• Polymer(Korea)
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• v.25 no.6
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• pp.811-817
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• 2001

Crystallization behaviour of bisphenol A polycarbonate(PC) from amorphous phase was studied by varing solvent/nonsolvent ratios in liquid phase. Chloroform and isopropanol were used as a solvent and a nonsolvent, respectively. Samples were characterized by optical microphotography, scanning electron microscope (SEM), X-ray diffaction (XRD), and differential scanning calorimeter (DSC). DSC and XRD measurement were used to determine the crystallinity of PC. The solubility constant seems to critical to control the PC crystallinity in solvent/nonsolvent mixture. The difference in PC crystallinity is explained by the difference in solubility constant of the mixture depending on the solvent/nonsolvent ratio. PC solution of 75/25 wt% (solvent/nonsolvent) ratio produced PC powder showing maximum crystallinity. At this condition solubility constant (9.85) of the mixed solvent was close to PC (9.9).

• Journal of the Microelectronics and Packaging Society
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• v.12 no.2 s.35
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• pp.141-147
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• 2005

Nanomaterial $TiO_2-SiO_2$ was synthesized by hydrolysis and condensation process using 2-propanol(2-PrOH) and was characterized by FT-IR, DSC, XRD and FE-SEM. FT-IR spectra were measured to investigate Ti-0-Si absorption peak. DSC thermal analysis results appllied to Ozawa equation were used to calculate to activation energy of crystallization. It was found that the changes of X-ray diffraction patterns and FWHM obtained XRD measurement depended on calcination temperature. In FE-SEM analysis, particle size changed by quantity changes of Ti-alkokide.

• Journal of Pharmaceutical Investigation
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• v.37 no.1
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• pp.23-26
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• 2007

Two crystal forms of cefuroxime axetil were obtained by the recrystallization from different organic solvents and characterized by differential scanning calorimetry (DSC), X-ray powder diffraction (XRD). It was confirmed that two crystal forms are identical. The dissolution patterns of these two forms were also checked in 0.07 N HCl at $37{\pm}0.5^{\circ}C$, 100 rpm for 180 minutes. The transformation during storage was also studied.

• Proceedings of the Korean Fiber Society Conference
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• 1996.10a
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• pp.212-217
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• 1996

방사속도를 500~5,500 m/min까지 변화시켜 만든 Poly(Ethylene 2,6-Naphthalenedicarboxylate)(PEN) 섬유의 Morphology 및 결정화거동을 DSC, XRD 및 Synchrotron Radiation을 이용하여 조사하였다. 밀도 및 복굴절률을 측정하여 방사속도가 증가함에 따라서 as-spun fiber의 구조를 살펴보았다. 또 DSC의 1차 승온과정으로부터 미연신사의 승온결정화 개시온도를 관찰하였으며 ㅡㅇ온결정화과정으로부터 결정화속도를 측정하였다. XRD 및 광가속도기를 이용하여 방사속도에 따른 섬유의 미세구조를 관찰하였으며 온도가 올라감에 따라 결정형태 및 결정화거동이 어떻게 달라지는지 확인하였다.

• Journal of Adhesion and Interface
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• v.10 no.1
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• pp.23-29
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• 2009

We investigated effects of a compatibilizer on the rheological properties during mixing and thermal properties of polypropylene (PP)-natural fiber composites. Two types of natural fibers (cotton fiber and wood fiber) were compared. maleic anhydride grafted PP was used for a compatibilizer. On increasing the amounts of the compatibilizer, the torque values of composites were increased, regardless of the kind of fibers. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results showed a slight increase in the degree of crystallinity with adding the compaibilizing agent, while the effects of the kind of fibers were marginal. It may be considered, however, the cotton fiber exhibits better interaction with PP-g-MAH than the natural fiber based on the rheographs, DSC, and XRD results.

• Journal of the Mineralogical Society of Korea
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• v.31 no.4
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• pp.227-234
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• 2018

In this work, we have prepared the reactive media with the pyrophyllite based using ceramic extrusion process. The characteristics of pyrophyllite were analyzed using XRD, XRF, DSC-TGA and Zeta-potential analysis. The study of pyrophyllite based ceramic reactive media were conducted under various roasting temperature (500 to $1,300^{\circ}C$) conditions. With increasing the roasting temperature, strength was increased but BET surface area was decreased. Thermally treated pyrophyllite were analyzed by means of weight loss and structural changes as detected by using XRD, DSC-TGA and SEM analysis. Pyrophyllite primarily transforms to pyrophyllite dehydroxylate after roasting at $1,000^{\circ}C$. Pyrophyllite dehydroxylate transforms to mullite and cristobalite at $1,300^{\circ}C$. This study demonstrates that pyrophyllite could be used as a reactive media for ceramic support layers from Permeable Reactive Barriers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.330-333
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• 1997

The thermal impact of mica/epoxy paper(130${\mu}{\textrm}{m}$) is investigated using XRD, DSC and TGL X-ray diffraction(XRD) analysis was performed to know the position and structure of mica crystal in insulation materials. A differential scanning calorimeter(DSC) was used to measure glass transition temperature and excess enthalphy of the composite materials that had been subjected to thermal aging. The glass transition temperature(T$_{g}$) measured by DSC is observed at 95.43$^{\circ}C$ and 113.43$^{\circ}C$, respectively. The T$_{g}$ also increases with increased aging time. Measurements performed by TGA(thermogravimetric analysis) have showed that weight loss profile of sound specimens are lower than those aged.ged.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.5
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• pp.405-410
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• 2020

In this study, the following results were obtained by analysis of electric properties with FT-IR, DSC, XRD, and SEM, in the range of temperature 30~160℃ and frequency 0.1~200 kHz, when filling agent (0~100 phr) and silicone oil (0~12 phr) were added to raw silicone rubber. In the case of 100 phr mixed samples, the relative dielectric constant εr gradually decreased from 4.3 to 3.96 as frequency increased, and the dielectric loss tan δ decreased to 0.01 at 300 Hz, then increased to 0.022 at 30 kHz, then decreased to 200 kHz. The FT-IR analysis identified the same binding structure according to the chemical composition of added silica (SiO₂). Through DSC analysis, we could determine the change of heat quantity and the glass transition temperature of each specimen. In the XRD analysis, it was found that the images SiO₂, TiO₂, and Fe₂O₃ appeared for specimens with 0%, 50% and 100% filling agent. Finally, the SEM analysis confirmed that particles of 0.5 to 1.5 ㎛ size with silica (SiO₂) mixing were dispersed evenly.

• Journal of the Korean Ceramic Society
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• v.41 no.5
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• pp.417-424
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• 2004

Polycarboxylate type superplasticizers (PCA) with different graft chain (Polyethylene oxide) length were synthesized by Methoxypoly (ethyleneglycol)monomethacrylate (MPEGMAA) and methacrylic acid (MAA). The effects of PCA on the hydration of Ordinary Portland Cement (OPC) were investigated by Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) techniques. The effect of graft chain length of PCA on the hydration of OPC was different at early age, but, at long age, was similar. The ratio of relative peak intensity, (I［001］/I［101］), of Ca(OH)$_2$ compared with OPC also was reduced by PCA addition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.4
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• pp.204-209
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• 2017

Thermal and structural stability in the glass transition region of chalcogenide glasses has been investigated in terms of thermodynamics for application to various optoelectronic devices. In this study, the compositions of $Ge_xSb_{20}Se_{80-x}$ (x = 10, 15, 20, 25, and 30) were selected to investigate the glass stability according to germanium ratios. The chalcogenide bulks were fabricated by using a traditional melt-quenching method. Thin films were deposited by a thermal evaporation system, maintaining the deposition ratio of $3{\sim}5{\AA}$ in order to have uniformity. The thermal and structural properties were measured by a differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The DSC analysis provided thermal parameters and theoretical glass region stabilities. The XRD analysis supported the theoretical stabilities because of where the crystallization peak data occurred.