• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.119-122
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• 2011

Among the developed bio-degradable polymer films as compared with transparent film(White), black polymer film was significantly more effective for controlling weeds in red pepper. Also, we found that white and black polymer mulching had 81.8% and 97.9% of managing weed controlling effects in rice, respectively. Compared to non-mulched rice paddy with water supply, the non-mulched rice paddy without any water supply has stopped its growth at 41 days after transplanting, while polymer-mulched rice paddy without water supply had about 60% of normally growing rice plants. This shows the polymer treatment has a remarkable effect on water and power saving, solution of herbicidal resistance, avoidance of herbicidal influence to eco-system etc. When the naturally decomposing polymer was used, a temperature was elevated as high as $4.7^{\circ}C$ on maximum and $2.6^{\circ}C$ on average. Also the naturally decomposing polymer accelerated rooting by 7 days and lowered a stress level from transplanting. The weed control effect mulched by polymer was remarkable as 98.7%. The polymer now, after 294 days treated on the rice paddy, has been completely decomposed.

• Polymer(Korea)
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• v.39 no.1
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• pp.6-12
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• 2015

In order to improve the poor water solubility of aceclofenac, it was loaded into solid Kollidon VA 64 dispersion prepared by spray drying and rotary evaporation methods using different drug and polymer ratios. Morphology and physicochemical behavior of the aceclofenac loaded solid dispersions was analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), and differential scanning calorimetry (DSC). Encapsulation efficiency and dissolution behavior in a simulated intestinal juice of aceclofenac in the solid dispersions was measured using HPLC and the latter was compared with that of the active pharmaceutical ingredient (API) and Airtal$^{(R)}$. It was demonstrated that two methods could significantly improve the dissolution behavior of aceclofenac.

• Polymer(Korea)
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• v.39 no.1
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• pp.33-39
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• 2015

Olmesartan affiliated to biopharmaceutics classification system class 2 is a poorly water soluble drug. For this reason, olmesartan showed a low bioavailability and a lot of difficulties in the process of designing the pharmaceutical formulation. We prepared the solid dispersions of olmesartan. We confirmed the dissolution rate of drug which was prepared by manufacturing. The pharmaceutical formulation of solid dispersions was designed by using PVP as water soluble polymer. We analyzed morphological feature of solid dispersion by employing a scanning electron microscope. Then, the crystalline property of solid dispersion was confirmed through X-ray diffraction and differential scanning calorimeter. Also, the chemical change of solid dispersion was confirmed by the Fourier transform infrared spectroscopy. In vitro dissolution test was used to analyze the dissolution rate of solid dispersion. The prepared solid dissolution olmesartan confirmed the dissolution rate in the pH 1.2. It was compared with olmetec and improved dissolution rate through solid dispersion.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.301-301
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• 2006

The physical properties of well-defined star-shape polystyrenes with high number of arms (6 to 57 arms) in good and theta solvents were studied using synchrotron X-ray scattering. The scattering profiles for multi-armed polystyrenes shown the molecular shape is changed according to increasing of number of arm. From various parameters which were obtained from scattering profiles, the molecular shape was determined more detail. As results, the molecular shape was changed from a fuzzy-ellipsoid for 6-armed PS to a fuzzy-sphere sphere for 57-armed PS according to increasing of number of arm.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.239-239
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• 2006

In the present study, we synthesized CBDA-FDA and its analogue, poly(4,4' -(9,9-fluorenyl)diphenylene pyromellitimide) (PMDA-FDA), and then investigated quantitatively the orientational distributions of the polymer chain segments in the surfaces of their films by using linearly polarized Fourier transform infrared (FTIR) spectroscopy and optical retardation analysis. We also examined the films' surface topographies using high spatial resolution atomic force microscopy (AFM). Further, rubbed films were used to assemble antiparallel and $90^{\circ}-twisted$ nematic (TN) LC cells, and the alignment behaviors, pretilt angles and anchoring energies of the LC molecules in the cells were determined. The films were found to have very interesting surface morphologies and LC alignment behaviors, which have not previously been reported. The observed LC alignments, pretilt angles and anchoring energies are discussed by taking into account the interactions of the LC molecules with the oriented polymer chain segments and the surface morphologies.

• Macromolecular Research
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• v.11 no.2
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• pp.98-103
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• 2003

The mechanical properties and failure mechanisms of through-the-thickness stitched plain weave glass fabric/polyurethane foam/epoxy composites were studied. Hybrid composites were fabricated using resin infusion process (RIP). Stitched sandwich composite increased drastically the flexural properties as compared with the unstitched fabrics. The breaking of stitching yarns was observed during the flexural test and this failure mode yielded relatively high flexural properties. Composites with stitched sandwich structure improved the mechanical properties with increasing the number of stitching yarns. From this study, it was concluded that proper combination of stitching density and types of stitching fiber is important factor for through-the-thickness stitched composite panels.

• Polymer(Korea)
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• v.38 no.5
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• pp.656-663
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• 2014

Atorvastatin calcium-loaded polyoxalate (POX) microspheres were prepared by an emulsion solvent-evaporation/ extraction method of oil-in-oil-in-water ($O_1/O_2/W$) for sustained release. We investigated the release behavior according to initial drug ratio, molecular weight ($M_w$) and concentration of POX and concentration of emulsifier. The microsphere was characterized on the surface, the cross-section morphology and the behavior of atorvastatin calcium release for 10 days by scanning electron microscopy (SEM) and high performance liquid chromatography (HPLC). The analysis of crystallization was analyzed to use X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared (FTIR). These results showed that the release behaviors can be controlled by preparation conditions.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.298-298
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• 2006

There has been much interest in incorporating nanoscale voids into dielectric materials in order to reduce their k value, and thus in producing low-k porous interdielectric materials. One approach to the development of low-k dielectric materials is the templated polycondensation of organosilicate precursors in the presence of a thermally labile, organic polymeric porogen. The other is SiOCH films have low dielectric constant as well as good mechanical strength and high thermal stability through PECVD. In this article we explore the nanopore generation mechanism of organosilicate film using star-shape porogen and SiOCH film using bis-trimethylsilylmethane (BTMSM) precursor.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.810-813
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• 2009

Fluorene derivatives are well-known in the polymer OLEDs due to their good charge carrying property. In this work, we synthesized a series of conjugated copolymers based fluorene derivative and phenylamine units by using Buchwald-Hartwig reaction in order to investigate their photoreactivities and use as the HIL/HTL layers of OLEDs using solution processes.

• Journal of Pharmaceutical Investigation
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• v.41 no.6
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• pp.363-369
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• 2011

In this study, we demonstrated the release behavior of carvedilol with the content of polyvinylpyrrolidone K-30 (PVP K-30) and the effect of citric acid and fumaric acid as acidifiers on the release behavior of drug. In addition, it tries to inquire into the release behavior difference of the carvedilol according to the manufacturing method. The release behavior of the tablets was compared with Dilatrand$^{(R)}$ in the simulated gastric fluid (pH1.2). Differential scanning calorimeter (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) were characterized for the physicochemical properties of the tablets. In case of mixing the carvedilol and PVP K-30, in case the ratio of the carvedilol and PVP K-30 was 1:5, the release behavior was the highest among. As well as the dissolution rate of tablets manufactured by lyophilization and rotary evaporator was higher than physical mixture. The dissolution rate of containing acidifiers was more improved. But, rather the excessive amount of the acidifier addition reduced the dissolution rate.