• Polymer(Korea)
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• v.25 no.3
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• pp.343-348
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• 2001

The mechanical and the platelet adhesion properties of the fluorinated polyurethane elastomers synthesized with a perfluorinated polyether diol (Fomblin ZDOL$ZDOL^{(R)}$) and 4,4'-diphenyl methane diisocyanate (MDI) were investigated. The change of mechanical properties with the Fomblin content and the type of the polyether diol was investigated by applying a designed technique using in vitro platelet adhesion test. As a result, the tensile properties were affected by the content and the type of nixed polyether diols. Also the platelet adhesion of polyurethane elastomers decreased with increasing the extent of fluorination in the polymer.

• Journal of the Korean Chemical Society
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• v.38 no.2
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• pp.129-135
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• 1994

Acyclic polyether dicarboxylic acid have been studied as metal cation carriers in a bulk liquid membrane system. The proton-ionizable ligands feature allows the coupling of a cation transport to reverse proton transport. This feature offers promise for the effective separation and concentration of metal cations with the metal cation transport being driven by a pH gradient. Metal cation transport increased regularly with increasing hydroxide($H^-$) concentration of source phase and with proton($H^+$) concentration of receiving phase. Competitive transport by the acyclic polyether dicarboxylic acids is selective for calcium ion over other alkaline-earth cations.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.10b
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• pp.114-116
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• 1999

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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• pp.363-373
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• 2006

Statement of Problem : The accuracy and dimensional stability of elastomeric impression materials have been the subject of numerous investigation. Few studies have addressed the effect of changes in time on the dimensional stability of impression materials. Purpose: The purpose of this investigation was to evaluate the effects of elastomeric impression materials and storage time on dimensional stability. Materials and methods: A total of 75 impressions were made of epoxy resin dies mimicked prepared 3-unit fixed partial denture. The dies had 1 buccolingual, 1 mesiodistal and 1 occlusogingival lines and interpreped dot. Impression materials investigated included two polyether impression materials and three polyvinylsiloxane impression material. 15 specimens were made of each impression material and poured by type IV stone over times (30 minutes, 24 hours, 72 hours) after mixing; the same examiner measured each specimen 3 times at a magnification of 3.5$\times$. All statistical tests were performed with the level of significance set at .05. Results : The results indicated that significant difference at any measuring point of stone dies of the polyether impression materials and when measurements at 30 minutes, 24 hours, and 72 hours were compared ; the length of measuring point increased significantly as time passed by. However this result is not significant clinically. Analysis also showed significant differences at any measuring point when polyvinylsiloxane and polyether impression materials were compared and significant differences clinically. Conclusion: Under the conditions of this study, the shrinkage rate of the polyvinylsiloxane and polyether impression materials significantly increased as time passed by. The polyether impression materials showed higher shrinkage significantly, while the shrinkage rate of all five materials showed a significant time-dependent increase.

• Bulletin of the Korean Chemical Society
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• v.22 no.10
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• pp.1076-1080
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• 2001

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.2
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• pp.207-218
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• 1993

The purpose of this study was to evaluate the reproducing accuracy of stone casts made from complete arch impressions using different impression materials. The impression materials studied were 1) polyether, 2) polysulfide, 3) polyvinyl siloxane, and 4) irreversible hydrocolloid. Impressions were made from a partially edentulous acrylic resin model with metal inserts in canine, first molar region bilaterally and mid palatal vault region. Each distance between 2 out of 5 meauring points was measured by using 3dimensional measuring machine. Impressions were poured at once with a type IV dental stone. Data were analyzed using t-test with a sample size of six. The results were as follow : 1. Polysulfide and polyether were significantly superior to polyvinyl siloxane and irreversible hydrocolloid in reproducing full arch model(p<0.05), but there were no statistical differences in amount of dimensional reproducing accuracy for full arch impression between polysulfide and polyether(p>0.05). 2. There were statistical differences in amount of dimensional reproducing accuracy between edentulous area and tooth bound area for polysulfide and polyether(p<0.05). but no statistical differences were observed for polyvinyl siloxane and irreversible hydrocolloid(p>0.05).

• Polymer(Korea)
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• v.25 no.1
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• pp.33-40
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• 2001

Fluorinated polyurethane elastomers were synthesized by two step polyaddition of a perfluorinated polyether diol(trade name of Fomblin $ZDOL^{\circledR}$) and diisocyanates such as 4,4'-diphenyl methane diisocyanate(MDI) and toluene 2,4-diisocyanate(TDI). In order to control the Fomblin moiety of the soft segment in the synthesized elastomers to 10~50%, polyether type polyols such as polypropylene glycol(PPG) and polytetramethylene glycol(PTMG) were mixed during the polymerization reaction. Ethylene diamine or 1,4-butane diol was used as chain extenders. The structure and average molecular weight of the produced polyurethanes were confirmed by using FT-IR, $^1H-NMR$, DSC, and GPC. The surface properties were analyzed by using X-ray photoelectron spectroscopy(XPS) and contact angle meter. From the results of the surface analysis it was concluded that the fluorine groups were localized on the surface rather than the inside of the polyurethane films.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1771-1776
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• 2007

The synthesis of well-defined dendrons based on aliphatic polyether dendritic cores and glassy polystyrene peripheries is described. The synthetic route involves a combination of living anionic polymerization and a stepwise convergent method consisting of iterative Williamson etherification and hydroboration/oxidation reactions. On the basis of molecular weight, as characterized by gel permeation chromatography (GPC), the first generation dendron (Generation-1) shows a random coil conformation like a linear polystyrene, while higher generations (Generation-2 and 3) reveal globular forms in solution.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.29-34
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• 2011

Hydroxyl terminated polyether(HTPE) propellants have been developed recently as possible replacements for HTPB/AP propellants currently used in a number of tactical rocker motor. As analyzing friability of HTPE and HTPB propellants in this study, the following results could be derived. The friability of the tested propellants depended on its binder contents, mechanical property, and burning rate. It was decreased as burning rate was lowered and toughness was increased.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.811-815
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• 2007

A series of bispyrenyl-polyether have been synthesized and investigated as a fluorescent chemosensor for metal ions. The results showed that bispyrenyl-polyether system is selective towards Al3+ ion over other ions tested. In free ligand, excited at 343 nm, it displays a strong excimer emission at around 475 nm with a weak monomer emission at 375 nm. A ratiometry of monomer (375 nm) increase and excimer (475 nm) quenching was shown only when Al3+ ion is bound to ligand, because two facing pyrene groups form a less efficient overlap of π?π stacking compared with that of free ligand.