• Macromolecular Research
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• v.15 no.6
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• pp.565-574
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• 2007

In this study, five representative, commercially available polymers, Ultem 1000 polyetherimide, Kapton polyimide, phenolic resin, polyacrylonitrile and cellulose acetate, were used to prepare pyrolyzed polymer membranes coated on a porous {\alpha}-alumina$ tube via inert pyrolysis for gas separation. Pyrolysis conditions (i.e., final temperature and thermal dwell time) of each polymer were determined using a thermogravimetric method coupled with real-time mass spectroscopy. The surface area and pore size distribution of the pyrolyzed materials derived from the polymers were estimated from the nitrogen adsorption/desorption isotherms. Pyrolyzed membranes from polymer precursors exhibited type I sorption behavior except cellulose acetate (type IV). The gas permeation of the carbon/{\alpha}-alumina$ tubular membranes was characterized using four gases: helium, carbon dioxide, oxygen and nitrogen. The polyetherimide, polyimide, and phenolic resin pyrolyzed polymer membranes showed typical molecular sieving gas permeation behavior, while membranes from polyacrylonitrile and cellulose acetate exhibited intermediate behavior between Knudsen diffusion and molecular sieving. Pyrolyzed membranes with molecular sieving behavior (e.g., polyetherimide, polyimide, and phenolic resin) had a $CO_2/N_2$ selectivity of greater than 15; however, the membranes from polyacrylonitrile and cellulose acetate with intermediate gas transport behavior had a selectivity slightly greater than unity due to their large pore size.

• Journal of the Korean Chemical Society
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• v.7 no.2
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• pp.115-121
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• 1963

Aliphatic hydrocarbon gases from rubber pyrolysis have been identified by gas chromatography with tetraethyleneglycol dimethylether column. Rubbers used in this work are polyisoprene, SBR, NBR, polybutadiene, buthyl rubber, polychloroprene and polyurethane rubber. The chromatogram is characteristic for each polymer. Author proposes a method of identification of synthetic rubbers by gas chromatograph of pyrolyzed gas. Sample is pyrolyzed at $450^{\circ}C$ under nitrogen or more effectively helium and gaseous portion, which eliminated liquid condensate, is passed to the column. The appearance of exclusively large peak of isoprene, isobutylene and carbon dioxide shows the presence of polyisoprene, polyisobutylene and polyurethane, respectively. Large peak of butadiene will appear in case of polybutadiene, SBR and NBR, but SBR can be identified through the styrene peak in gas chromatogram of liquid pyrolyzate and NBR can be identified by the evolution of hydrogen cyanide during pyrolysis. Polychloroprene is identified by the evolution of hydrogen chloride. This method could be applied to the identification of copolymer or polymer blend.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.222-222
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• 2011

Plastic product is increasing by the growth of its demand and most of refused plastics are incinerated or reclaimed. However, the refused plastic is not easily decomposed and has the environmental problem with its various toxic gas in case of incineration. Therefore, many countries such as USA, Japan, Germany and other developed industrial countries as well as Korea are interested in studying the recyclable resource of refused plastic. The macromolecular waste pyrolysis has the advantage of collecting of raw materials in high price and can at least get fuel gas or oil with high heat capacity. It also discharges low waste gas and low toxic gas including SOx, NOx and HCl heavy metals. However, pyrolyzed oil includes enough excess unsaturated hydrocarbons to form tar, which can cause the nozzle of engines to plug when pyrolyzed oil is used as fuel. Activated carbon was proven to have prominent adsorption capability among the other adsorbents that were mainly composed of carbon. This study examined the possibility of application in activated charcoal of its solid formation by analysing the feature of pyrolysis which is one of the chemical recycling methods and getting chemical analysis of the product and activated energy. Analyze the element of the oil produced by pyrolysis using GC-MS. The experiment of tar adsorption using fly-ash showed that fly-ash improved the optical intensity of pyrolyzed oil and decreased oxygen compounds in the pyrolyzed oil.

• Elastomers and Composites
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• v.55 no.4
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• pp.257-262
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• 2020

Vehicle wiper blades are typically treated with chlorine to lower their friction coefficient with the windshield surface. In this study, a chlorinated, natural rubber (NR) vehicle wiper blade was characterized using a pyrolytic technique. Unchlorinated and chlorinated wiper blades were pyrolyzed and the pyrolysis products were analyzed using gas chromatography/mass spectrometry (GC/MS). Besides isoprene and dipentene, the other principal pyrolysis products such as 1,5,8-p-menthatriene (MTT) and p,α-dimethylstyrene (DMS) were observed. The MTT and DMS ratios did not vary for the chlorinated nor unchlorinated samples when the entire rubber lip of the wiper blade was pyrolyzed. However, when only the lip surface of the wiper blade rubber was pyrolyzed (via scratching with a knife) the relative ratios of the chlorinated sample were much greater than those of the unchlorinated sample. As MTT is produced from the conjugated backbone of chlorinated NR that forms through HCl elimination during initial pyrolysis, and DMS is generated by the dehydrogenation of MTT, these two products could be used as markers for detecting chlorinated NR.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.618-622
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• 2007

This paper provides RPF (Refuse Plastics Fuel) gasification characteristics for generating synthesis gas in gasfying reactor which was design in lab-scale. This research is carried out as an immediate work for making pyrolysis gas from RPF into energy resource. This study is consisted of experimental and numerical. The numerical study was accomplished from RPF pyrolysis data, and predicted the maximum operating conditions by STANJAN and FLEUNT. Based on results of STANJAN, it is found that the maximum point of $O_2/O_{2,stoich}$=20${\sim}$30, which is used as injection point of $O_2$. Experiment results shows that CO and $H_2$ were increased but THC was decreased as temperature was increased. It is estimated that the cracking of cracking of THC into CO and H2 is happened at a high temperature. It is observed that as steam was injected, production of CO and H2 were increased, then, H2 is dependent on the amount of injectionsteam.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1099-1103
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• 1999

The surface of an ${\alpha}$-alumina tube was coated with zirconium modified polycarbosilane(PZC) by dip-coating method. Then the tube was pyrolyzed at 573~823 K. The prepared inorganic composite membrane was in $1{\mu}m$ thickness and had no pinholes larger than several nm. For the pyrolyzed inorganic composite membrane, the permeation test of He, $N_2$, $CO_2$, and $O_2$ was performed at 303~423 K. The gas permeation and separation factor were increased with increasing permeation temperature. The permeation for gases was controlled by the activated diffusion mechanism. The separation factor of $CO_2$, to $N_2$was 4.9 at 363 K on the composite membrane pyrolyzed at 823 K and its value was higher than that of He and $O_2$.

• Elastomers and Composites
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• v.51 no.1
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• pp.63-67
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• 2016

Poly(ethylene-co-vinyl acetate) (EVA) was pyrolyzed to eliminate acetic acid of VA unit using off-line pyrolysis, and the deacetylated EVA was analyzed infrared spectroscopy (IR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). EVA film for deacetylation was prepared by solution casting on aluminum foil and it was pyrolyzed at low temperature of $300^{\circ}C$ in the off-line pyrolysis apparatus. After deacetylation, carbon-carbon double bond (C=C) was formed by 1,2-elimination of the VA unit in the EVA backbone. Most of C=C bonds were trans-1,4-unit and 1,2-unit was also observed. Presence of the 1,2-unit in deacetylated EVA indicates that terminal or branch VA units exist in the raw EVA. Py-GC/MS chromatogram of deacetylated EVA displayed much smaller acetic acid and much more abundant other pyrolysis products than that of raw EVA, which means that the pyrolysis efficiency and separation condition were improved.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.495-500
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• 2011

Separation of naphthalene from pyrolyzed fuel oil, by product of Naphta cracking process (NCC) process, has been accomplished by the solvent extraction, distillation and purification process. The residual pyrolyzed fuel oil (PFO), called precursor of carbon materials, has been calcined at $300{\sim}800^{\circ}C$ in nitrogen gas to raw pitch. After the treatment of PFO by hexane and methanol, either a flake phased carbon at $350^{\circ}C$ or a carbon sphere at above $400^{\circ}C$ forms. As the calcination temperature increases, the shape of raw pitch changes from the flake phase to the sphere one, and the size of them decreases to several ${\mu}m$. Based on the BET and XRD spectrum, the carbon sphere is classified to a mesophase amorphous carbon with a cubic phase.

• Journal of the Korean Society of Combustion
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• v.10 no.1
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• pp.27-36
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• 2005

In this study, we investigated characteristics of a gas flow and a combustion property during the combustion of a RDF in a pyrolysis melting incinerator with disposal rate of 30 kg/hr. The RDF was pyrolyzed through the pyrolysis chamber at $600^{\circ}C$ of the chamber surface without oxygen condition. The pyrolysis gas was injected in the combustion chamber. It was burned by means of the staged combustion that was injecting secondary and tertiary air in the combustor. We measured the temperatures and the gas components in the combustion chamber while maintaining the air-fuel ratio of 1.3. Finally, we confirm that additional air injection, secondary and tertiary air ratio, was the most important factor to reduce NOx.

• Carbon letters
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• v.27
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• pp.35-41
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• 2018

Surfactant-wrapped separation methods of metallic and semiconducting single-walled carbon nanotubes (SWCNTs) can result in large changes in intrinsic physical and chemical properties due to electronic interactions between a nanotube and a surfactant. Our approach to synthesize SWCNTs with an electronic feature relied on utilizing carbon nanorings, [n] cycloparaphenylenes ([n]CPPs), which are the fundamental unit of armchair type SWCNTs (a-SWCNTs) that possess a metallic feature without any surfactants. To obtain long tubular structures from [n]CPPs, the host-guest complexes formed with well-aligned [n]CPP hosts and various fullerene guests on a silicon substrate were pyrolyzed under an ethanol gas flow at a high temperature with focused-ultraviolet laser irradiation. The pyrolyzed [n]CPPs were observed to transform from nanorings to tubular structures with 1.5-1.7 nm diameters corresponding to the employed diameter of [n]CPPs. Our approach suggests that [n]CPPs are useful for structure-controlled synthesis of SWCNTs.