• Textile Coloration and Finishing
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• v.8 no.3
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• pp.31-35
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• 1996

Modal fabric was pretreated with sodium hydroxide, sodium persulfate, and their combined mixture by pad-steaming procedure. The tearing strength of the pretreated modal fabric was measured for subsequent microfibrillation. The solubility of modal fiber in sodium hydroxide solution was highest at 10 % concentration of sodium hydroxide. Extended steaming of the modal fabric padded with 6% sodium hydroxide solution did not reduce the tearing strength appreciably. 2% sodium persulfate pretreatment greatly reduced the tearing strength of modal fabric within 7 minutes of steaming time. The pretreatment with combined composition of sodium hydroxide and sodium persulfate brought about stable reduction in tearing strength within 1 minute of steaming time, which would be appricable to the continuous pretreatment of modal fabric for microfibrillation. Microfibrillation behavior of the pretreated modal fabric was tested also.

• Journal of the Korean Society of Clothing and Textiles
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• v.12 no.2 s.27
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• pp.181-188
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• 1988

Cotton fabrics were slack-mercerized in sodium hydroxide, ammonia water(min. $28{\%}\;NH_3$), and mixture of ammonia water/sodium hydroxide. The surface of treated cotton fabrics were observed through SEM, and the changes of fine structure were analyzed by X-ray diffractometer. In addition to that shrinkage was compared mutally, and tenacity-elongation compared, too. SEM photographs showed fibrls rearranged strightly toward fibre axis. X-ray diffraction represented increased amorphous fraction, and partial recrystallization into cellulose 2 lattic after treatment with sodium hydroxide and mixture of ammonia water/sodium hydroxide. The mercerization produced increased fibre tenacity-elongation with slark state. Lastly, the best condition of mercerization was $4\%/14\%$, $10^{\circ}C,\;5\~30$ min. in mixture of ammonia/sodium hydroxide.

• Journal of the Korean Wood Science and Technology
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• v.38 no.2
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• pp.149-158
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• 2010

Organosolv pretreatments which utilized sulfuric acid, sodium hydroxide and ammonia as catalysts were conducted to screen the effective catalyst for organosolv pretreatment of Liriodendron tulipifera. The enzymatic hydrolysis was achieved effectively with sulfuric acid (74.2%) and sodium hydroxide (63.7%). They were thus considered as effective catalysts for organosolv pretreatment of L. tulipifera. The organosolv pretreatments with sulfuric acid and sodium hydroxide showed a different behavior on the reaction mechanism. The pretreatment with sulfuric acid increased the biomass roughness and pore numbers. On the other hand, the pretreatment with sodium hydroxide enhanced the surface area due to the size reduction and minor defiberization which were caused by hemicellulose degradation at an initial stage and more defiberization by lignin degradation at a later stage. The organosolv pretreatment with sodium hydroxide was performed at several different conditions to evaluate effectiveness of sodium hydroxide as a catalyst for organosolv pretreatment. According to the results of enzymatic digestibility, the changes of chemical composition and the morphological analysis of pretreated biomass, it was suggested that the pretreatment time impacted primarily on enzymatic hydrolysis. Increase in surface area during the pretreatment was a major cause for improvement in enzymatic digestibility when sodium hydroxide was used as a catalyst.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.4
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• pp.18-27
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• 1997

This study was performed to obtained the optimal delignified condition of exploded wood on the acid hydrolysis with sulfuric acid. Wood chips of pine wood(Pinus desiflora), oak wood(Quercus serrata) and birch wood (Betula platyphylla var. japonica) were treated with a high pressure steam (20-30kgf/$\textrm{cm}^2$, 2-6 minutes). The exploded wood was delignified with sodium hydroxide and sodium chlorite, and then hydrolyzed with sulfuric acid. The result can be summerized as follows ; In the exploded wood treated with sodium hydroxide, the optimal concentration of sodium hydroxide was 1% as content of lignin in the exploded wood. Lignin content of exploded wood treated with sodium chlorite was lower then that sodium hydroxide. The maximum reducing sugar yield of exploded wood treated with 1% sodium hydroxide was lower than non-treated exploded wood. In the case of sodium chlorite treated, the maximum reducing sugar yield was hgher than non-treated exploded wood. Sugar composition of acid hydrolysis solution was composed of xylose and glucose residue, and the rate of glucose residue was increased in high pressure condition.

• Environmental Engineering Research
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• v.21 no.3
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• pp.297-303
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• 2016

Global warming due to greenhouse gases is an issue of great concern today. Fossil fuel power plants, especially coal-fired thermal power plants, are a major source of carbon dioxide emission. In this work, carbon capture and utilization using sodium hydroxide was studied experimentally. Application for flue gas of a coal-fired power plant is considered. Carbon dioxide, reacting with an aqueous solution of sodium hydroxide, could be converted to sodium bicarbonate ($NaHCO_3$). A bench-scale unit of a reactor system was designed for this experiment. The capture scale of the reactor system was 2 kg of carbon dioxide per day. The detailed operational condition could be determined. The purity of produced sodium bicarbonate was above 97% and the absorption rate of $CO_2$ was above 95% through the experiment using this reactor system. The results obtained in this experiment contain useful information for the construction and operation of a commercial-scale plant. Through this experiment, the possibility of carbon capture for coal power plants using sodium hydroxide could be confirmed.

• Textile Coloration and Finishing
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• v.21 no.4
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• pp.23-32
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• 2009

The objective of this study is to investigate the efficacy of leaf powder colorants as substitutes for traditional indigo dyeing. Leaf powder colorants were prepared by hot air($50^{\circ}C$) and room temperanrre($25^{\circ}C$) drying methods from fresh leaves. The presence of indigo in the leaf powder colorants was confirmed by UV/Visible absorption spectra. All the powder colorants showed broad absorption at 602 nm as same as synthetic indigo. Dyeing was done by reduction method with sodium hydrosulfite and sodium hydroxide. Leaf powder colorants produced blue color on silk fabrics, showing similar color to the one dyed traditionally with fresh juice extract. The powder colorants prepared at room temperature drying were more stable for long term storage than that prepared by hot air drying. Thus, the powder colorants prepared by room temperature drying was reduced and dyed in one-step process without sodium hydroxide in the dyebath for further investigate dyeing properties. K/S value of the fabric dyed without sodium hydroxide was much higher than one dyed with sodium hydroxide. Regardless of the addition of sodium hydroxide, rubbing fastness was fairly good showing above 4 rating. Fastness to dry cleaning and light of the fabrics dyed without sodium hydroxide were mote higher than that dyed in alkaline condition.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.4
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• pp.334-341
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• 1998

Sodium hydroxide concentrations were adjusted to 2.0, 2.5, 3.0 and 3.5M by dissolution in seawater. The fly ash was hydrothermally reacted with sodium hydroxide solutions (1:8, W:V) at $100^{\circ}C$ under the closed system. X-ray diffractogram proved that Na-P1 type zeolite was produced from bituminous coal fly ash. It is different from the X-ray of artificial zeolite produced by using sodium hydroxide solution dissolving in distilled water. Solid sieve structure was developed well by hydrothermal reaction with the ash and 3.0M sodium hydroxide. However chinks were observed in the structure of the product by 3.5M sodium hydroxide. CEC of the artificial zeolite was $244.5cmol^+\;kg^{-1}$ at 2.0M, 259.8 at 3.0M, 263.4 at 3.0M and 179.8 at 3.5M after 24 hours hydrothermal reaction; Artificial zeolite having high CEC, above $244.5cmol^+\;kg^{-1}$ could produce by using lower concentration of NaOH prepared in seawater than other production methods.

• Textile Coloration and Finishing
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• v.12 no.6
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• pp.380-388
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• 2000

The porosity of polyester fibers treated with sodium hydroxide aqueous solution was investigated using a nitrogen porosimeter, and the dyeability of the treated fibers was discussed in terms of the porosity. In pore distribution, the polyester fibers treated with sodium hydroxide aqueous solution were characterized by higher amount of pores below $10\AA$ than those of the untreated fibers, and by shift of the pore size having maximum accumulated volume from $10\AA$ for the untreated fibers to $5~6\AA$. As the weight loss of the polyester fibers treated with sodium hydroxide aqueous solution increased, BET surface area and total pore volume increased linearly, but average pore size, showing some different aspect, increased steeply at earlier stage and then approached the maximum value. The dye uptakes of the polyester fibers treated with sodium hydroxide aqueous solution increased with the BET surface area, the total pore volume and the average pore size. The alkali treatment increased the surface area of polyester fibers, so that the chance of contact between the fiber and dye molecules increased. In addition, the pores created on the surface of polyester fibers by alkali treatment might act as pathways for dye molecules into the polyester fibers.

• Journal of the Korean Society of Clothing and Textiles
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• v.11 no.1
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• pp.63-69
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• 1987

Silk fibroin is likely to be hydrolyzed by acids or alkalies at high temperature, and the degree of the hydrolysis has been inferred from the changes in tensile strength and elongation. But, in this experiment, it was intended to infer that from the quantitative changes in terminal aminp group content as well as in tensile strength and elongation. Silk yarn was treated with boiling water, hydrochloric acid, and sodium hydroxide under various conditions. The boiling water somewhat degraded silk fibroin. Silk yarn treated with sodium hydroxide contained more terminal amino group than that treated with hydrochloric acid. This result agreed fairly well with the loss in weight, tensile strength, and elongation: the terminal amino group content increased with the decrease of tensile strength, elongation, and weight. The damage by sodium hydroxide to the silk fibroin was greater than that by hydrochloric acid.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.3
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• pp.155-160
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• 2000

This syudy was conducted to increase the utility of forage rye which are suitable to be cultivated at high altitude Taekwllyong area. For that purpose two cultivars of rye (winter-more, kool-glazer) were cultivated for 3years using a randomized block design with 3 replications. The dry matter digestibility (DMD) was evaluated with the pelleted rye hay produced by adding sodium hydroxide and then the TDN value was calculated by the DMD. By adding NaOH, DMD and TDN value of rye pellets (Y=46.92+ 1.8X, ~ 0 . 9 7 )w ere increased significantly (p<0.05) and NDF (neutral detergent fiber) decrease significantly. However, ADF (acid detergent fiber) and lignin did not significantly decrease (p<0.05). Rye could be cultivated as a second crop after com at high altitude area in the same year and pelleted with NaOH in order to increase the nutritive values (p< 0.05). (Key words : Dry matter digestibility (DMD), Forage rye, NDF, ADF, Sodium hydroxide)