• Journal of the Korean Wood Science and Technology
• /
• v.45 no.3
• /
• pp.278-287
• /
• 2017

In this study, lignin was efficiently degraded via two-step catalytic cracking process and lignin-oil, char, and gas was produced as lignin degraded products. Three kinds of catalysts (MgO, CaO, and Pt/C) were used in first catalytic cracking step and the highest lignin-oil yield (76.2 wt%) was obtained in Pt/C catalyst with the smallest char formation (4.1 wt%). GC-MS/FID analysis revealed that 18 kinds of monomeric phenols existed in lignin-oil and sum of them was the highest in Pt/C condition (97.8 mg/g lignin). Meanwhile, relatively lower yield of monomeric phenols was produced in MgO and CaO condition because of their absorption on catalysts. Lignin-oil produced over Pt/C was introduced to second catalytic cracking process with porous Pd/activated carbon aerogel catalyst. From this process, four kinds of monomeric phenols such as 4-ethylguaiacol, 4-propylguaiacol, 4-ethylsyringol, 4-propylsyringol were selectively produced at 0.89 - 1.82 wt% level.

• Composites Research
• /
• v.30 no.6
• /
• pp.379-383
• /
• 2017

A study on the low Earth orbit (LEO) space environment have been conducted as a use of composites have increased. Among the LEO environmental factors, atomic oxygen is one of the most critical factors because atomic oxygen can react and erode a surface of polymer-based composite materials. POSS (Polyhedral Oligomeric Silsesquioxane) materials have been widely studied as an atomic oxygen-resistant nanomaterial. In this study, nanocomposites, which are composed of OG (Octaglycidyldimethylsilyl) POSS nanomaterials and DGEBA/DDM epoxy, were fabricated to find out its thermal and mechanical properties. FT-IR results showed that the nanocomposites were fully cured and contained OG POSS enough. Thermogravimetric analysis and differential scanning calorimetry were performed to measure the thermal properties of the nanocomposites. The initial mass loss temperature and char yield were increased through the filling of OG POSS. As the content of OG POSS increased, glass transition temperature tended to increase to 5 wt.% of OG POSS, but the temperature decreased significantly at 10 wt.% of OG POSS. The tensile test results showed that the content of OG POSS did not affect tensile strength and tensile stiffness.

• Elastomers and Composites
• /
• v.40 no.4
• /
• pp.266-271
• /
• 2005

In this work, the thermal stability factors, such as the thermal decomposition temperature, decomposition activation energy ($E_d$), and char yield, were measured to investigate the effect of silicone rubber (SR) content on the thermal stabilities of EPDM/SR blends. As a result, the thermal decomposition curve of EPDM/SR blends was similar to the neat EPDM rubber at 10 wt% SR and the thermal decomposition temperature increased above this content. The $E_d$ value of EPDM rubber initially decreased and then was constant above 20 wt% weight losses. The $E_d$ of EPDM/SR blends was higher than that of the neat EPDM rubber and then decreased with increasing the weight loss when the SR content was in the range of 10-20 wt%. Whereas the $E_d$ of the blends was lower than that of the EPDM rubber and then decreased with increasing the weight loss when 30 wt% SR was added. The char yield at $800^{\circ}C$ increased with increasing the SR content, because the decomposition of silane groups in the backbone was capable of forming a silane-rich residue after the initial stage of thermal degradation, which finally prevents further heat transfer and diffusion in the blends.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.235-238
• /
• 2005

Sulfonated poly(ether sulfone) copolymers (PESs) were synthesized using hydroquinone 2-potassium sulfonate (HPS) with other monomers (bisphenol A and 4-fluorophenyl sulfone). PESs with different $mole\%$ of hydrophilic group were prepared by changing the mole ratio of HPS in the polymerization reaction. The chemical structure and the thermal stability of these polymers were characterized by using $^1H-NMR$, FT-IR and TGA techniques. The PES 60 membrane, which has $60 mole\%$ of HPS unit in the polymer backbone, has a proton conductivity of 0.091 S/cm and good insolubility in boiling water. The TGA showed that PES 60 was stable up to $272^{\circ}C$ with a char yield of about $29\%\;at\;900^{\circ}C\;under\;N_2$ atmosphere. To investigate the single cell performance, the catalyst coated PES 60 membrane was used and a single cell test was carried out using $H_2/O_2$ gases as fuel and oxidant at various temperatures. We observed that the cell performance was enhanced by increasing the cell temperature. A current density of $1400 mA/cm^2$ at 0.60 V was obtained at $70^{\circ}C$.

• Environmental Engineering Research
• /
• v.21 no.2
• /
• pp.180-187
• /
• 2016

In the present work, bael shell (aegle marmelos) is used as the feedstock for pyrolysis, using a fixed bed reactor to investigate the characteristics of the pyrolysis oil. The product yields, e.g., liquid, char and gases are produced from the biomass at different temperatures with the particle size of 0.5-1.0 mm, at the heating rate of $150^{\circ}C/min$. The maximum liquid yield, i.e., 36.23 wt.%, was found at $5500^{\circ}C$. Some physical properties of the pyrolysis oil such as calorific value, viscosity, density, pH, flash point and fire point are evaluated. The calorific value of the bael shell pyrolysis oil was 20.4 MJ/kg, which is slightly higher than the biomass, i.e., 18.24 MJ/kg. The H/C and O/C ratios of the bio-oil were found as 2.3 and 0.56 respectively, which are quite higher than some other bio-oils. Gas Chromatography and Mass Spectroscopy (GC-MS) and Fourier Transform Infra-red (FTIR) analyses showed that the pyrolysis oil of bael shell is mostly composed by phenolic and acidic compounds. The results of the properties of the bael shell pyrolysis oil reveal the potential of the oil as an alternate fuel with the essential upgradation of some properties.

• Fibers and Polymers
• /
• v.2 no.2
• /
• pp.92-97
• /
• 2001

New film forming aromatic poly(amide-imide)s containing isoindoloquinazolinedione (IQ) unit in the backbone chain (polymer XIV) have been successfully synthesized by preparing prepolymers of poly(amic acid-carbonamide). followed by subsequent thermal cyclization of the prepolymers. 4,4-Diamino-3-carbamoylbenzanilide (DACB) V has been synthesized by reduction of 3-carbamoyl-4-amino-4-nitrobenzanilide IV. The prepolymers of poly(amic-acid-carbonamide) (polymers VII and VIII) which exhibit viscosities ranging from 1.4 to 1.7 dl/g have been prepared by a condensation polymerization of monomers such as BPDA, ODA, and DACB. Polymer XIV has been obtained by thermal cyclization of the polymers VII and VIII. During the thermal cyclization reaction, imide ring structure was first introduced and then transformed to the structure of IQ unit. The thermal degradation rate of the resultant polymers were influenced by the cleavage of amide bond but the final char yield was comparable to that of poly(BPDA-ODA).

• 한국연소학회:학술대회논문집
• /
• 2012.04a
• /
• pp.209-212
• /
• 2012

This study was performed to analyze coal flames and measure tar and soot yields and structures of chars for two coals depending on the volatile content by the LFR(Laminar Flow Reactor) which can be applied to a variety of coal researches. The results show that volatile contents and oxygen concentration have significant influence on length and width of the soot cloud and it also indicate that the length and width of the cloud in condition of combustion decrease than those of pyrolysis atmosphere. Until the sampling height reach at 50 mm, the tar and soot yields of Berau (Sub-bituminous) coal contained relatively lots of volatile matters are less than those of Glencore A.P. (Bituminous) coal. On the other hand, tar and soot yields of Berau coal are higher than those of Glencore A.P. coal by reacted residual volatile matter. In addition, the images of samples obtained from the particle separation system of the sampling probe support for above results with the yields, and the pore development of char surface by devolatilization.

• Journal of the Korean Wood Science and Technology
• /
• v.19 no.4
• /
• pp.80-84
• /
• 1991

Lignocellulosic biomass including acetosolv ricestraw and spruce lignin were liquefied and converted into liquid hydrocarbons by catalytic hydroliquefaction reaction. These experimental works were carried out in 1-liter-capacity autoclave using 50% tetralin and m-cresol solution respectively as soluble solvent and Ni. Pd. Fe and red mud as catalyst. $H_2$ gas was supplied into the reactor for escaltion of deoxhydroenolysis reaction. Catalyst concentrations were 1 % of raw material based on weight. The ratio between raw materials and soluble solvent are 1g and 10cc. The reaction conditions are 400-$700^{\circ}C$ of reaction temperature, 10-50 atms of reaction pressure. The highest yield of hydrocarbon, so called "product oil" showed 32% and 5.5% of lowest char formation when red mud was used as catalyst. The product oil yields from those of other catalysts were in the range of 20-29%. The influence of different initial hydrogen pressures was examined in the range d 30-50 atms. A minimum pressure of 35 atms was necessary to obtain a complete recovery of souble solvent for recycling.

• Textile Coloration and Finishing
• /
• v.34 no.1
• /
• pp.1-9
• /
• 2022

The durable FR treatments such Pyrovatex and Proban have been used for cotton fibers, while the finishes involve toxic ammonia or formaldehyde release during finishing process or finished products. In this study, ecofriendly flame-retardant treatment of cotton fabrics was carried out using UV-curable formulations of Vinyl bisphosphonic acid (VBPA), Acrylaminide and Triacryloylhexahydro-1,3,5-triazine, as a monomer, a comonomer and a cross-linking agent respectively, which can introduce a cross-linked copolymer networks. With an optimal finish formulation, the flame retardancy of LOI 29.8 was maintained even after 10 laundering cycles. In TGA analysis, the DTGA peak decreased from 389℃ to 252℃ and the amount of char yield increased from 6.1% to 46.1% compared to the untreated cotton. In addition, MCC analysis showed that Peak HR and THR decreased by 59.4% and 69.2% respectively, compared to the untreated cotton. The pyrolysis and combustion behaviors of the FR-treated cotton implied a condensed-phase flame-retarding mechanism.

• Korean Chemical Engineering Research
• /
• v.43 no.1
• /
• pp.146-152
• /
• 2005

The activated carbon was produced from Sancheong bamboo by carbon dioxide gas activation methods. The carbonization of raw material was conducted at $900^{\circ}C$, and $CO_2$ activation reactions were conducted under various conditions: activation temperatures of $750-900^{\circ}C$, flow rates of carbon dioxide $5-30cm^3/g-char{\cdot}min$, and activation time of 2-5 h. The yield, adsorption capacity of iodine and methylene blue, specific surface area and pore size distribution of the prepared activated carbons were measured. The adsorption capacity of iodine (680.8-1450.1 mg/g) and methylene blue (23.5-220 mg/g) increased with increasing activation temperature and activation time. The adsorption capacity of iodine and methylene blue increased with the $CO_2$ gas quantity in the range of $5-18.9cm^3/g-char{\cdot}min$. But those decreased over those range due to the pore shrinkage. The specific volume of the mesopore and macropore of bamboo activated carbon were $0.65-0.91cm^3/g$. Because of this large specific volume, it can be used to the biological activated carbon process. Bamboo activated carbon phisically adsorbed the $CO_2$ of maximum 106 mg/g-A.C in the condition of 90% $CO_2$ and adsorption temperature of $20^{\circ}C$. The $CO_2$ adsorption ability of bamboo activated carbon was not changed in the 5 cyclic test of desorption and adsorption.