto PP, we used $^1H$ NMR and FT-IR. We tested the compatibilizer which has highest graft ratio of 1% in immiscible PP/EVOH blends. The morphologies of PP/PP-g-IA/EVOH blends were analyzed by SEM. Thermal and mechanical properties of the blends were analyzed by DSC and UTM. PP-g-IA enhanced the interfacial adhesion of PP and EVOH copolymer.

• Elastomers and Composites
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• v.49 no.3
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• pp.199-203
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• 2014

Terpolymer syrups were photopolymerized from 2-ethylhexyl acrylate, 2-hydroxylethyl acrylate and isobornyl acrylate to prepare acrylic pressure sensitive adhesives (PSAs). After polymerization, various crosslinkers as 1,6-hexanediol diacrylate (HDDA), poly (ethylene glycol) diacrylate (PEGDA, Mn = 250, 575, and 700) were added and then UV-irradiated to prepare the semi-IPN type PSAs. Their adhesion performance and storage modulus (G') were strongly dependent on their chemical structure and molecular weight of the crosslinkers. Optical properties such as transmittance (> 92.5 %), haze (< 1.0 %) and color-difference (< 0.3) of PSAs samples were not affected by crosslinker types used in this study.

• Membrane Journal
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• v.17 no.4
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• pp.359-368
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• 2007

The copolymer membranes, poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) were prepared by phase inversion method using as an additive with N,N-dimethylformamid as a solvent. The pores are generated during the solvent and non-solvent exchange process in the coagulation bath filled with non-solvent (distilled water). The highest porosity of the membrane was 60%. The surface and cross-section of the membranes was observed with a scanning electron microscopy (SEM). The mechanical property of the membrane was determined by using an universal testing machine (UTM). Tensile strength of measured membranes is presented the maximum 6.57 MPa at 30 wt% of PVdF-HFP.

• Journal of Pharmaceutical Investigation
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• v.34 no.3
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• pp.177-183
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• 2004

Recently, studies on intranasal mucosa delivery of influenza vaccine have been actively developed because of lack of pain and ease of administration. We studied on preparation of nanoparticle delivery system using biodegradable polymer as a poly(DL-lactide-co-glycolide) (PLGA) and their binding characteristics with vaccine. Three kinds of PLGA nanoparticles were prepared by spontaneous emulsification solvent diffusion (SESD) method using sodium dodecyl sulfate and sodium laurate as an anionic surfactant and Lutrol F68 (polyethylene glycol-block-polypropylene glycol copolymer) as a nonionic surfactant. The 5-aminofluorescein labeled vaccine was coated on the surface of nanoparticles by ionic complex. The complexes between vaccine and nanoparticles were confirmed by change of the size. After vaccine coating on the surface of anionic nanoparticles, particle size was increased from 174 to 1,040 nm. However the size of nonionic nanoparticles was not more increased than size of anionic nanoparticles. The amount of coated vaccine on the surface of PLGA nanoparticles was $14.32\;{\mu}g/mg$ with sodium dodecyl sulfate, $12.41\;{\mu}g/mg$ with sodium laurate, and $9.47{\mu}g/mg$ with Lutrol F68, respectively. In conclusion, prepared nanoparticles in this study is possible to use as a virus-like nanoparticles and it could be accept in the field of influenza vaccine delivery system.

• Polymer(Korea)
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• v.38 no.3
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• pp.307-313
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• 2014

The physical properties of functionalized graphene sheet (FGS)/poly(ethylene-co-vinyl acetate) (EVA) was examined with various kinds of EVA, having vinyl acetate (VA) contents in the range of 0 to 40 wt%. The compatibility between FGS and EVA was enhanced as the polar VA content of EVA increased. Thus, the dispersion of FGS in EVA became finer, and the decrease of surface resistivity and the increase of tensile modulus by the added FGS became more effective when the VA content of EVA was high. When the VA content was low, the elongation at break was reduced drastically by added FGS due to the poor adhesion of FGS/EVA interface. The crystallization of EVA was generally retarded by the interaction with dispersed FGS. However, when both the VA content of EVA and the added amount of FGS were low, the crystallization of EVA was enhanced, probably due to the predominant nucleating effect by FGS.

• Polymer(Korea)
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• v.38 no.3
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• pp.293-298
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• 2014

We prepared hydrophilic porous supporters for the reinforced composite fuel cell membrane by radiation grafting of acrylonitrile (AN) and hydrophilic sodium allylsulfonate (SAS) into a porous polytetrafluoroethylene (PTFE) supporter. The physicochemical properties of the supporters prepared under various reaction conditions such as molar ratio of SAS/AN, monomer concentration, and irradiation dose were evaluated. FTIR was utilized to confirm the successful introduction of SAS/AN copolymer chains into the porous PTFE. The pores of the porous PTFE film were found to be decreased with an increase in the degree of grafting by using FE-SEM and gurley number. Furthermore, by analyzing the degree of grafting, contact angle, and TBO (toluidine blue O) uptake, the hydrophilicity of the prepared supporters was found to increase with an increase in the degree of grafting.

• Composites Research
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• v.24 no.6
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• pp.1-6
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• 2011

A new water-soluble and self-doped poly(styrenesulfonic acid-graft-aniline), PSSA-g-PANI, for dispersing carbon nanotubes (CNTs) in water was synthesized and its ability to stabilize aqueous CNT dispersions was examined. It was observed that the PANI in PSSA-g-PANI, which has benzoid and quinoid structure, was strongly adsorbed onto the nanotube surface via a strong ${\pi}-{\pi}$ interaction, and thus only gentle sonication causes exfoliation of CNT ropes to small bundles and the long-term stability of their resulting dispersions was much better than commercial surfactants. Furthermore, when thin films of PSSA-g-PANI/CNT are prepared from aqueous dispersion and their electrical conductivities are measured by the four probe technique, it is observed that their conductivities are in the range of 1.5-2.5 S/cm.

• Polymer(Korea)
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• v.33 no.4
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• pp.371-376
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• 2009

The 1,3-propane diol has been introduced as a co-monomer with ethylene glycol to polymerize the poly(ethylene/propylene naphthalate) in order to improve the dimensional stability of poly(ethylene naphthalate) for a possible flexible substrate material. Based on $^1H$-NMR results, it was found that poly (ethylene/propylene naphthalate) has been synthesised successfully. Introducing 1,3-propane diol resulted in the amorphous state in polyester as well as lowering of glass transition and thermal degradation temperature. Coexisting relatively longer propylene segment compared with ethylene in synthesized polyester caused less orientation behavior and reducing thermal expansion coefficient. This is a promising result for poly (ethylene/propylene naphthalate) to apply a flexible substrate.

• Polymer(Korea)
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• v.33 no.4
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• pp.326-332
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• 2009

New humidity-sensitive monomer, N-methacryloyl-N'-ethyl-N'-propyl piperazinium bromide (MANEPPB) was prepared by the quaternization reaction of N-methacryloyl-N'-ethyl piperazine (MANEP) with 1-bromopropane. Polyelectrolytes derived from the copolymers composed of MANEPPB/MMN/AA=60/35/5, 70/25/5, 80/15/5, 90/5/5 and 95/0/5 were prepared for the humidity-sensitive membranes, which were fabricated on the gold electrode by dipping method and were crosslinked by reacting copolymers with aziridine crosslinker, trimethylolpropane tris(2-methyl-1-aziridinopropionate) (TTAP). When the resistance dependences on the relative humidity of the sensors were measured, it was found that the resistance varied three orders of magnitude between 20 and 90%RH, which was satisfied with the requirement for the common humidity sensor operating at ambient humidity. Their hysteresis, temperature dependence, frequency dependence, response and recovery time and water durability were measured and evaluated as a humidity-sensing membrane.

• Polymer(Korea)
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• v.32 no.3
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• pp.239-245
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• 2008

Block copolymers of the general formula $[(-CO-R'-CO-HN-Ar-NH-CO-R'-CO)_xNH(CH_2)_3-(Me_2SiO)_y(CH_2)_3NH_2]_n$, [n=18.00 to 1175.0] where $R'=CH_2CH(CH_2GeCl_3)$;$CH_2CHGeCl_3CH_2$; and $Ar=-C_6H_4$;$-(o.CH_3C_6H_4)_2$;$-o.CH_3OC_6H_4)_2$;$-(o.CH_3C_6H_4)$ were prepared by a polycondensation reaction of polyamide containing a pendant trichlorogermyl group and terminal acid chloride $Cl(-CO-R'-CO-NH-Ar-NH-CO-R'-CO-)_xCl$ with aminopropyl-terminated polydimethylsiloxane $H_2N(CH_2)_3(Me_2SiO)_y-(CH_2)_3NH_2]$, (PDMS). These polymers were characterized by elemental analysis, $T_g$, FT-IR, $^1H$-NMR, solid state $^{13}C$-NMR, and molecular weight determination. The thermal stability of these copolymers was examined using thermal analysis techniques, such as TGA and DSC. Their molecular weights as determined by laser light scattering technique ranged $5.13{\times}10^5$ to $331{\times}10^5\;g/mol$. These polymers display their $T_g$ in the range of 337 to $393^{\circ}C$ with an average decomposition temperature at $582^{\circ}C$.