• Title, Summary, Keyword: magnesium hydroxide

Search Result 107, Processing Time 0.065 seconds

Evaluation of Neutralizing Capacities of Antacid Products (제산제의 중화 능력의 평가 연구)

  • 박경호;차수만;최진석;김낙두
    • YAKHAK HOEJI
    • /
    • v.27 no.2
    • /
    • pp.139-148
    • /
    • 1983
  • The neutralizing capacities of the antacids, which are frequently used in Korean market, were evaluated in vitro by the methods of Resset and Rice, Fordtran and Collyns, and modified Beekman, respectively. The antacids used in the study are two kinds, the one is preparations from Seoul National University Hospital and the other is products from pharmaceutical companies, and their components are aluminum phosphate, aluminum hydroxide, magnesium aluminum hydroxide, magnesium hydroxide, basic aluminum sucrose sulfate and $2MgO{\times}Al_{2}O_{3}{\times}SiO_{3}$, etc. The hospital preparations, DMC and MAC powders, showed most powerful and sustained neutralizing capacities, i.e. they maintained the pH range from 5 to 8 for 60min, Whereas pharmaceutical products, aluminum hydroxide gel containing magnesium hydroxide and magnesium aluminum hydroxide gel exhibited a moderate capacities, i.e pH ranged from 3 to 6, and aluminum phosphate, $2MgO{\times}Al_{2}O_{3}{\times}SiO_{2}$ and basic aluminum sucrose sulfate displayed a weak activity, pH ranged from 2 to 3. When the therapeutic doses of aluminum hydroxide gel containing magnesium hydroxide and magnesium aluminum hydroxide gel were divided into 2 doses and each dose was used at the interval of 30min., the divided doses kept more prolonged higher pH than the single therapeutic dose. Milliequivalents of neutralizing capacities of each antacid were measured by the method of Fordtran and Collyns. The milliequivalents per 1ml of aluminum hydroxide gel, aluminum hydroxide gel containing magnesium hydroxide, magnesium aluminum hydroxide gel and aluminum phosphate were 2.87, 2.86, 2.57, and 0.67, respectively. The milliequivalents per 100mg of preparations, i.e. MAC powder, dried aluminum hydroxidgel, DMC powder, 2MgO, $Al_{2}O_{3}$. $SiO_{2}$, magnesium aluminum hydroxide and basic aluminum sucrose sulfate were 1.91, 1.68 1.63, 1.45, 1.44, and 0.44, respectively.

  • PDF

Effect of Mg-Sulfate and Mg-Hydroxide on Growth of Chinese Cabbage (배추에 대한 황산고토와 수산화고토의 비효 비교)

  • Lee, Sang-Jo;Lee, Sung-Ho;Shin, Hyun-Jin;Cho, Hyun-Jong;Kim, Bok-Jin;Chung, Jong-Bae
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.36 no.4
    • /
    • pp.218-224
    • /
    • 2003
  • Magnesium hydroxide, which recently registered as a Mg fertilizer, is greatly different from magnesium sulfate in its solubility and effect on soil pH. In this study, the effects of magnesium hydroxide and magnesium sulfate on growth of chinese cabbage were compared at the application rate of $300kg\;MgO\;ha^{-1}$ in a Gyeongsan clay loam soil. Although magnesium hydroxide was effective in increasing number of leaf and fresh weight, overall effects of magnesium hydroxide and magnesium sulfate on the growth of chinese cabbage were not significantly different ($p{\leq}0.05$). Comparing the two magnesium fertilizer treatments, magnesium content of chinese cabbage was relatively higher in the magnesium sulfate treatment in the early stage of growth, but it was higher in the magnesium hydroxide treatment at harvest. Contents of Ca, P, and K in chinese cabbage were relatively higher in the magnesium hydroxide treatment than those in magnesium sulfate treatment. But, the differences in nutrient uptakes by chinese cabbage between the treatments were not significant ($p{\leq}0.05$). Therefore, magnesium hydroxide is expected to be used with nearly the same effects on crops as magnesium sulfate at the same application rate of Mg. Soil pH in the treatment of magnesium sulfate was lower than that of control treatment, but magnesium hydroxide could increase pH. Magnesium hydroxide can be used preferentially in acid and/or sandy soils, where magnesium sulfate can induce further soil acidification and leaching loss of Mg is often a severe problem.

Preparation of Mg(OH)2-Melamine Core-Shell Particle and Its Flame Retardant Property (멜라민이 코팅된 수산화마그네슘 입자의 제조와 그 복합입자의 난연특성)

  • Lim, Hyung-Mi;Yoon, Joon-Ho;Jeong, Sang-Ok;Lee, Dong-Jin;Lee, Seung-Ho
    • Korean Journal of Materials Research
    • /
    • v.20 no.12
    • /
    • pp.691-698
    • /
    • 2010
  • Magnesium hydroxide-melamine core-shell particles were prepared through the coating of melamine monomer on the surface of magnesium hydroxide in the presence of phosphoric acid. The melamine monomer was dissolved in hot water but recrystallized on the surface of magnesium hydroxide by quenching to room temperature in the presence of phosphoric acid. The core-shell particle was applied to low-density polyethylene/ ethylene vinyl acetate (LDPE/EVA) resin by melt-compounding at $180^{\circ}C$ as flame retardant. The effect of magnesium hydroxide and melamine content has been studied on the flame retardancy of the core-shell particles in LDPE/EVA resin according to the preparation process and purity of magnesium hydroxide. Magnesium hydroxide prepared with sodium hydroxide rather than with ammonia solution revealed higher flame retardancy in core-shell particles with LDPE/EVA resin. At 50 wt% loading of flame retardant, core-shell particles revealed higher flame retardancy compared to that of the exclusive magnesium hydroxide in LDPE/EVA composite, and it was possible to satisfy the V0 grade in the UL-94 vertical test. The synergistic flame retardant effect of magnesium hydroxide and melamine core-shell particles was explained as being due to the endothermic decomposition of magnesium hydroxide and melamine, which was followed by the evolution of water from the magnesium hydroxide and porous char formation due to reactive nitrogen compounds, and carbon dioxide generated from melamine.

Combustive Properties of Low Density Polyethylene and Ethylene Vinyl Acetate Composites Including Magnesium Hydroxide (저밀도 폴리에틸렌과 에틸렌 비닐 아세테이트에 수산화마그네슘을 첨가한 복합체의 연소성)

  • Chung, Yeong-Jin
    • Fire Science and Engineering
    • /
    • v.25 no.5
    • /
    • pp.69-75
    • /
    • 2011
  • It was performed to test the combustive properties of low density polyethylene and ethylene vinyl acetate (LDPE-EVA) composite by the addition of magnesium hydroxide. Flame retardant of natural magnesium hydroxide was added to the mixture of LDPE-EVA in 40 to 80 wt% concentration. The composite was compounded to prepare specimen for combustive analysis by cone calorimeter (ISO 5660-1). Comparing with virgin LDPE-EVA, the specimens including the magnesium hydroxide had lower flashover possibility. It is supposed that the combustive properties in the composites decreased due to the endothermic decomposition of magnesium hydroxide. The specimens with magnesium hydroxide showed both the lower total heat release rate (THR) and lower CO production rate than those of virgin polymer. As the magnesium hydroxide content increases, the total smoke release (THR) and smoke extinction area (SEA) decreased.

Preparation and Characterization of Emulsified Chlorosulfonated Polyethylene Rubber (CSM) (유화 Chlorosulfonated Polyethylene Rubber (CSM)의 제조 및 특성 연구)

  • Choi, Seo-Young;Lee, Eun-Kyoung;Choi, Kyo-Chang
    • Elastomers and Composites
    • /
    • v.40 no.1
    • /
    • pp.12-21
    • /
    • 2005
  • In this work, magnesium carbonate and calcium hydroxide as metallic crosslinking agent were added to chlorosulfonated polyethylene rubber (CSM) emulsion to enhance the mechanical properties of emulsion film such as tensile strength, elongation at break, and tear strength and crosslinking density, thermal features, and surface energy were also investigated. Crosslinking density of the CSM emulsion film with increasing the amount of magnesium carbonate and calcium hydroxide increased, leading to the enhancement of water resistance. It was shown that compared with calcium hydroxide, magnesium carbonate had a little higher crosslinking density and $T_g$ value. The surface energy and mechanical characteristics of the CSM emulsion film, however, showed somewhat different behaviors. The highest surface energy, tensile strength, and tear strength were observed when 0.75% for magnesium carbonate and 1.0% for calcium hydroxide were added respectively. Therefore, it can be concluded that as metallic crosslinking agent to improve water resistance and mechanical properties of the CSM emulsion, magnesium carbonate is more preferable to calcium hydroxide.

Synthesis and Characteristics of Magnesium Hydroxide Group Flame Retardant for Polymer Addtives (고분자 첨가제인 난연제로서의 수산화마그네슘계 물질의 합성과 특성)

  • Lee, Dong-Kyu;Kang, Kuk-Hyoun;Lee, Jin-Hwa
    • Journal of the Korean Applied Science and Technology
    • /
    • v.26 no.4
    • /
    • pp.385-393
    • /
    • 2009
  • Different types magnesium hydroxide groups have been obtained using the hydrothermal precipitation technique from magnesium sulfate and calcium carbonate solution. The Mg atom coordinated around O atom of ${SO_4}^{2-}$ in another layer to form a multi-layer structure crystal. The influence of synthesis parameters on the morphological characteristics and size of magnesium hydroxide groups precipitated in aqueous were investigated such as different of additive and pH. Magnesium hydroxide groups were decomposed gradually and converted finally to MgO particles after heated in air temperature up to $1050^{\circ}C$. The particle size and it's distribution morphology, crystal phase and thermal behavior of the samples were characterized through XRD, SEM, EDS, and TG/DTA.

Combustion-Retardation Properties of Low Density Polyethylene and Ethylene Vinyl Acetate Mixtures with Magnesium Hydroxide (수산화마그네슘이 첨가된 저밀도 폴리에틸렌과 에틸렌 비닐 아세테이트 혼합물의 난연성)

  • Chung, Yeong-Jin;Lim, Hyung Mi;Jin, Eui;Oh, JungKyoo
    • Applied Chemistry for Engineering
    • /
    • v.22 no.4
    • /
    • pp.439-443
    • /
    • 2011
  • It was performed to test the combustive properties of low density polyethylene and ethylene vinyl acetate (LDPE-EVA) mixture by the addition of magnesium hydroxide. Flame retardant of natural magnesium hydroxide was added to the mixture of LDPE-EVA in 40 to 80 wt% concentration. The composite was compounded to prepare specimen for combustive analysis by cone calorimeter (ISO 5660-1). Comparing with virgin LDPE-EVA, the specimens including the magnesium hydroxide had lower combustive properties. It is supposed that the combustion-retardation properties in the composites improved due to the endothermic decomposition of magnesium hydroxide. The specimens with magnesium hydroxide showed both the lower peak heat release rate (PHRR) and lower effective heat of combustion (EHC) than those of virgin polymer. As the magnesium hydroxide content increases, time to ignition increased and the peak heat release rate decreased.

Studies on Magnesia Production. Production of Magnesium Hydroxide from Bittern and Sea Water (마그네시아 製造에 關한 硏究 간수, 海水로 부터 水酸化마그네슘 製造)

  • Maeng, Jung-Jae;Chang, In-Soon
    • Journal of the Korean Chemical Society
    • /
    • v.9 no.1
    • /
    • pp.49-54
    • /
    • 1965
  • One of the difficult and time consuming problems in the production of magnesia from sea water is a settling rate of magnesium hydroxide. In this experiments, authors attempted to accelerate its settling rate by addition of various sedimenting agents as C.M.C., Separan and Starch, and sought for optimum calcination temperature for domestic dolomite, as alkali source, mole ratio of dolomite milk to bittern. It is observed through experiments that the small amounts of sedimenting agents, C.M.C., Separan, starch, 20 mg/l, 40 mg/l, 400mg/l, respectively increase the settling rate of magnesium hydroxide by 8 times or more. The following conditions resulted in good yield of magnesium hydroxide from sea water with relatively tolerable calcium oxide contaminated for the magnesium clinker. Calcinating temperature, $1,100{\sim}1,200^{\circ}C$, mole ratio of 10% dolomite milk to magnesium salts in sea water or bittern, 1. 2 : 1.

  • PDF

Shape Changes of Mg(OH)2 with Different Magnesium Precursors in Low Temperature (전구체에 따른 Mg(OH)2의 저온합성에서 형상변화)

  • Kang, Kuk-Hyoun;Jeong, Sun-In;Lee, Dong-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.14 no.4
    • /
    • pp.2049-2054
    • /
    • 2013
  • Recently, magnesium hydroxide ($Mg(OH)_2$) has many applications in various field, due to its outstanding characteristics such as a nontoxic, noncorrosive and thermal stable properties. In this study, different shapes of flower and flake type magnesium hydroxide were synthesized by precipitation method at room temperature using $MgSO_4$, $MgCl_2$ and $Mg(NO_3)_2$ as magnesium sources, NaOH and $NH_3$ as alkaline sources. Influence of synthesis on the morphological characteristics, sizes and shapes of magnesium hydroxide particles, was investigated, such as different precursors and parameters. The shape of magnesium hydroxide depend on magnesium and alkali sources. Average size of flower particle had about $1{\mu}m$, and flake had about 20 ~ 50 nm. The synthesised magnesium hydroxide groups were characterized by XRD, FE-SEM, FT-IR, EDS, PSA and TG.

Synthesis and Surface Modification of Magnesium Hydroxide by Hydrothermal Method (수열법에 의한 수산화 마그네슘의 합성과 표면개질)

  • Lee, Hae-Young;Kang, Kuk-Hyoun;Lee, Dong-Kyu
    • Journal of the Korean Applied Science and Technology
    • /
    • v.29 no.1
    • /
    • pp.149-158
    • /
    • 2012
  • Magnesium hydroxide[$Mg(OH)_2$] was prepared by hydrothermal method using oleic acid as surface modifier. $Mg(OH)_2$ particles exhibit flake morphology with micrometer in size and the surface modification starts from the reaction of $C_{17}H_{33}COO^-$ group, derived from oleic acid molecule in alkaline environments. It is found that hydrothermal treatment conditions such as pH, temperature and reaction time are important for the control of the morphology and properties of surface modified magnesium hydroxide. The obtained magnesium hydroxide groups were characterized by FE-SEM, XRD, FT-IR, TGA. The dispersion in organic solution was determined by sedimentation test and compared with the result of raw $Mg(OH)_2$.