• Polymer(Korea)
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• v.29 no.2
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• pp.156-160
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• 2005

$\alpha,\omega-Vinyl$ poly (dimethyl-methylphenyl) siloxane prepolymer (VPMPS ) was prepared by the equilibrium polymerization of octamethylcyclotetrasiloxane $(D_4)$, 1,3,5-trimethyl-1,3,5-triphenylcyclotrisiloxane $(D_3^{Me,Ph)$, and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane (MVS). And also, of $\alpha,\omega-hydrogen$ poly(dimethyl-methyl)siloxane prepolymer (HPDMS) as end blocker was prepared from octamethylcyclotetrasiloxane $(D_4)$, 1,3,5-trimethylcyclotrisiloxane $(D_3^:Me,H})$, and 1,1,3,3-tetramethyldisiloxane (MS). Nickel ferrite nanoparticles having spinel magnetic material was prepared by the sol-gel method using PAA as a chelating agent. Poly(organosiloxane) rubber nanocomposite containing silica and nickel ferrite ultrafine powder modified with 1,3-divinyltetramethyldisilazane (VMS) was prepared by compounding VPMPS, HPDMS, and catalyst in high speed dissolver. The mechanical properties, heat dissipating away characteristics, and volume resistivities for POX-30 and POX-50 were measured.

• Elastomers and Composites
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• v.44 no.1
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• pp.34-40
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• 2009

New coupling agent or surface modified agent (9-decenoic acid) was used to enhance the compatibility between silica and polystyrene in silica/polystyrene hybrid nanocomposite, synthesized by in situ miniemulsion polymerization. Composites contain well dispersed nanosize silica particles. Related tests and analyses confirmed the success of synthesis. Functionalization of silica by 9-decenoic acid and silica on the polystyrene was confirmed by FTIR. TGA showed presence and amount of silica in final latex. The glass transition temperature of the hybrid nanocomposite was increased with the silica amount. SEM and TEM analysis showed the spherical morphology of PS and composite with an average diameter of 55 nm. The presence of silica within composite was confirmed by EDS attached to the existing TEM.

• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.222-227
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• 2010

This study added Au colloid in martial of conventional contact lens in various concentrations and copolymerized by heating at $70^{\circ}C$ for 40 minutes, $80^{\circ}C$ for 40 minutes, and finally, $100^{\circ}C$ for 40 minutes. Using the polymer produced through the copolymerization process, we have produced a contact lens and measured the physical characteristics which showed oxygen transmissibility of $9{\sim}12{\times}10^{-9}$ cm/s mL $O_2$/mL ${\times}$ mmHg, water content of 27.84% ~ 32.17%, refractive index of 1.432 ~ 1.443, visible transmittance of 83.2% ~ 89.5% and tensile strength of 0.141 kgf ~ 0.152 kgf. The polymer satisfied the physical properties required to produce contact lenses. Also, we judged that the polymer is suitable to be applied as a functional material for ophthalmological purposes.

• Polymer(Korea)
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• v.37 no.4
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• pp.470-477
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• 2013

Multi-walled carbon nanotube (MWCNT) based nano-composite pastes having a high filler content are prepared for the facile fabrication of a counter electrode (CE) of dye-sensitized solar cell (DSSC). A polystyrene-based functional block copolymer is prepared through a controlled "living" radical polymerization technique, affording a surface modifier for the dispersion control of MWCNT in the paste. Physical dispersion through a ball-milling method additionally confirms the importance of the dispersion control, providing DSSC with enhanced processibility and improved solar-to-electricity energy conversion efficiency (${\eta}$) values. The performances of the DSSCs are further improved through the incorporation of minor amount of platinum (Pt) nanoparticles into the MWCNT pastes. The DSSC with the Pt/MWCNT hybrid CE exhibits very high ${\eta}$ values, which is superior to that of DSSC with the standard Pt CE.

• Polymer(Korea)
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• v.29 no.1
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• pp.8-13
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• 2005

Polystyrene (PS) particles containing the phase change material (PCM) were synthesized by miniemulsion polymerization. The polymer particles prepared with different parameters were investigated in terms of average particle size, particle distribution, and latent heat storage of encapsulated paraffin wax (PW) as PCM. The morphology and particle features of PS particles were analyzed by scanning electron microscope and particle size analyzer, respectively. As a result, the diameters of PS particles were adjusted with manufacturing conditions. The stable and spherical PS particles of nanosize were obtained by miniemulsion polymerization, which could be attributed to the prevention of Ostwald ripening by cosurfactant. Thermal properties of PS particle containing PCM were studied by differential scanning calorimetry. From DSC freeze-thaw cycle, PCM coated with PS exhibited the thermal energy storage and release behaviors, and the latent heat was found to be a maximum 145 J/g. It was noted that PS particles containing PCM showed a good potential as a thermal energy storage medium.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.51-56
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• 2023

Composite membranes consisting of TiO₂ nanoparticles (NPs) and porous polymers have been widely utilized in photocatalytic water treatment because the composite membranes can allow an easy recovery of NPs after the photocatalytic reaction as well as the reduction of fouling in the membrane. However, the photocatalytic efficiency of the immobilized TiO₂ NPs in the composite membranes has been discussed to a limited degree. In this study, we prepared polyethersulfone (PES)/TiO₂ composite membranes to study the photocatalytic decomposition of organic dyes under light illumination. The decomposition kinetics of dye molecules by the PES/TiO₂ composite membranes and colloidal TiO₂ NPs have been compared to discuss the photocatalytic efficiency of NPs before and after their immobilization on the polymer membrane.

• Korean Journal of Veterinary Research
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• v.57 no.2
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• pp.105-111
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• 2017

Hyaluronic acid (HA) has been investigated for biomedical and pharmaceutical applications. This study was conducted to determine the distributions of HA nanoparticles (NPs; size 350-400 nm) and larger HA polymers in mice at intervals after application. $^{177}Lutetium$ (Lu)-labeled HA-NPs or HA polymers were intravenously injected (5 mg/kg) into male ICR mice, and radioactivity levels in blood and target organs were measured from 0.25 h to 28 days post-injection. In blood, the radioactivities of HA-NPs and HA polymer peaked at 0.5 h after injection but were remarkably decreased at 2 h; subsequently, they maintained a constant level until 6 days post-injection. HA-NPs and HA polymers were observed in the liver, spleen, lung, kidney, and heart (in ascending order) but were seldom observed in other organs. After 3 days, both the HA-NP and HA polymer levels showed similar steady decreases in lung, kidney, and heart. However, in liver and spleen, the HA-NP levels tended to decrease gradually after 1 day and both were very low after 14 days, whereas the HA polymer level accumulated for 28 days. The results indicate that HA-NPs, with their faster clearance pattern, may act as a better drug delivery system than HA polymers, especially in the liver and spleen.

• Advances in materials Research
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• v.1 no.2
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• pp.161-168
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• 2012

Nanoflake composite multi core-shell $SrFe_{12}O_{19}/Fe_3O_4$/PEG/Polypyrrole was synthesized by in situ polymerization method. In this paper, the fabrication of $SrFe_{12}O_{19}$ nanoflake is as first core by solgel method. Then fabricated a shell layer from magnetic nanoparticles of $Fe_3O_4$, which synthesized by coprecipitation technique, onto the $SrFe_{12}O_{19}$ nanoflake. Polyethylene glycol (PEG) as a polymer layer and as second shell was coated onto the before core-shell. Than core-shell $SrFe_{12}O_{19}/Fe_3O_4$/PEG was used as template for the preparation of $SrFe_{12}O_{19}/Fe_3O_4$/PEG/Polypyrrole composite. Final composite has a conductive property among $4.23{\times}10^{-2}Scm^{-1}$ and magnetic property about $M_s$=2.99 emu/g. Also final composite in soluble at organic solvent such as DMF and DMSO and has a flake structure. Conductivity and magnetic property respectively determine by four-probe instrument and vibrant sample magnetometer (VSM), morphology and article size determined by FE-SEM, TEM and XRD.

• Advances in nano research
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• v.2 no.2
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• pp.111-119
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• 2014

The chemical synthesis of anisotropic defective polyaniline/Ag composite (PANI/Ag) is explored using silver nitrate ($AgNO_3$) as the precursor material. This study provides a simple method for the formation of PANI/Ag nanocomposites at two different aniline concentrations $5{\mu}l$ (PANC5) and $10{\mu}l$ (PANC10). The composite PANC5 exhibits UV-Visible absorption peaks at 436 nm and 670 nm whereas, PANC10 exhibits absorption peaks at 446 nm and 697 nm. This shift is caused by the strong interaction between polyaniline and silver. The characterized FTIR peaks observed at around $3410cm^{-1}$ (PANC5) and $3420cm^{-1}$ (PANC10) was due to the N-H stretching vibrations. The appearance of a broad band instead of a sharp peak can be attributed due to the presence of a high concentration of N-H groups in the nanocomposite. The TEM images show that the sample contains defective spherical, truncated triangular and rod shaped particles. The results showed that the PANI/Ag nanocomposites are composed of nano-sized particles of 43-53 nm that contain Ag domains of 33-37 nm with polymer thickness 5.7-11.2 nm at two different aniline concentrations.

• Archives of Pharmacal Research
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• v.25 no.3
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• pp.229-239
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• 2002

Recent progress in understanding the molecular basis of cancer brought out new materials such as oligonucleotides, genes, peptides and proteins as a source of new anticancer agents. Due to their macromolecular properties, however, new strategies of delivery for them are required to achieve their full therapeutic efficacy in clinical setting. Development of improved dosage forms of currently marketed anticancer drugs can also enhance their therapeutic values. Currently developed delivery systems for anticancer agents include colloidal systems (liposomes, emulsions, nanoparticles and micelles), polymer implants and polymer conjugates. These delivery systems have been able to provide enhanced therapeutic activity and reduced toxicity of anticancer agents mainly by altering their pharmacokinetics and biodistribution. Furthermore, the identification of cell-specific receptor/antigens on cancer cells have brought the development of ligand- or antibody-bearing delivery systems which can be targeted to cancer cells by specific binding to receptors or antigens. They have exhibited specific and selective delivery of anticancer agents to cancer. As a consequence of extensive research, clinical development of anticancer agents utilizing various delivery systems is undergoing worldwide. New technologies and multidisciplinary expertise to develop advanced drug delivery systems, applicable to a wide range of anticancer agents, may eventually lead to an effective cancer therapy in the future.