• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1061-1068
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• 1996

The conducting polymer composites were prepared by imbibing the porous particle wish the $FeCl_3$ oxidant solution, drying the imbibed porous particle, and imbibing again with pyrrole solution for polymerization to take place in the pore of porous particles. The effect of synthesis conditions on the conductivity of composite polymers were investigated. It was found that the conductivity of composite polymers was dependant on the concentration of pyrrole monomer, nature of the oxidants and solvents used for the oxidant and pyrrole, which influence the degree of penetration/distribution of polyprrole in the composite and reaction of dopant with pyrrole.

• Journal of Integrative Natural Science
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• v.7 no.4
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• pp.266-272
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• 2014

Oxocane high explosives substituted to explosive group such as azide (-CH2N3), nitrate (-CH2ONO2), and hydrazine (-CH2N2H3) are investigated theoretically the acid catalyzed reaction using the semiempirical MINDO/3, MNDO and AM1 methods to use as the guidelines of high explosives. The nucleophilicity and basicity of oxocane high explosives can be explained by the value of negative charge on oxygen atom of oxocane and the reactivity in propagation step can be represented by the value of positive charge on carbon atom and low electrophile LUMO energy. It was known that carbenium ion was favorable due to the stable energy (11.745~25.461 Kcal/mol) between oxonium ion and carbenium ion in the process of cyclic oxonium ion of oxocane high explosives being converted to open carbenium ion in oxocane high explosives. The value of concentration of cyclic oxonium ion and open carbenium ion in equilibrium status was found to be a major determinant of mechanism, it was expected to react faster in the prepolymer propagation step in SN1 mechanism than in that of SN2.

• Journal of the Korean Chemical Society
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• v.20 no.5
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• pp.424-430
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• 1976

Isocyanate-terminated SBR-prepolymers were prepared from SBR-diol and excess toluene diisocyanate. These prepolymers were then used as initiators for the sodium-catalyzed polymerization of ${\varepsilon}$-caprolactam. The resulting block copolymers, presumably the structure of nylon 6-SBR-nylon 6, were confirmed from their IR spectra. The viscosities of these polymers were measured in phenol/tetrachloroethane and the molecular weights were estimated. The polymerization reaction was not affected by the change in concentration of catalyst, but significantly faster at $185^{\circ}C$ than at $150^{\circ}C$. And the initiator concentration of 0.5 mole % gave good results.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.252-256
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• 2007

A series of spherical porous carbons were prepared via resorcinol-formaldehyde (RF) sol-gel polymerization in the presence of cationic surfactant (CTAB, cetyltrimethylammonium bromide), wherein the carbon sphere size was controlled by varying the CTAB introduction time after a pre-determined period of addition reaction (termed as "pre-curing"). The sphere size gradually decreases with an increase in the pre-curing time within the range of 30-150 nm. The carbons possess two types of pores; one inside carbon spheres (intra-particle pores) and the other at the interstitial sites made by carbon spheres (inter-particle pores). Of the two, the surface exposed on the former was dominant to determine the electric double-layer capacitor (EDLC) performance of porous carbons. As the intra-particle pores were generated inside RF gel spheres by gasification, the pore diameter was similar for all these carbons, thereby the pore length turned out to be a decisive factor controlling the EDLC performance. The charge-discharge voltage profiles and complex capacitance analysis consistently illustrate that the smaller-sized RF carbons deliver a better rate capability, which must be the direct result of facilitated ion penetration into shorter pores.

• Journal of Adhesion and Interface
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• v.12 no.1
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• pp.1-10
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• 2011

An automated reaction calorimeter was used to directly monitor the rate of emulsion polymerization of vinyl acetate using poly(vinyl alcohol) (PVAs) having different degrees of blockiness. By using this technique in conjunction with other off-line measurements of the evolution of particle size distributions, important details of the process were observed. No constant graft rate period was observed for both low and high initial monomer-water ratios. The gel effect was observed for the low monomer-water ratio recipe. The particle size distributions were broad (particle diameter 40~100 nm) and bimodal. Continuous nucleation was observed to be accompanied by 'limited aggregation' and flocculation during the particle growth stages. It was speculated to be due to the occurrence of the extensive 'limited aggregation' and chain transfer to PVA leading to grafting.

• Macromolecular Research
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• v.12 no.1
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• pp.107-111
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• 2004

We have studied the polymerization kinetics of acrylamide in aqueous solution with potassium persulfate as an initiator by using quantitative real-time in situ IR spectroscopy and monitoring the profiles of peaks in the range 1900-850 cm$\^$-1/. The conversion of acrylamide was calculated from the disappearance of the peak at 988 cm$\^$-1/, which is the out-of-plane bending mode of the=C-H unit, normalized to the C=O stretching peak at 1675 cm$\^$-1/, as an internal standard. For reaction temperatures in the range 40-65$^{\circ}C$ and initiator and monomer concentrations of 0.9-2.6 mmol/L and 0.5-1.1 mol/L, respectively, we deduced that the rate of monomer consumption follows the relation R$\_$p/=k［K$_2$S$_2$O$\_$8/］$\^$0.5/ [Μ］$\^$1.35${\pm}$0.10/. In addition, we obtained activation parameters from an evaluation of the kinetic data.

• Journal of Adhesion and Interface
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• v.13 no.2
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• pp.53-57
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• 2012

A latent curing system was necessary for the anisotropic conducting film (ACF), and a fast reaction system was also necessary to fast production. In this study, the benzylsulfonium salts were synthesized and were used as latent curing initiators for epoxy resin. These benzylsulfonium compounds exhibited a long shelf life with epoxy resin. The curing behaviors of an epoxy resin with these sulfonium salts were investigated using differential scanning calorimetry (DSC), and the curing times were determined at $150^{\circ}C$ using an indentation method.

• Macromolecular Research
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• v.16 no.2
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• pp.103-107
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• 2008

Carbon nanodots were prepared by the pyrolysis of a triblock copolymer. The triblock copolymer, poly(methyl methacrylate)-b-polystyrene-b-poly(methyl methacrylate) was synthesized by atom transfer radical polymerization using an initiator containing a diacetylene group. A polymer thin film on a mica substrate was prepared by spin-casting at 2,000 rpm from a 0.5 wt% toluene solution of the triblock copolymer. After drying, the cast film was vacuum-annealed for 48 h at $160^{\circ}C$. The annealed film formed a spherical morphology of polystyrene domains with a diameter of approximately 30 nm. The film was exposed to UV irradiation to induce a cross-linking reaction between diacetylene groups. In the subsequent pyrolysis at $800^{\circ}C$, the cross-linked polystyrene spheres were carbonized and the poly(methyl methacrylate) matrix was eliminated, resulting in carbon nanodots deposited on a substrate with a diameter of approximately 5 mn.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.726-728
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• 1998

Oil-impregnated nylons were synthesized by anionic polymerization of ${\varepsilon}$-caprolactam in the presence of mineral oils. Reaction rate and molecular weight of the product were not significantly affected by the addition of oils less than 8 phr. Physical properties such as elongation and notched impact strength were improved by the addition of oil, on the other hand hardness and tensile stress at break were slightly decreased. Oil-impregnated nylon with an oil content of 6 phr showed a minimum friction coefficient, which is only 32% compared to a friction coefficient of nylon 6 without oil.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.231-236
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• 2008

The well-defined copolymers derived from Epichlorohydrin(ECH), Tetrahydrofuran(THF) were synthesized by Cationic ring-opening polymerization(CROP) with 1,4-Butandiol, a initiator, and $BF_3THF$ Complex, a catalyst via Activated monomer mechanism, which could lead to hydroxyl-terminated polyethers. The molecular weight of polymers were dependant on the ratio of [monomer]/[diol], Copolymer structures were controlled by monomers feed ratio, ECH and THF added. This polymers were functionalized from Chlorine group to Azide group using $S_N2$ reaction. Synthesized polymers were found to be as the prepolymer for polyurethane. Polyurethane was synthesized in the presence of N-100/IPDI mixture, a curing agent, and TPB(triphenyl bismuth)/MA(Maleic anhydride) mixture, a catalyst system. The curing behavior and mechanical properties of polyurethane after mixing with various prepolymer’s composition and the molecular weight were studied.