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Hexamethyldisiloxane의 放射效果에 關한 硏究
孟琦錫 충남대학교 공업기술개발연구소 1976 工業技術開發硏究所論文集 Vol.3 No.1
The irradiation chemistry of hexamethyldisiloxane has been studied in detail and product yields have been established for both gaseous and liquid products. Significant differences from previously reported values, most notably in the methane and in low and intermediate molecular weight liquid product, were found. A materials balance is attempted and the products found are rationalized on the basis of fragmentation patterns found in mass spectrometric studies. The new G values are sufficiently different from previous report to have completely justified this investigation. More so in view of the fact that the present data are to be used as the standard for later investigation.
PVC 및 Olefin계 Copolymer의 열안정성에 관한 연구(Ⅰ) : 제조 및 내열성 Preparation and Heat Resistance
맹기석,송해영,박인환,황택성,민병철 충남대학교 공업교육연구소 1986 論文集 Vol.9 No.1
In order to improve the heat stability of poly(vinyl chloride), copolymerization of PVC and olefin was performed and the thermal properties of the copolymer was investigated. PVC-olefin copolymers with various olefin contents were prepared by a typical suspension polymerization method at 50℃. It was found that both the degree of conversion and molecular weight decreased as the comonomer ratio (olefin/VCM) in the copolymer was increased. Thermal analysis showed the higher content of olefin reduced the glass transition temperature(Tg) of the copolymer while the heat stability of the copolymer remained almost unchanged in terms of the initial decomposition temperature which is about the same as that of homo PVC. On the other hand, TGA analysis showed that the weight loss became smaller as the comonomer ratios of olefin was increased even though the molecular weight of the copolymer is lower. The polyene sequence distribution in the copolymer degraded at 120℃ was studied by UV-visible spectroscopy. It showed a trend that the amount of long polyene sequence increases at first as the comonomer ratio is increased, however a further increase of the comonomer ratio reverses the trend such that the short polyene sequence is more frequently found.
동위원소의 이온교환수지에 의한 분리 : 다공성이온교환수지(P-SSTDVB)의 합성과 리튬동위원소 분리에 관한 연구
맹기석,송해영,주혁종,황명천,김환영,류해일,서무열,김동원 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1
Suspension copolymerization of the styrene with divinylbenzene initiated by benzoylperoxide was carried out in presence of water and sodium chloride at 90℃. We used the toluene and heptance as diluents making the pore of the ion exchanger. Porous ion exchanger, sulfonated styrene-divinylbenzene was prepared by sulfonating porous styrenedivinylbenzene copolymer with cone-sulfuric acid and chlorosulfonic acid. A sulfonic acid group of sulfonated styrene-divinylbenzene copolymer was identified by means of infrared absorption spectroscopy. The pore volume of the styrene-divinylbenzene copolymer are increased as the mole fraction of the diluents and the contents of divinylbenzene, and then after it was sulfonated, the pore volume are decreased. Adsorption of metal ion for porous ion exchanger are also investigated. The distribution coefficients of various metal ions (Cr, Cd, Hg, Pb) for the porous styrene-divinylbenzene ion exchanger appears to give greater values than Dowex 50W-X8 ion exchanger. The cation-exchange resin employed were Dowex 50W-X8, 100∼200mesh and synthetic PSSTDVB(8%), 50∼200mesh, the eluents was a mole of hydrochloric acid. When used Dowex 50W-X8 and P-SSTDVB, respectively, it's isotope separation factor for lithium calculated from the isotope composition of the eluted fractions were 1.0011 and 1.0020.
Methylene-bis-salicylaldehyde 誘導體 合成과 反應速度에 관한 硏究
孟琦錫,김공수,宋海永 충남대학교 1977 工業技術開發硏究所論文集 Vol.4 No.2
Optimum conditions and reaction rates of synthesis of derivatives of methylene-bis-salicyl aldehyde from salicyl aldehyde and nitro salicyl aldehyde are as follows. a) In the synthesis 5,5'-methylene-bis-salicyl aldehyde, it is possible to get more then 40 percentages of yield at the 95℃ reaction temperature and more then 10 hrs reaction. b) In the synthesis of 3,3'-methylene-5,5'-dinitro-bis-salicyl aldehyde and 5,5'-methylene-3,3'-dinitro-bis-salicyl aldehyde it is possible to get more then 70 percentages of yield at 70℃ reaction temperature and one hour reaction.
環狀 Siloxane(D_4)의 Radiolysis에 關한 硏究
孟琦錫 충남대학교 공업기술개발연구소 1975 工業技術開發硏究所論文集 Vol.2 No.1
Radiolysis of octamethyl cyclotetrasiloxane(D₄) has been studied and product yields have been established for both gaseous and liquid products. Gas-Values of liquid products have been established using weight responce factor (R). The products found are nationalized on the basis of fragmentation pattern found in mass Spectrometric and retention times in chromatographic studies. The Values reported here in are to be utilized for comparison their values of linear and cyclicsiloxane.