• Polymer(Korea)
• /
• v.38 no.3
• /
• pp.397-405
• /
• 2014

To manufacture of high-performance semi-structural double-sided adhesive tape, 2-ethylhexyl acrylate (2-EHA) and acrylic acid (AAC) were used, and the syrup was prepared by UV irradiation in this study. The effects of the thickness, various inorganic filler contents, and filler types on the semi-structural properties of acrylic double-sided adhesive tape were investigated. The peel strength increased with increasing thickness and wetting time. In case of the thin thickness (under $250{\mu}m$) with decreasing true density of inorganic filler, the peel strength increased with increasing wetting time. The initial peel strength showed a higher value at a big size of inorganic filler, and the filler's size in adhesive tapes was confirmed by SEM images. The peel strength and dynamic shear strength increased as a proportional relationship with various inorganic fillers and contents, and these inorganic fillers in $0.1{\mu}m$ thickness indicated more effect on the dynamic shear strength of double-sided adhesive tape. From these results the thin acrylic double-sided adhesive tape determined to be use for applications as a high-performance semi-structural.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.35 no.2
• /
• pp.72-80
• /
• 2019

Purpose: The purpose of this study is to compare and analyze the shear bond strength and fracture pattern in different enamel tooth surface treatments for resin splinting materials. Materials and Methods: G-FIX and LightFix were used as tooth splinting materials. Twenty bovine mandibular incisors were used for the preparation of the specimens. The exposed enamel surface was separated into four parts. Each tooth was treated with 37% phosphoric acid, 37% phosphoric acid + adhesive resin, 37% phosphoric acid + G-premio bond, and G-premio bond for each fraction. Shear bond strength was measured using a universal testing machine. After measuring the shear bond strength, the fractured surface of the specimen was magnified with a microscope to observe the fracture pattern. Two-way ANOVA was used to verify the interaction between the material and the surface treatment method. One-way ANOVA was used for comparison between the surface treatment methods of each material and post-hoc test was conducted with Scheffe's test. An independent t-test was conducted to compare shear bond strengths between materials in each surface treatment method. All statistics were conducted at 95% significance level. Results: G-FIX, a tooth splinting resin, showed similar shear bonding strength when additional adhesive resins were used when material was applied after only acid etching, and LightFix showed the highest shear bonding strength when additional adhesive resins were used after the acid etching. In addition, both G-FIX and LightFix showed the lowest shear bond strength when only self-etching adhesive was applied without additional acid etching. Verification of interactions observed interconnection between resins and surface treatment methods. Most of the mixed failure was observed in all counties. Conclusion: When using G-FIX and LightFix, which are tooth-splinting materials, it is considered that sufficient adhesion will be achieved even after applying only acid etching as instructed by the manufacturer.

• Textile Coloration and Finishing
• /
• v.12 no.1
• /
• pp.44-51
• /
• 2000

The conventional one bath exhaust dyeing system of nylon]/cotton blends with acid dye/direct dye involves a lot of neutral salt which affect dyeability of acid dyes. Because of conventional one bath exhaust dyeing system of nylonl/cotton blends with acid dye/direct dye needs acid dyes adjusted at a neutral liquor, suitable acid dye is limited. To improve dyeing property of nylon/cotton blends, cotton component was pretreated with cationizing agent containing chlorohydrine group in aqueous solution of sodium hydroxide. This study was carried out to investigate dyeing possibilities of nylon/cationized cotton blends with acid dye/direct dye in a non-neutral salt dyebath by one bath two step method. The concentration of direct dye was 1.0%, 0.7%, 0.3%o.w.f. respectively at a non, 1%, 3%owf of reserving agent for being almost equal color strength between nylon and 3% cationized cotton when nylon/3% cationized cotton blends was dyed with acid dye/direct dye at concentration of acid dye(1%o.w.f.) by one bath two step method.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.33 no.5
• /
• pp.30-36
• /
• 2001

Caro's acid (persulphuric acid) has been proposed as a promising reagent used in pulping of lignocellu-losic materials. Bagass was subjected to caro's acid pulping under different pulping conditions of per acid concentration (2~8 percent), pulping temperatures (40~$60^{\circ}C$) and pulping time (120~240 min). The influence of different parameters of caro's acid pulping process on the chemical and strength properties of the produced pulps had been studied. Peracid concentration and pulping temperature are the most important variables of the pulping process. High degree of delignification and good deliberation were achieved at moderate pulping conditions in the studied range. Pulping experiments of bagasse by using caro's acid had been carried out for determination of the optimum comditions of the process. In inch case to effectively tackle the problem, a specific design of an experiment is selected depending on the goals to be achieved in the experimentation. The study could enable us to excepect the bagasse pulp properties (yield, Kappa number, DP) that be stated as function of the independent variables of caro's acid pulping process (per acid concentration, pulping temperature and pulping time).

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2015.10a
• /
• pp.465-466
• /
• 2015

In this study, different amount of (fe(0)) were dissolve into different strength of phosphoric ($H_3PO_4$) acid and the optimum solubility was observed at 0.89M Fe(0) into 4M of $H_3PO_4$ acid. Different concentration of oxalic acid was added to determine the optimum precipitated condition. The dissolution kinetics of Fe(0) into $H_3PO_4$ acid was investigated at $40-50^{\circ}C$. The optimum Fe-oxalate precipitate was dried and thermal decomposition using DSC-TG was conducted. Approximately 52 wt(%) of oxalic acid was removed at $300^{\circ}C$. Iron oxides such as magnetite and hematite that may be formed on the surface of nuclear waste were also dissolved into the $H_3PO_4$ acid and the optimum solubility for magnetite is 0.005M while that for hematite is 0.02M in 8M $H_3PO_4$ acid, respectively.

• Journal of the Korean Applied Science and Technology
• /
• v.3 no.2
• /
• pp.29-34
• /
• 1986

The sulfuric acid sulfonation of 2-aminonaphthalene was preformed at $30^{\circ}C{\sim}200^{\circ}C$ for $1{\sim}15$ hours, using $4{\sim}10$ parts of 90% sulfuric acid${\sim}$20% oleum. This reaction was influenced by many factory such as reaction temperature, reaction time, strength of sulfuric acid and amount of sulfuric acid and among these factors, the effect of the reaction temperature was considerable. The main products of this reaction were Dahl's acid (2-aminonaphthalene-5-sulfonic acid, Broenner's-acid (2-aminonaphthalene-6-sulfonic acid), amnio-F-acid(2-aminonapthalene-7-sulfonic acid), and Baden acid (2-aminonaphthalene-7-sulfonic acid) and another isomers such as Tobia's acid (2-aminonaphthalene-1-sulfonic acid) and 2-aminonaphthalene-4-sulfonic acid were not formed. Of these isomeric acids, those containing the sulfonic acid group in an ${\alpha}-position$, namely, Dahl's acid and Baden acid, are simultaneously formed by sulfonation at low-temperature ($30{\sim}100^{\circ}C$), whilst those containing the sulfonic acid group in a ${\beta}$-position, namely, Broenner's acid and amino-F-acid, are formed simultaneously by sulfonation at high temperatures($150^{\circ}{\sim}200^{\circ}$).

• Restorative Dentistry and Endodontics
• /
• v.18 no.1
• /
• pp.73-83
• /
• 1993

The purpose of this study was to evaluate the effect of various acid treatments on dentin bonding. Freshly extracted human teeth were uprightly embedded in self curing acrylic resin, and their occlusal surfaces were grinded to expose flat dentin surfaces. The specimens were divided into 4 groups. Specimens of one group were not treated so as to be a control and those of the other three groups were threated with 10% polyacrylic acid, 10% phosphoric acid, and 10-3 solution(10% citric acid/3% ferric chloride) respectively. Primer, bonding resin and composite resin were applied over the treated dentin surfaces sequentially. All specimens were stored in $37^{\circ}C$ distilled water for 24 hours, then the tensile bond strength was measured and the treated dentin surfaces and fracured dentin surfaces were examined under a scanning electron microscope. The results were as follows: Bond strengths of acid-treated groups were higher than those of the untreated group. In the acid-treated groups, bond strength was found to be the highest in the 10-3 solution group followed by the 10% phosphoric acid group and the 10% polyacrylic acid group(P<0.01). On SEM examination of dentin surfaces, the untreated dentin surface showed a remaining smear layer and closed dentinal tubules. Dentin surfaces treated with 10 % polyacrylic acid showed a clean dentin surface without the smear layer, but showed remaining smear plugs in dentinal tubules. A dentin surface treated with 10% phosphoric acid or 10-3 solution showed open dentinal tubules without the smear layer or smear plugs. On SEM observation of the fractured dentin-resin interface, the untreated group showed that failure occurred in the smear layer. The group treated with 10% polyacrylic acid showed no resin tag remained in the dentinal tubules, but resin tags in the dentinal tubules were observed in the group treated with the 10% phosphoric acid or the 10-3 solution. On the failure mode examination, the higher the bond strength of the group, the higher the frequency of cohesive failure. The coefficient between bond strength and cohesive failure rate was 0.71.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.10 no.4
• /
• pp.450-456
• /
• 2022

In this study, as the preliminary research on the development of heating concrete members, compressive strength and accelerated chloride diffusion behavior in the mortar specimens containing C₁₂A₇ based binder and anhydrite was evaluated. Also, the effect of the mixing ratio of the citric acid based retarder was quantitatively evaluated by considering 4 levels of mixing cases. The compressive strength tests of the mortar specimen were performed referred to KS L ISO 679, and the accelerated chloride diffusion tests were performed according to NT BUILD 492 and ASTM C 1202. In the mortar with 0.3 % of retarder, the highest compressive strength was evaluated, which showed the strength development ratio of 127.6 % compared to the control case. It was considered that engineering performance was improved by effectively securing setting and curing time with 0.3 % of citric acid based retarder. As the result of the evaluation of the passed charge and the accelerated chloride diffusion coefficient, the evaluation results had similar behavior with the results of compressive strength. According to the previous study, the strength behavior and the chloride diffusion behavior had a linear relationship. The mixture showing the highest strength performance had the highest durability performance for chloride ingress, and the heating concrete development from this study will be performed in the future.

• Textile Coloration and Finishing
• /
• v.1 no.1
• /
• pp.54-62
• /
• 1989

The woven fabric composed of nylon 6 filaments was treated with aqueous solutions (20, 30, 40, 50, 60%) of formic acid at 3$0^{\circ}C$ for 10 minutes under unrestrained condition, and the shrinkage behavior and some kinds of properties were examined. The shrinkages of the constituent yarns and fabric were increased with formic acid concentration, but they were lower than that of the original filaments because of fabric-structural factors. And the shrinkage of the warp was lower than that of the weft because of the residual stress from weaving process. By the restraint forces such as fabric-structural factors and residual stress, the constituent filaments were damaged partially at 60% of formic acid concentration and the degree of damage on the warp was greater than on the weft. And though the fabric count were increased overall, the spacing between the warps was decreased prior to the weft and eliminated nearly at 60% of formic acid concentration. The thickness, tensile strength, elongation, and handle value of fabric were increased overall with formic acid concentration excepting that the tensile strength for both the warp and weft directions and the elongation for the warp direction were decreased instead by the damage of yarns. But the crease recovery was decreased except the case of the weft direction at 60% of formic acid concentration.

• Journal of the Korean Ceramic Society
• /
• v.18 no.4
• /
• pp.229-236
• /
• 1981

This study deals with the high temperature (600-135$0^{\circ}C$) properties of Kaolin-Phosphate-Water systems. Phosphoric acid, mono aluminum phosphate, mono ammonium phosphate, the mixture of phosphoric acid and mono aluminum phosphate, and the mixture of phosphoric acid and mono ammonium phosphate were used to characterize the M.O.R of the systems with to quantity of phosphates and firing temperature. Firing shrinkage, creeptest, DTA, TGA, and X-ray diffraction patterns were also measured in order to investigate the factors of strengthening. The resules of the experiments are as follows: 1. Linear shrinkage of kaolin-phosphate systems become larger as the firing temperature rise, and generally in the firing temperature of $600^{\circ}C$ and 100$0^{\circ}C$ the test pieces with phosphate binder show larger then Kaolin-Water system in linear shrinkage and reversed trends were found at 120$0^{\circ}C$ and 135$0^{\circ}C$. 2. Cold M.O.R. of kaolin-phosphate systems show higher trends in strength as the firing temperature rise. Comparing M.O.R. of test pieces after firing at 135$0^{\circ}C$, the mixture of phosphoric acid-mono aluminum phosphate, and phosphoric acid mono ammonium phosphate systems show higher strength than kaolin-mono aluminum phosphate system which widely used, and it shows highest strength when the mole ratio of phosphoric acid and mono ammonium phosphate is 1:1 among the test pieces of kaolin-phosphate systems. 3. The refractoriness of kaolin-phosphate systems are more deteriorated than Kaolin-Water system, and generally, the more addition of phosphate, the lower the refractoriness, however in the range of 4-8% phosphate addition, the difference of the fusion temperature is about 7$0^{\circ}C$. 4. The test pieces of T1 and T2 in creep test were same or even higher than kaolin-water system when 6% of phosphoric acid-mono ammonium phosphate was added to kaolin. 5. In case where the phosphoric acid-mono ammonium phosphate was added to kaolin in mole ratio 1:1 the cold M.O.R., after firing at 135$0^{\circ}C$, refractoriness and $T_2$ in creep test show better results than kaolin-mono-aluminum phosphate system which is widely used. 6. Phosphoric acid and mono ammonium phosphate react with kaolin in temperature over 100$0^{\circ}C$, and it forms aluminum phosphate.