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Joon-Pyo Jeun,Young-Chang Nho,Young-Kyou Jeon,Phil-Hyun Kang 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.3
Chitosan/poly(vinyl alcohol) (PVA) nanofibrousmats were prepared by the electrospinning method. The morphology and structure of electrospun nanofibers were investigated by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. SEM images showed that the uniform and bead-free fibers were obtained at concentrations greater than 8 wt%. Chitosan/PVAmats were irradiated with different doses (50–200 kGy) of 60Co gamma rays. The effect of irradiation dose on the mechanical and thermal properties of these films was also investigated. Increasing the irradiation dose led to a decrease in tensile strength. FT-IR and DSC demonstrated that there were strong intermolecular hydrogen bonds between the chitosan and PVA molecules.
The effect of Ne+ ion implantation on polyimide film
Joon-Pyo Jeun,Phil Hyun Kang,Jin-Wook Shin,Young-Chang Nho 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.1
The fluence of Ne+ ion irradiation on the surface modification of polyimide (Kapton HN type) film was investigated. The irradiation of ion implantation onto a polyimide film was performed, and the surface chemical structure was analyzed in detail by X-ray photoelectron spectroscopy (XPS). An acceleration voltage of 100 keV was used in the ion implantation with different doses from 5 × 1014 to 5 × 1017 ion ㎝-2 and a beam current density of 10 mA cm-2. The elemental ratios of carbon, oxygen and nitrogen were calculated from 1s peaks of the corresponding elements. The results showed that the content of carbon in the surface layer increased after ion irradiation, while the ratios of oxygen decreased after irradiation, especially in the case of the polyimide film treated at ion fluence. The O1s spectra after ion irradiation are related to the rearrangement of those recoil atoms and the ion incorporated into the film and the formation of new types of bond, such as C–O and O–O.
Jeun, Joon-Pyo,Hua, Zu Jian,Kang, Phil-Hyun,Nho, Young-Chang Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of applied polymer science Vol.115 No.1
<P>Electron-beam-radiation-induced grafting of acrylonitrile onto polypropylene fibers was investigated with a pre-irradiation method. Grafting conditions such as the solvents, additives, monomer concentration, radiation dose, and temperature were varied, and the effects on the degree of grafting were studied. The nature of the reaction medium and additives had a considerable influence on the degree of grafting. The dilution of acrylonitrile with N,N-dimethylformamide significantly enhanced the degree of grafting in comparison with other solvents. The addition of sulfuric acid to the reaction mixture led to an increase in the degree of grafting and an acceleration of the rate of grafting. The order of dependence of the rate of grafting on the pre-irradiation dose and monomer concentration was found to be 1.31 and 1.21, respectively, in the presence of sulfuric acid. The activation energy for grafting was calculated to be 21.9 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010</P>
Preparation of Ethyl-Cellulose Nanofibers via An Electrospinning
Jeun, Joon Pyo,Lim, Youn Mook,Choi, Jae Hak,La, Hyun Shil,Kang, Phil Hyun,Nho, Young Chang Trans Tech Publications, Ltd. 2007 Diffusion and defect data. SSP. [Pt. B], Solid sta Vol.119 No.-
<P>Ethyl-cellulose (EC) nanofibers were fabricated by an electrospinning of an EC solution with a 6-12 wt% concentration. Fiber morphology was observed under a scanning electron microscope and the effects of instrument parameters including the solution concentration, flow rate and electric voltage were investigated.</P>
Jeun, Joon-Pyo,Jeon, Young-Kyou,Nho, Young-Chang,Kang, Phil-Hyun Elsevier 2009 Journal of industrial and engineering chemistry Vol.15 No.3
<P><B>Abstract</B></P><P>Chitosan/poly(vinyl alcohol) (PVA) nanofibrous mats were prepared by the electrospinning method. The morphology and structure of electrospun nanofibers were investigated by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. SEM images showed that the uniform and bead-free fibers were obtained at concentrations greater than 8wt%. Chitosan/PVA mats were irradiated with different doses (50–200kGy) of <SUP>60</SUP>Co gamma rays. The effect of irradiation dose on the mechanical and thermal properties of these films was also investigated. Increasing the irradiation dose led to a decrease in tensile strength. FT-IR and DSC demonstrated that there were strong intermolecular hydrogen bonds between the chitosan and PVA molecules.</P>