• Polymer(Korea)
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• v.39 no.2
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• pp.311-316
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• 2015

Densely structured polyhedral oligomeric silsesquioxane (POSS) was employed as an additive to enhance hardness of silicon-based hybrid gels for LED encapsulants. To improve the miscibility of POSS and polysiloxane resin, alkyl or oligosiloxane branches were introduced to POSS moiety. Platinum-catalyzed hydrosilylation reactions were used to attach branches of 1-decanol, 9-decen-1-ol, and vinyl-terminated oligosiloxane to the POSS molecules. Alkyl-branched POSSs (decyl-POSS and decenyl-POSS) were immiscibile with polysiloxane resin and generated gels with low transparency and low hardness values. On the other hand, oligosiloxane-branched POSS (Siloxy-POSS) showed good miscibility with polysiloxane resin to give gels with high transparency. However, the prepared gels did not show noticeable improvement in hardness compared to the gels without the POSS additive.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.332-337
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• 2008

Hydrosilylation reaction of 1,1,1,3,5,5,5-heptamethyl trisiloxane (HMTS) and unsaturated poly(oxyethylene) (UPOE) was carried out in the presence of Speier's catalyst. The effect of molar ratio of two reagents on the reactivity and the structure of the product (HMTS-POE) were investigated by FT-IR and $^1H-NMR$. The pure HMTS-POE without containing unreacted HMTS or UPOE could be obtained by the reaction with excess amount of HMTS and followed by removing unreacted HMTS under vacuum. Under the same reaction conditions, various HMTS-POEs composed of UPOEs with a different molecular weight were synthesized, and the surface tensions of HMTS-POEs were analyzed. HMTS-POE, whose EO contents are in the range of 49~57%, exhibited lower surface tension and a potential application for low molecular weight silicone modified with polyethers.

• Journal of the Korean Applied Science and Technology
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• v.26 no.4
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• pp.379-384
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• 2009

Epoxy resin based encapsulants are widely used in semiconductor packaging applications. Epoxy resin based encapsulants are often subject to crack or delamination during the reliability test due to the thermal stress caused by high modulus nature of epoxy resins. Epoxy functional siloxanes are often added into epoxy resin to reduce the modulus so that the thermal stress can be reduced. Epoxy functional siloxanes, additives for reduced modulus, were synthesized and added into the curable epoxy resins. The modulus and the coefficient of thermal expansion (CTE) were also measured to investigate the thermal stress and to see whether the epoxy functional siloxane adversely affects the CTE or not. As a result, around 26% to 72% of thermal stress reduction was observed with no adverse effect on CTE.

• Journal of Integrative Natural Science
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• v.4 no.3
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• pp.182-186
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• 2011

Chemical modification of porous silicon surface has been investigated to have different physical surface properties. Porous silicon modified with dodecyl functionality exhibits hydrophobic feature, however the oxidation of porous silicon to modify with hydroxyl group displays hydrophilic properties. Surface characterization for both dodecyl and hydroxyl derivatized porous silicon was investigated by FT-IR spectroscopy. To determine the surface coverage, the amine functionalized surface was reduced by dithiothreitol (DTT) and the released 2-thiopyridone was quantified by UV/vis spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1665-1669
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• 2014

Four multialkoxy-functionalized siloxane base-polymers (BP-1~4) were synthesized through either hydrosilylation or condensation reactions in order to prepare multi-networked siloxane polymers having appropriate physical properties for protective coating in fabrications of electronics. Formulations of 4 base-polymers gave coating materials A and B. Product A showed well-controlled flowing and leveling properties, and product A-2 was successfully applied to protective insulating coating for junction areas of connectors and chips in PDP controller. Tack free time, extrusion rate, dielectric breakdown voltage, hardness, thermal stability, water resistance and flame resistance of products A and B were examined.

• Rapid Communication in Photoscience
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• v.4 no.1
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• pp.16-18
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• 2015

Luminescence properties of anthracene chromophores were investigated. Anthracene chromophores were incorporated in cyclosiloxane-based hybrid polymers through one-pot hydrosilylation reaction. Using four-armed cyclosiloxanes, divinylterminated siloxane monomers, and 9-vinylanthracenes, anthracene-labeled hybrid polymers were prepared. Free-standing hybrid polymer films were prepared successfully by doctor-blade method and thermal treatment. The polymer films exhibit strong blue fluorescence from anthracene and its fluorescence lifetime was not influenced by the temperature, indicating that the movement of anthracene chromophores was restrained in cyclosiloxane-based hybrid polymer films.

• Macromolecular Research
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• v.17 no.9
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• pp.651-657
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• 2009

This study examined the optimum compositions of binder, photo-acid generator (PAG) and sensitizer for the cationic ring opening polymerization of 1,3-bis[2-(3-{7-oxabicyclo-[4.1.0]heptyl})]-tetramethyldisiloxane in the presence of polydimethylsiloxane with four epoxide moieties as a co-monomer. When diffractive efficiency (DE) values were compared quantitatively to analyze the effect of the binder on holographic photopolymerization, DE was affected by the viscosity of the binders and miscibility with the monomer mixture. Extremely low DE values were observed when the immiscible dimethyl silicone was used as a binder. Therefore, methylphenyl silicone, which is miscible with the monomer mixture, was used as the binder for further studies. The optimal conditions were a binder viscosity between 250 to 390 cP, and contents of the binder, PAG, and sensitizer were 75-125 wt%, > 6 wt% and 0.05 wt% to the total monomer mixture, respectively.

• 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.

• Macromolecular Research
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• v.16 no.1
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• pp.36-44
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• 2008

A series of polysiloxanes containing alkylsulfonyl side groups were synthesized using a polymer analogous reaction beginning from poly(methylhydrosiloxane) and the corresponding olefins. These polymers showed a mesomorphic behavior with smectic liquid crystalline phases. The chemical and physical properties of these polymers were examined using nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry, optical polarizing microscopy, and X-ray diffraction.

• Elastomers and Composites
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• v.51 no.4
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• pp.269-274
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• 2016

Two different reactive silicone oligomers, hydroxylpropyl terminated PDMS (PDMS-L) and 1-(2,3-dihydroxy-propoxy)propyl terminated PDMS (PDMS-B), were synthesized through hydrosilylation reaction under Karstedt's catalyst. Using the reactive silicone oligomers, two different silicone-modified gel-coat series were prepared to investigate their thermal and mechanical properties as well as surface characteristics according to reactive silicone oligomer contents. In case of thermal stabilities and mechanical properties, the gel-coat series containing PDMS-B showed higher values than that of the gel-coat series containing the PDMS-L. The contact angle for the gel-coat containing both silicone oligomers/was increased with reactive silicone oligomer contents but there was similar surface tension between PDMS-L and PDMS-B.