• Journal of the Korean Wood Science and Technology
• /
• v.28 no.1
• /
• pp.36-41
• /
• 2000

This study was carried out to introduce functional groups onto wood by reacting with 2-methacryloyloxyethyl isocyanate(MOI). The effects of the catalyst and the reaction conditions(temperature and time) on the treatment were investigated. The evidence of bonding between wood and MOI were examined by infrared(IR) spectroscopy. The change in surface characteristics of MOI treated wood was examined by water contact angle measurement and X-ray photoelectron spectroscopy(XPS). Wood reacted quickly with MOI in the presence of di-n-butiltin dilaurate catalyst. Especially, the increase in weight percent gain(WPG) with increasing in reaction time was remarkable at the reaction temperature of over $50^{\circ}C$. The IR spectrum of wood reacted with MOI showed a strong urethane absorption(1715 $cm^{-1}$) but no isocyanate(2235 $cm^{-1}$) absorption. It also showed a sharp olefinic C=C double bond absorption at 1635 $cm^{-1}$. This means that an introduced methacrylate group becomes the starting point of further graft copolymerization with another vinyl monomers. The wood modified with MOI showed a gradual increase in contact angle with increasing in WPG, which means that the hydrophilic wood surface become quite hydrophobic. Also, it was cleared that most parts of the wood surface were modified with MOI by XPS analysis.

• Journal of Korean Society for Atmospheric Environment
• /
• v.30 no.6
• /
• pp.577-585
• /
• 2014

A series of experiments using atmospheric-pressure non-thermal plasma coupled with transition metal catalysts were performed to remove ethylene from agricultural storage facilities. The non-thermal plasma was created by dielectric barrier discharge, which was in direct contact with the catalyst pellets. The transition metals such as Ag and $V_2O_5$ were supported on ${\gamma}-Al_2O_3$. The effect of catalyst type, specific input energy (SIE) and oxygen content on the removal of ethylene was examined to understand the behavior of the hybrid plasma-catalytic reactor system. With the other parameters kept constant, the plasma-catalytic activity for the removal of ethylene was in order of $V_2O_5/{\gamma}-Al_2O_3$ > $Ag/{\gamma}-Al_2O_3$ > ${\gamma}-Al_2O_3$ from high to low. Interestingly, the rate of plasma-catalytic ozone generation was in order of $V_2O_5/{\gamma}-Al_2O_3$ > ${\gamma}-Al_2O_3$ > $Ag/{\gamma}-Al_2O_3$, implying that the catalyst activation mechanisms by plasma are different for different catalysts. The results obtained by varying the oxygen content indicated that nitrogen-derived reactive species dominated the removal of ethylene under oxygen-lean condition, while ozone and oxygen atoms were mainly involved in the removal under oxygen-rich condition. When the plasma was coupled with $V_2O_5/{\gamma}-Al_2O_3$, nearly complete removal of ethylene was achieved at oxygen contents higher than 5% by volume (inlet ethylene: 250 ppm; gas flow rate: $1.0Lmin^{-1}$; SIE: ${\sim}355JL^{-1}$).

• Applied Chemistry for Engineering
• /
• v.8 no.5
• /
• pp.804-810
• /
• 1997

A new catalyst system composed of a main catalyst(copper chloride) and promotors of zinc chloride, tin, and cadminum showed excellent performances in the MCS synthesis from silicon and methylchloride. The mixture of catalyst/silicon(5/95), Zn/Cu=0.1, Sn/Cu=0.001, and Cd/Cu=0.001 was mixed in a slurry phase and activated into the contact mass, then it was used for MCS synthesis. The average selectivity was 92% at the silicon consumption of 92% and reaction rate was 175(g-MCS/hr.kg-silicon) at conversion of silicon.

• Journal of Korean Society for Atmospheric Environment
• /
• v.14 no.1
• /
• pp.25-33
• /
• 1998

We have studied the reduction of NO by propane over perovskite-type oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution by substitution of metal into A or B site of perovskite oxides. In addition, the reaction conditions, such as temperature, $O_2$ concentration, space velocity have been studed. In the $LaCoO_3$ type catalyst, the partial substitution of Ba, Sr into A site enhanced the catalytic activity in the reduction of NO. In the $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3(x=0 \sim 1.9)$ catalyst, the partial substitution of Fe into B site enhanced the conversion of NO, but excess amount of Fe decreased the conversion of NO. The surface area and catalytic activity of perovskite catalysts prepared by malic acid method showed higher values than those of solid reaction method. In the $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$ catalyst, the conversion of NO increased with increasing $O_2$ concentration and contact time. The introduction of water into reactant feed decreased the catalytic activity.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.05a
• /
• pp.93-96
• /
• 2001

Structural polymer composites are susceptible to damage in the form of cracks, which form deep within the structure where detection is difficult and repair is almost impossible. A recent methodology for the damage repair of polymer composites using the self-healing technique is reported. The polymerization of the healing agent is triggered by contact with an embedded catalyst, being necessary to damage repair of polymer composites. For this purpose, the self-healing concept is introduced and the manufacturing process of microcapsule with the healing agent is briefly described. The polymerization between the healing agent and the catalyst is verified by the use of ESEM and IR spectroscopy. Finally the efficiency of the self-healing technique is investigated by measuring the critical load of TDCB specimen.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.5
• /
• pp.398-400
• /
• 1995

Selective oxidation of cyclohexane in acetone solution has been studied using iron catalysts with hydrogen peroxide in-situ produced by palladium catalyst. Iron tetraphenylporphyrin chloride shows the highest activity among the tested chlorides and porphyrin complexes of some metals of the first transiton series. Iron chloride and iron tetraphenylporphyrin chloride were supported on four kinds of 4-vinylpyridine copolymer with styrene or divinyl-benzene. Nitrogen 1s photoelectron spectra give the evidence that pyridyl nitrogens of the 4-vinyl pyridine copolymer act as ligands to bind iron species. The copolymer with styrene is the most efficient support for the binding because its solubility in catalyst preparation solvent (methylene chloride) gives the pyridyl group advantage to contact with the iron catalysts. However, better catalytic activity per iron atom could be obtained with a rigid crosslinked polymer due to active site isolation.

• Journal of the Korean Ceramic Society
• /
• v.34 no.12
• /
• pp.1205-1212
• /
• 1997

The matrices which consisted of SiC whisker, PES(polyesterasulfone) as a binder, span 80(sorbitan monooleate) as a surfactant, TPP(triphenyl phosphate) as a plasticizer and dichloromethane as a solvent, have been prepared by the various methods such as tape casting, rolling, tape cast-coating and roll-coating method. The fuel cells of single stack type using these matrices are characterized by ac impedance spectroscopy and cyclic voltammetry technique. A fuel cell using a matrix prepared by the tape cast-coating method shows the best performance of 466.34 mA/$\textrm{cm}^2$ at 0.6V because it has the lowest polarization resistance at the interface between electrodes and a matrix due to the largest three phase contact region of gases, catalyst and electrolyte.

• Elastomers and Composites
• /
• v.55 no.2
• /
• pp.103-107
• /
• 2020

Herein, resin-formed polysilsesquioxanes (PSSQs) were synthesized using monomolecular fluoro silane as a precursor. The synthesized PSSQs exhibited anti-smudge performance and were used as coating liquid. Two structures were acquired by controlling the amount of the silane precursor and the K₂CO₃ catalyst; these materials were used to prepare the anti-smudge coating liquid solution. The synthesized product was analyzed by various methods such as nuclear magnetic resonance spectroscopy, X-ray diffraction analysis, gel permeation chromatography, and water contact angle measurement. The results confirmed that the as-synthesized PSSQs exhibited the ladder structure and had a molecular weight of 5,117 g/mol and water contact angle of 102.31°.

• Korean Chemical Engineering Research
• /
• v.57 no.4
• /
• pp.575-583
• /
• 2019

The results of the catalytic reaction by pulsed injection of reactants are useful for studying the initial reaction characteristics in the case of many coke invloved reactions. The dehydrogenation characteristics of alumina supported platinum tin catalysts were investigated by pulsed injection of propane. The yield of propylene was maximized when the reduction time of propane injection catalyst was $550^{\circ}C$. Raman analysis showed that the amount of coke was very small when PtSn (4.5) catalyst was used and the short contact time was simulated by propane pulse injection. n order to differentiate the degree of dispersion of platinum, PtSn (4.5) catalyst was sintered at $900^{\circ}C$ with hydrogen, and then the temperature of air - redispersion was varied and propane pulse was injected. As a result, conversione and yield were the highest when air-redispersion temperature is $600^{\circ}C$. The lower the air-redispersion temperature, the higher the selectivity. As the tin content in the platinum catalyst increased, the propane conversion was lowered, but the selectivity to propylene increased and the yield increased. From this, it can be seen that the tin-added platinum catalyst is less active than the platinum catalyst from the beginning of the reaction, which is less affected by coke. The dehydrogenation reaction by the propane pulse injection shows a higher conversion rate than the result of continuous injection due to the formation of COx, and the amount of coke is very small. Decrease in selectivity due to the formation of COx can be reduced by increasing the reduction temperature and time.

• Journal of the Korean Vacuum Society
• /
• v.16 no.3
• /
• pp.187-191
• /
• 2007

In this paper, the catalyst layer is deposited on silicon substrate using magnetron sputtering system and carbon nanotubes(CNTs) were grown in $NH_3\;and\; C_2H_2$ gas by hot-filament plasma enhanced chemical vapor deposition (HFPECVD) system. A growth temperature of carbon nanotubes was changed from $350^{\circ}C\;to\;650^{\circ}C\;by\;100^{\circ}C$. We observed the shape of CNTs by a field-emission scanning electron microscope(FE-SEM) measurement and analyzed the surface characteristic of CNTs layer by contact angle measurement. That is, the growth temperature of CNTs is the important factor leads to the variation of the properties.