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서길수,배광수 嶺南大學校 工業技術硏究所 1982 연구보고 Vol.10 No.1
. The shear rate dependence of viscosity and primary normal stress for a dilute solution of elastic dumbbells joined by a spring has been studied for steady shearing flow. Assumption that Frenkel model can be applied to describe the spring force of elastic dumbbell has been estabished. Hydrodynamic interaction has been neglected. Giesekus expression for the stress tensor has been used. So as to calculate the expectation value of stress tensor, the differential equation of distribution function has been solved by use of perturbation method. Material functions, viscosity and normal stress, have been integrated through the orthogonal relationships of spherical harmonics. Although the crudeness of the model, the results have been qualitatively in agreement with the experimental data in the small range of shear.
중합 반응의 모사 연구(I) : The Polymerization of Phenol-formaldehyde 페놀-포름알데히드의 중합 반응
서길수 嶺南大學校 工業技術硏究所 1983 연구보고 Vol.11 No.1
The polymerization and crosslinking of phenol-formaldehyde is a highly industrial process. However, the reactions that take place are quite difficult to handle in a quantitative manner for a number of reasons. There are significant different functional groups in phenol (i.e. in the different position on the ring). The polymerizaion of phenol-formaldehyde has been modelled through the use of species A to E. The effect of ratio of phenol and formaldehyde, concentration of water and vacuum has been examined. Analyses of the reactor under the variation of the ratio of phenol and formaldehyde in the feed shows that the maximum branching in the polymer occurs at the ratio of 0.5 whereas a ratio 1.6 is found to maximize the formation of linear chains.
서길수,이종두,김기덕 嶺南大學校 工業技術硏究所 1991 연구보고 Vol.19 No.1
The dispersion polymerization of phenol with formalin led to microspheric phenolic resin. The surface properties of these polymers were compared with those of microspheric resoroinolic resin, and it showed that it was possible to prepare microspheric carbon via pyrolysis of microsperic phenolic resin. In order to increase the electrical conductivity of microspheric carbon, we also tried to make metal-coated carbonic microsphere by nonelectrolytic metal coating process.
徐吉守,朴正學,金東洙,曺泰燮 嶺南大學校附設 基礎科學硏究所 1981 基礎科學硏究 Vol.1 No.-
Ni(Ⅱ) complexes with polyethyleneimine(PEI) as ligands were prepared in absolute ethanol by varying PEI/Ni(Ⅱ) mole ratio. The effects of PEI/Ni(Ⅱ) mole ratio and reaction temperature on the yield of the resulting complexes were investigated. It was observed that two types of octahedral complexes, [Ni(PEI)Cl₂] and [Ni(PEI)]Cl₂were obtained by varying PEI/Ni(Ⅱ) mole ratio from 0.5 to 7.0, and he structures of the complexes were characterized by ir and uv spectroscopy. The solubility behavior of the complexes in various organic and ionic aqueous solutions were also studied.
Poly-(dimethylsiloxane) Chain의 Configuration 성질
서길수,이병석 嶺南大學校 工業技術硏究所 1988 연구보고 Vol.16 No.1
We have been undertaken to compare the characteristic ratio <r²>。/nl² for the poly-(dimet-hylsiloxane) calculated by using trans-gauche rotational isomeric states model and the characte-ristic ratio deduced from intrinsic viscosity in two solvent: (ⅰ) θ-solvent(methyl ethyl ketone) at 20℃ and (ⅱ) benzene at 20℃. Though it is in good accordance between the calculated values and the experimental values in case of the molecular weight above 10⁴, it is not below 10⁴. The conformational specific heat dE conf/dT calculated near Tg is 0.03 cal/g℃. From this result, the importance of the contribution of conformational specific heat to the observed ΔCp has been recognized.
유성구,서길수 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.1
We have studied the melt intercalation of polyethylene oxide (PEO) into sodium montmorillonite (Na+-MMT), a layered silicate. X-ray diffraction experiments on polymer/silicate composite samples demonstrated that the intercalation of polymer chains leads to increase in the spacing between silicate layers. As the intercalation reaction proceeded, in the study of differential scanning calorimetry, more PEO chains were intercalated and the area of the endotherm corresponding to the crystalline PEO was reduced. And montmorillonite was organically modified with dodecylammonium bromide, to prepare the PCL/montmorillonite (DA-MMT) by melt intercalation, and PCL was intercalated into this organically modified montmorillonite at 80℃. X-ray diffraction results show that the intercalation of polymer chains leads to increase in the spacing between silicate layers (24.5Å). But the amount of PCL have no effect on the d-spacing of silicate layers. As the intercalation reaction progresses, from the results of DSC, heat of fusion and melting point were reduced.
유성구,서길수 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.1
The amorphous calcium carbonate was precipitated by adding Na2CO3 solution (1mol/ℓ) into CaCl2 solution (1mol/ℓ) and then the gel phases were filtered and dried rapidly through dry air under reduced pressure. These precipitated calcium carbonate were amorphous calcium carbonate from the results of XRD. In the solid states, amorphous calcium carbonate was crystallized into calcite at 274℃. And amorphous calcium carbonate in the water was crystallized into calcite at 20℃, vaterite at 50℃ and aragonite at 70℃, respectively
강재현,유성구,서길수 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.2
In this study, octadecyltrimethylammonium ion was intercalated in the gallery space of layered sodium montmorillonite(MMT) via an ion-exchange reaction. The gallery space was further modified by grafting of the aminopropyl groups via a reaction between a octadecyltrimethyl-ammonium-MMT intercalation compound and 3-aminopropyltriethoxysilane(APS) in order to use as a filler for epoxys-clay hybrid nanocomposites. The interlayer modification of MMT was confirmed by XRD, IR, and 29Si MAS NMR. Furthermore, the resulting hybrid nanocomposites were characterized by XRD, transmission electron microscopy(TEM) and scanning electron microscopy(SEM). The results proved that the organomontmorillonite could be exfoliated into ca. 100Å thickness and uniformly dispersed in the epoxy matrix.
Sol-Gel 반응을 통한 Surlyn/유기 실리케이트 나노복합재료 제조 및 물성에 관한 연구
차종현,정희정,서길수 한국공업화학회 2003 응용화학 Vol.7 No.2
Transparent organic-inorganic hybrid material was synthesized via the sol-gel method using polyethylene-co-methacrylic acid(PEMA) ionomer and a metal alkoxide, tetraethylorthosilicae(TEOS). The resulting material was characterized using ^(29)Si solid-state nuclear magnetic resonance spectroscopy results prove that silica is formed via the sol-gel reaction. Scanning electron microscopy analysis (SEM) , transmission electron microscopy (TEM) studies indicate that silica particle size is in nanoscopic level (70nm average size), and silica nanoparticles are uniformly dispersed in the polymer matrix after the sol-gel process. Theremogravimetric analysis (TGA) results show that the silica content of the hybrid. The thermal stability of the ionomer increases after hybridization. Material testing machine of the hybrid shows that the stress of ionomer increase after the sol-gel reaction.
김정필,최현국,서길수 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.2
Thermal responsive nanocomposite were synthesized by copolymerization of N-isopropyl acrylamide and methylene bisacrylamide(crosslinking monomer) in an aqueous suspension of MAPTC-montorillonite at room temperature. Hydrogels containing 2.0 ∼5.0wt% of montmorillonite exhibited a lower critical solution temperature(LCST) similar to unmodified PNIPAM hydrogel (approximately 33.7℃). However, hydrogels containing 10wt% montmorillonite did not exhibit a measurable LCST. TGA result shows thermal stability of thermal responsive nanocomposite imoroved a little more than the thermal responsive polymer.