• Proceedings of the Membrane Society of Korea Conference
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• 1999.04a
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• pp.86-89
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• 1999

• Journal of Environmental Science International
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• v.8 no.1
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• pp.61-67
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• 1999

Silicone oil has organic and inorganic properties, and its skeleton is polysiloxane bonding that silicon is bonded hydrogen or organic group. Silicone compounds are very smooth and lubricant properties by low surface tension, low temperature dependence, and nonadhesive properties. Because of these properties, silicone compounds are used as many parts of chemicals, softener, smooth and libricant agents, water-repellent agent, and defoaming agent, etc. Emulsion was prepared with the inversion emulsification method which adopted the agent-in-oil method dissolving the polyoxyethylene(7) tridecyl ether(HLB 12.2) into methoxy terminated poly(dimethyl-co-methyl amino) siloxane and hydroxy terminated poly(dimethyl-co-methyl amino) siloxane in water. At this time, processed emulsion was almost microemulsion. When ratio of emulsifier increases, emulsion is stable bacuause microemulsion is solubilized by emulsion drop size and zeta-potential are decreased. But, when amount of electrolyte is increase, emulsion became unstable because emulsion drop size is increased.

• Macromolecular Research
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• v.11 no.3
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• pp.202-205
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• 2003

The reactive precursors, vinyl ethers, and epoxy-silicones, were synthesized. The vinyl ether monomers were prepared from primary alcohol and ethyl vinyl ether with mercury (II) acetate. The epoxy-functionalized silicones have been achieved by the controlled, rhodium-catalyzed, chemoselective hydrosilation of vinyl ether with siloxanes or silane. It was shown that the hydrosilation proceeds exclusively at the vinyl ether group of alkenyl vinyl ether without participation at the alkenyl group. The photoinduced cationic polymerization of these monomers was studied and found to be all highly reactive.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.506-515
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• 1999

Dental practice can produce and spread some infectious diseases from patients to dentist, dental assistant, and dental labors. One possible method for preventing these cross-contamination is to immerse dental impression in chemical disinfectants. So for many investigators studied on the dimensional changes of dental impressions and on the surface qualities of stone casts made from impression following immersion in disinfectants. This study was proposed to evaluate some popular impression disinfectant combination from the point of dimensional stability. Impression was taken from dental arch-shaped metal model. Irreversible hydrocolloid and 3 elastomers(polyvinyl siloxane, polysulfide, polyether) were immersed in 3 disinfectants (2% glutaraldehyde, 1% povidone-iodine, 0.5% sodium hypochlorite) for 10 minutes and measured both cross-arch and anterior-posterior distance under stereo microscope to evaluate dimensional change. The results obtained were as follows: 1. Dimensional changes of irreversible hydrocolloid impression was statistically different in cross-arch and anterior-posterior distance when immersed in 2% glutaraldehyde solution and in anterior-posterior distance when immersed in 0.5% sodium hypochlorite solution from control group (p<0.05). 2. Dimensional changes of polyvinyl siloxane and polysulfide impression were not statistically different from control group (p>0.05). 3. Dimensional changes of polyether impression was statistically different in cross-arch distance when immersed in 0.5% sodium hypochlorite solution and in anterior-posterior distance when immersed in 1% povidone-iodine solution from control group (p<0.05). 4. In all cases, dimensional changes were less than 0.1% from the original dimension and concluded clinically acceptable.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.230-234
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• 2011

In this work, the primary material for a single layered hardmask which can afford a spin-on process was prepared by the minture of organic and inorganic sources. The preparation of hybrid polymer was attempted by esterification from silanol terminated siloxane compounds and acetonide-2,2-bis(methoxy)propionic acid. The optical, thermal and morphological properties of the test hardmask film was examined in terms of cross-linking agent and additives. In addition, the etch rate of hardmask film and photo resist layer were compared. The hybrid polymer prepared from organic and inorganic materials was found to be useful for hardmask film to form the nano-patterns.

• Imaging Science in Dentistry
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• v.32 no.3
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• pp.147-151
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• 2002

Purpose: To compare the standard deviation of gray levels on digital subtracted images obtained by different dental subtraction programs. Materials and Methods: Paired periapical films were taken at the lower premolar and molar areas of the phantoms involving human mandible. The bite registration group used Rinn XCP equipment and bite registration material, based on polyvinyl siloxane, for standardization. The no bite registration group used only Rinn XCP equipment. The periapical film images were digitized at 1200 dpi resolution and 256 gray levels by a flat bed scanner with transparency unit. Dental digital subtraction programs used for this study were Subtractor (Biomedisys Co., Korea) and Emago (Oral Diagnostic Systems, The Netherlands). To measure the similarities between the subtracted images, the standard deviations of the gray levels were obtained using a histogram of subtracted images, which were then analyzed statistically. Results: Subtracted images obtained by using the Emago program without manual selection of corresponding points showed the lowest standard deviation of gray levels (p<0.01). And the standard deviation of gray levels was lower in subtracted images in the group of a bite registration than in the group of no use of bite registration (p < 0.01). Conclusion: Digital radiographic subtraction without manual selection of reference points was found to be a convenient and superior method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.11
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• pp.810-815
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• 2013

In this study, the capacitance and dielectric loss tangent of the silicone rubber which is combined with filler (30 phr~50 phr) have been measured on the range of 100 Hz~100 kHz and $30{\sim}170^{\circ}C$. It was found that when the frequency is 0.1 kHz~100 kHz and the silicone rubber is combined with 30 phr to 50 phr of filler, the capacitance of silicone rubber has increased by about 28.6 pF to 33 pF in 30 phr of filler, about 20 pF to 46.1 pF in 40 phr of filler and about 36.4 pF to 44 pF in 50 phr of filler. It seems that the volume of dielectric loss has gradually increased due to the temperature rise and the rotating of dipole in electric field through the electric dipole generated by the Si-O group which is induced by adding of filler, or the carbonyl group which is caused by oxidation. It seems that the dielectric dispersion in 0.1 kHz is caused by molecular motion of Siloxane group in main chain, and the dielectric dispersion in 10 kHz is caused by molecular motion of Methyl group in side chain.

• Applied Chemistry for Engineering
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• v.2 no.4
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• pp.348-355
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• 1991

Polysiloxane copolymers were prepared by copolymerizing hexamethylcyclotrisiloxane with tetramethylcyclotetrasiloxane, and then reacted with allyamine. Copolymers containing naphthoquinone-1,2-diazide-5-sulfonyl group were synthesized by reacting naphthoquinone-1,2-diazide-5-sulfonyl chloride with siloxane copolymers having amino group. Thermal decomposition temperatures of copolymers were $360{\sim}450^{\circ}C$, and photosensitive characteristics were dependent on the molecular weights of backbone resins and sensitizers. Sensitivity of copolymers was $50{\sim}120mJ/cm^2$ and contrast(${\gamma}$) was 1.4~2.1.

• Macromolecular Research
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• v.12 no.5
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• pp.431-436
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• 2004

Cross-linked network solid polymer electrolytes were prepared by means of in situ hydrosilylation between poly[hydromethylslioxane-g-oligo(ethylene oxide)] and diallyl or triallyl group-containing poly(ethylene glycols). The conductivities of the resulting polymer electrolytes were greatly enhanced upon the addition of poly(ethylene glycol) dimethyl ether (PEGDME) as an ion-conducting plasticizer. Conductivities of the cross-linked polymer electrolytes were more dependent on the molecular weight of PEGDME than on the cross-linkers. The maximum conductivity was found to be 5.6${\times}$10$\^$-4/ S/cm at 30$^{\circ}C$ for the sample containing 75 wt% of PEGDME (M$\_$n/ =400). These electrolytes exhibited electrochemical stability up to 4.5 V against the lithium reference electrode. We observed reversible electrochemical plating/stripping of lithium on the nickel electrode.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.873-881
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• 2009

Bis(phenylethynyl)dimethylsilane is branched by the hydrosilation of the phenylethynyl group with dichloromethylsilane, and then the resulting chlorosilane is reacted with lithium phenylacetylide to give the $1^{st}$ generation. The same hydrosilation and alkynylation are repeated to obtain the $7^{th}$ generation. In addition peripheral Si-Cl moiety of the seven kind generation dendrimers are reacted with alcoholic moiety of 9-hydroxymethylanthracene and 2-(2-hydroxyphenyl)benzoxazole group in the presence of TMEDA. Then three kinds of carbosilane dendrimers are prepared from the $1^{st}$ to the $7^{th}$ generations, the $7^{th}$ generation of each dendrimer has 256 phenylethynyl, 256 9-anthracenylmethoxy, or 128 2-(2-phenoxy)benzoxazole groups. Each synthesized dendrimer is unequivocally characterized by $^1H\;and\;^{13}C\;NMR$, elemental analysis, MALDI-MS, GPC, and PL (photoluminescence). Characteristically PDI (Polydisperse Index) values of the dendrimers’ peak in GPC are in the range of $1.00{\sim}1.07$, which indicates that each generation of carbosilane is in unified distribution. PL spectra of phenylethynyl and 9- anthracenemethoxy group substituted dendrimers show no significant change with increasing the generation from the $1^{st}$ to the $7^{th}$. However, the PL spectra of 2-(2-phenoxy)benzoxazole group substituted dendrimers show a blue-shift trend with increasing the generation from the $1^{st}$ to the $7^{th}$.