• Journal of the Korean Electrochemical Society
• /
• v.5 no.1
• /
• pp.13-16
• /
• 2002

The type of graphite(Gr)/ppy, fullerene$(full^-)$ electrode, ppy one modified with $(full^-)$, was prepared with the cell type of Gr/5mM ppy, 1mM $(full^-)$, 0.1M $TBABF_4$, CH3CN/Pt. The values of the ionic formation rate of the it at electrode materials such as Pt/ppy, Pt, Gr and Au were $93.6,\;7.0\times10^2,\;42.6\;and\;1.3\times10^2cms^{-1}$ respectively. The admittance values of the Grippy electrode and the modified Grippy, $(full^-)$ one were five times enhanced $1.7\times10^{-3}S\;to\;8.3\times10^{-3}\;S$ and capacitance values of electrical double layer of them were 174 times increased $2.4\times10^{-6}\;F\;to\;4.2\times10^{-5}\;F$ respectively.

• Applied Chemistry for Engineering
• /
• v.28 no.4
• /
• pp.454-459
• /
• 2017

In this study, aqueous acrylic emulsion adhesives were prepared using various surfactants and their properties were also investigated. Solids content, conversion, particle size distribution and initial adhesion properties of the prepared adhesives were compared with each other. The solid content of the adhesives was evaluated 60% and the conversion rate of the emulsion polymerization was 97% at 2 wt% concentration of synthesized surfactants. The particle size distribution analysis revealed that the size distribution of adhesive particles was 290~470 nm when the synthesized cationic surfactant was added. The initial adhesion and adhesion time were also improved. The maximum adhesive strength was found to be 2.55 kgf when using a single surfactant (POE 23), and superior to that of using other surfactants. It was confirmed that the corrosion inhibition of the adhesive prepared by adding the cationic gemini surfactant was maintained for 48 hours.

• Journal of the Korean Society of Tobacco Science
• /
• v.26 no.2 s.52
• /
• pp.159-167
• /
• 2004

This work has been conducted to select appropriate filter materials for removing carbonyl compounds in mainstream tobacco smoke. To investigate of the usability of this filter materials, two types of bead ion exchangers were synthesized and their adsorption characteristics for carbonyl compounds were investigated. Sulfonic acid group-containing cation exchanger and ammonium group-containing anion exchanger were synthesized by the suspension polymerization of glycidylmethacrylate(GMA) and divinylbenzene(DVB) followed by the subsequent functionalization, respectively. The removal efficiency of carbonyl compounds by these two ion exchangers increased in the presence of moisture. However, the amount of carbonyl compounds adsorbed on the anion exchanger was larger than that on the cation exchanger under two levels of water contents tested. This phenomenon seems to arise from the electron delocalization in carbonyl group of the anion exchangers. There was not any significant relationship between the amount of carbonyl compounds adsorbed on ion exchangers and the length of adsorption column. From the large ion exchange capacity and rapid ion exchange reaction rate of the anion exchanger, it is suggested that the anion exchanger may be a good filter material for removing carbonyl compounds in the mainstream tobacco smoke.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.5
• /
• pp.2451-2456
• /
• 2011

Inorganic micropowder(Ce500)-filled polyurethane composite foams were fabricated and the effects of postcure on the mechanical properties were studied by the measurement of polymerization temperature, TGA, and UTM test. Temperature for the maximum reaction rate of 20wt% Ce500-filled sample reached upto ca. $100^{\circ}$ within 10min. and, for the same sample, double mode thermal decomposition was observed around two distinguished temperatures of $250^{\circ}$ and $350^{\circ}C$. The activation energies for the decomposition were calculated using Kissinger method as 117.4 and 139.4 kJ/mol, respectively. While break strength and hardness of the sample seemed nearly affected by postcure time at $160^{\circ}C$, elongation, however, was significantly changed upto 1.72 times after 7hrs treatment. As the results, the condition of 7hrs at $160^{\circ}$ was considered as the optimum postcure condition for the Ce500-filled PU composite foam samples.

• Polymer(Korea)
• /
• v.34 no.6
• /
• pp.511-516
• /
• 2010

The electrochemical coating of poly(3-octylthiophene) on carbon materials was studied in order to investigate the application possibility of the modified carbon materials in the photoelectronic devices. Commercial carbon paper and carbon fiber were used as substrate electrodes for electrochemical coating. The coating behaviors were analysed with the variation of monomer and electrolyte concentration, applied potential, and cycling number in cyclovoltammetry. The coating rate of poly(3-octylthiophene) formed on the substrate were proportional to the monomer and electrolyte concentration, applied potential, and cycling number with each independent exponent. The structure and morphology of electrochemically polymerized poly(3-octylthiophene) was investigated with scanning electron microscopy and FTIR reflectance measurement.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.23
• /
• pp.10281-10287
• /
• 2015

Background: Development of a nanosized polymeric delivery system for erlotinib was the main objective of this research. Materials and Methods: Poly caprolactone-polyethylene glycol-polycaprolactone (PCEC) copolymers with different compositions were synthesized via ring opening polymerization. Formation of triblock copolymers was confirmed by HNMR as well as FT-IR. Erlotinib loaded nanoparticles were prepared by means of synthesized copolymers with solvent displacement method. Results: Physicochemical properties of obtained polymeric nanoparticles were dependent on composition of used copolymers. Size of particles was decreased with decreasing the PCL/PEG molar ratio in used copolymers. Encapsulation efficiency of prepared formulations was declined by decreasing their particle size. Drug release behavior from the prepared nanoparticles exhibited a sustained pattern without a burst release. From the release profiles, it can be found that erlotinib release rate from polymeric nanoparticles is decreased by increase of CL/PEG molar ratio of prepared block copolymers. Based on MTT assay results, cell growth inhibition of erlotinib has a dose and time dependent pattern. After 72 hours of exposure, the 50% inhibitory concentration (IC50) of erlotinib hydrochloride was appeared to be $14.8{\mu}M$. Conclusions: From the obtained results, it can be concluded that the prepared PCEC nanoparticles in this study might have the potential to be considered as delivery system for erlotinib.

• Nuclear Engineering and Technology
• /
• v.12 no.1
• /
• pp.1-8
• /
• 1980

The grafting studies were concentrated on working out the methodology for radiation of flame retardants to polyester/cotton (65/35) blend fabric. The Fyrol 76 was used as a flame retardant in develping methodology for localizing flame retardants on the surface of the blend fabric. By judicious control of the swelling conditions, time_of contact with the monomer, and dose rate, locating the graft in the fiber became possible. The yield of the graft polymerization was depended upon the total dose and the preswelling conditions. Oxygen Index was used to evaluate the effect of the location of Fyrol 76 and other flame retardants within the surface upon the flame retardance efficiencies. To get a better flame retardance efficiency by :the localized grafting of Fyrol 76 to polyester/cotton blend fabric, a technique of one step processing at room temperature was developed substituting the ordinary two-step processing at high temperature.

• Korean Chemical Engineering Research
• /
• v.48 no.4
• /
• pp.470-474
• /
• 2010

In this study, we presents a simple microfluidic approach for generating uniform Poly(ethylene glycol)(PEG) microfiber. Elongated flow pattern of monomer induced by sheath flow of immiscible oil as continuous phase is generated in Y-shape junction and in situ polymerization by UV exposure. For uniform microfiber, we investigate the optimized flow condition and draw phase diagram as function of Ca and Qd. At the region for stable elongated flow pattern, the microfiber generated in microfluidic chip is very uniform and highly reproducible. Importantly, the thickness of microfibers can be easily controlled by flow rate of continuous and disperse phase. We also demonstrate the feasibility for biological application as encapsulating FITC-BSA in PEG microfiber.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.5
• /
• pp.326-331
• /
• 2001

With the aim of developing of pH-sensitive controlled drug release system, a poly(Llysine) (PLL) based cationic semi-interpenetrating polymer network (semi-IPN) has been synthesized. This cationic hydrogel was designed to swell at lower pH and de-swell at higher pH and therefore be applicable for achieving regulated drug release at a specific pH range. In addition to the pH sensitivity, this hydrogel was anticipated to interact with an ionic drug, providing another means to regulate the release rate of ionic drugs. This semi-IPN hydrogel was prepared using a free-radical polymerization method and by crosslinking of the polyethylene glycol (PEG)-methacrylate polymer through the PLL network. The two polymers were penetrated with each other via interpolymer complexation to yield the semi-IPN structures. The PLL hydrogel thus prepared showed dynamic swelling/de-swelling behavior in response to pH change, and such a behavior was influenced by both the concentrations of PLL and PEG-methacrylate. Drug release from this semi-IPN hydrogel was also investigated using a model protein drug, streptokinase. Streptokinase release was found to be dependent on its ionic interaction with the PLL backbones as well as on the swelling of the semi-IPN hydrogel. These results suggest that a PLL semi-IPN hydrogel could potentially be used as a drug delivery platform to modulate drug release by pH-sensitivity and ionic interaction.

• The Journal of Korean Academy of Prosthodontics
• /
• v.46 no.6
• /
• pp.639-643
• /
• 2008

STATEMENT OF PROBLEM: The degree of conversion may influence the ultimate mechanical and physical properties of provisional crown and fixed partial denture materials. The high levels of the unreacted residual monomer may cause deleterious effect on the properties. PURPOSE: The purpose of this study was to measure the degree of conversion of bis-acrylic based provisional crown and fixed partial denture materials by using an infrared spectroscopic method. MATERIAL AND METHODS: Chemically activated three bis-acrylic based provisional crown and fixed partial denture materials, LuxaTemp [DMG, Hamburg, Germany], fast set TemPhase [Kerr, Orange, CA, USA] and Protemp 3 Garant [3M-ESPE, St Paul, MN, USA], were investigated by Fourier transform infrared spectrometry (FTIR). The FTIR spectra of the materials tested were immediately obtained after mixing. The specimens were stored under dry conditions and at $23^{\circ}C$ for 24 hours, and then the spectra of the materials were also obtained. The degree of conversion (%) was calculated from the spectrum of the absorbance between the aliphatic double bond at 1637 $cm^{-1}$ and the aromatic double bond at 1608 $cm^{-1}$ using the baseline method. The data were statistically analyzed using one-way ANOVA and the multiple comparison Scheffe test at the significance level of 0.05. RESULTS: The mean value and standard deviation of the degree of conversion were 52.5 % ${\pm}$ 1.1 %, 50.3 % ${\pm}$ 0.8 %, and 42.3 % ${\pm}$ 4.9 % for LuxaTemp, Protemp 3 Garant and fast set TemPhase, respectively. There was no significant difference between LuxaTemp and Protemp 3 Garant, whereas there was a statistically difference between Protemp 3 Garant and fast set TemPhase, and LuxaTemp and fast set TemPhase (P < .05). CONCLUSION: The degree of conversion of fast set TemPhase was significantly lower than those of the others. The degree of conversion may be correlated with the rate of polymerization.