• Title, Summary, Keyword: methyl acetate (MA)

Search Result 10, Processing Time 0.211 seconds

Tensile bond strength between auto-polymerized acrylic resin and acrylic denture teeth treated with MF-MA solution

  • Thongrakard, Ticha;Wiwatwarrapan, Chairat
    • The Journal of Advanced Prosthodontics
    • /
    • v.8 no.4
    • /
    • pp.285-289
    • /
    • 2016
  • PURPOSE. This study evaluated the effect of chemical surface treatment using methyl formate-methyl acetate (MF-MA) solution on the tensile bond strength between acrylic denture teeth and auto-polymerized acrylic resin. MATERIALS AND METHODS. Seventy maxillary central incisor acrylic denture teeth for each of three different brands (Yamahachi New Ace; Major Dent; Cosmo HXL) were embedded with incisal edge downwards in auto-polymerized resin in polyethylene pipes and ground with silicone carbide paper on their ridge lap surfaces. The teeth of each brand were divided into seven groups (n=10): no surface treatment (control group), MF-MA solution at a ratio of 25:75 (v/v) for 15 seconds, 30 seconds, 60 seconds, 120 seconds, 180 seconds, and MMA for 180 seconds. Auto-polymerized acrylic resin (Unifast Trad) was applied to the ground surface and polymerized in a pressure cooker. A tensile strength test was performed with a universal testing machine. Statistical analysis of the results was performed using two-way analysis of variance (ANOVA) and post-hoc Dunnett T3 test (${\alpha}$=.05). RESULTS. The surface treatment groups had significantly higher mean tensile bond strengths compared with the control group (P<.05) when compared within the same brand. Among the surface treatment groups of each brand, there were no significantly different tensile bond strengths between the MF-MA groups and the MMA 180 second group (P>.05), except for the Yamahachi New Ace MF-MA 180-second group (P<.05). CONCLUSION. 15-second MF-MA solution can be an alternative chemical surface treatment for repairing a denture base and rebonding acrylic denture teeth with auto-polymerized acrylic resin, for both conventional and cross-linked teeth.

Characteristics of Isothermal Analysis and Emulsion Copolymerization of Vinyl Acetate/Alkyl Acrylate (비닐아세테이트/알킬아크릴레이트계 에멀젼 공중합과 등온 열분해 특성)

  • Cho, Dae-Hoon;Choe, Sung-Il;Seul, Soo-Duk
    • Journal of Adhesion and Interface
    • /
    • v.13 no.2
    • /
    • pp.64-72
    • /
    • 2012
  • Vinyl acetate/alkyl acrylate copolymers were prepared by water-born emulsion copolymerization according to the compositional change of vinyl acetate and various alkyl acrylates such as methyl acrylate (MA), ethyl acrylate (EA), and n-butyl acrylate (BA). Ammonium persulfate (APS) was used as an initiator and poly(vinyl alcohol) (PVA) was used as a protective colloid. The significant result was described as follows. The activation energy determined by an isothermal analysis in the temperature region between $100{\sim}200^{\circ}C$ of the copolymer had the order of PVAc/PMA > PVAc/PEA > PVAc/PBA. The peel strengths before and after the plasma treatment were the order of PVAc/PMA > PVAc/PEA > PVAc/PBA.

Optimization of biodiesel production via methyl acetate reaction from cerbera odollam

  • Dhillon, Sandip Singh;Tan, Kok Tat
    • Advances in Energy Research
    • /
    • v.4 no.4
    • /
    • pp.325-337
    • /
    • 2016
  • Cerbera Odollam (sea mango) is a proven promising feedstock for the production of biodiesel due to its high oil content. Fatty acid methyl esters (FAME) were produced as the final reaction product in the transesterification reflux condensation reaction of sea mango oil and methyl acetate (MA). Potassium methoxide was used as catalyst to study its reacting potential as a homogeneous base catalyst. The initial part of this project studied the optimum conditions to extract crude sea mango oil. It was found that the content of sea mango sea mango oil was 55%. This optimum amount was obtained by using 18 g of grinded sea mango seeds in 250 ml hexane. The extraction was carried out for 24 hours using solvent extraction method. Response surface methodology (RSM) was employed to determine the optimum conditions of the reaction. The three manipulated variables in this reaction were the reaction time, oil to solvent molar ratio, and catalyst wt%. The optimum condition for this reaction determined was 5 hours reaction time, 0.28 wt% of catalyst and 1:35 mol/mol of oil: solvent molar ratio. A series of test were conducted on the final FAME product of this study, namely the FTIR test, GC-FID, calorimeter bomb and viscometer test.

Synthesis of 5-(p-Toluoyl)-1-Methylpyrrole-2-Acetic Acid [Tolmetin] (5-(p-톨루오일)-1-메틸피롤-2-아세트산의 합성)

  • Choi, Hong-Dae;Ma, Jung-Joo
    • YAKHAK HOEJI
    • /
    • v.36 no.4
    • /
    • pp.341-344
    • /
    • 1992
  • A facile method for tolmetin, which is a potent antiinflammatory agent, is described. Friedel-Crafts reaction of 1-methylpyrrole with ethyl ${\alpha}-chloro-{\alpha}-(methylthio)acetate$ (1) gave ethyl ${\alpha}-methylthio$-1-methyl-2-pyrroleacetate (4), which was readily converted into ethyl 1-methyl-2-pyrroleacetate (5) by reductive desulfurization with zinc dust in acetic acid. Tolmetin was synthesized by Friedel-Crafts acylation of (5) with p-toluoyl chloride, followed by hydrolysis of the resultant ethyl 5-(p-toluoyl)-1-methylpyrrole-2-acetate (6).

  • PDF

Properties of Capacity on Carbon Electrode in EC:MA Electrolytes - I. Effect of Mixing Ratio on the Electrochemical Properties - (EC:MA 혼합전해질에서 카본 전극의 용량 특성 - I. 전기화학적 특성에 대한 혼합비의 영향 -)

  • Park, Dong-Won;Kim, Woo-Seong;Son, Dong-Un;Kim, Sung-Phil;Choi, Yong-Kook
    • Applied Chemistry for Engineering
    • /
    • v.17 no.2
    • /
    • pp.183-187
    • /
    • 2006
  • The choice of solvents for electrolytes solutions is very important to improve the characteristics of charge/discharge in the Li-ion battery system. Such solvent systems have been widely investigated as electrolytes for Li-ion batteries. In this paper, the electrochemical properties of the solid electrolyte interphase film formed on carbon anode surface and the solvent decomposition voltage in 1 M LiPF6/EC:MA(x:y) electrolyte solutions prepared from the various mixing volume ratios are investigated by chronopotentiometry, cyclic voltammetry, and impedance spectroscopy. As a result, the solvent decomposition voltages are varied with the ionic conductivity of the electrolyte. Electrochemical properties of the passivation film were different, which are dependent on the mixture ratio of the solvents. Therefore, the most appropriate mixing ratio of EC and MA as a solvent in 1 M $LiPF_6/(EC+MA)$ system for Li-ion battery is approximately 1:3 (EC:MA, volume ratio).

Synthesis of Hexaprofen [2-(4-Cyclohexylphenyl) propionic Acid]

  • Choi, Hong-Dae;Ma, Jung-Joo;Son, Byeng-Wha
    • Archives of Pharmacal Research
    • /
    • v.15 no.2
    • /
    • pp.142-145
    • /
    • 1992
  • A novel preparative method for hexaprofen, which is a potent antiinflammatory agent, is described. Friedel-Crafts reaction of cyclohexylbenzene with ethyl $\alpha$-chloro-$\alpha$-(methylthio) acetate 1 and $\alpha$-chloro-$\alpha$-(methylthio) acetonitrile 2 afforded ethyl 2-(methylthio)-2-(4-cyclohexylphenyl) acetate 7 and 2-methylthio-2-(4-cyclohexylphenyl) acetonitrile 8, respectively. Compounds 7 and 8 were converted into the corresponding ethyl 2-methylthio-2-(4-cyclohexylphenyl) propionate 9 and 2-methylthio-2-(4-cyclohexylphenyl) propionitrile 10 by methylation with sodium hydride and methyl iodide. Hexaprofen 13 was prepard by hydrolysis of ethyl 2-(4-cyclohexylphenyl) propionate 11 and of 2-(4-cyclohexylphenyl) propionitrile 12 followed by desulfurization of compounds 9 and 10.

  • PDF

Antimutagenic Effects and Compounds Identified from Hexane Fraction of Persimmon Leaves (감잎 핵산획분의 항돌연변이 효과와 항돌연변이 물질의 GC-MS를 이용한 동정)

  • Moon, Suk-Hee;Kim, Jeong-Ok;Rhee, Sook-Hee;Park, Kun-Young;Kim, Kwang-Hyuk;Rhew, Tae-Hyong
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.22 no.3
    • /
    • pp.307-312
    • /
    • 1993
  • Methanol extract of dried persimmon leaves was fractionated to hexane, chloroform, ethyl acetate, butanol, and aqueous tractions. Hexane, butanol, and aqueous fractions had high yields of extracts. Hexane fraction among these fractions showed the highest inhibition rate on the mutagenicities of aflatoxin (AFB$_1$), dimethyl-amino-bi-phenyl (DMAB), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and 4-nitroquinoline-1-oxide (4-NQO) in Salmonella typhimurium TA100. Hexane fraction was further fractionated into eight fractions by silica gel column c-hromatography and thin layer chromatography (TLC). The fraction 5 on TLC exhibited the highest antimutagenic activity on AFB$_1$, DMAB, and MNNC. 1'-oxocannabinol, 3B-acetoxy-17-methyl-5a-18 (13-17) abeoardrost-13-one, 4-methoxy-2'6'-dinitro-3, 5-di-t-butylbiphenyl, 8, 9-dihydro-5, 6-dimethoxy-dibenz [c, h]isoquino [2, 1, 8-1 ma]carbazole-11, 16-dione were tentatively identified from this antimutagenic fraction by GC-MS.

  • PDF

Suppression of Co-intercalation on the Carbon Anode by MA Addition in a PC-base Electrolyte

  • Kim, Woo-Seong;Park, Dong-Won;Jung, Hwan-Jung;Choi, Yong-Kook
    • Bulletin of the Korean Chemical Society
    • /
    • v.27 no.1
    • /
    • pp.82-86
    • /
    • 2006
  • Propylene Carbonate (PC) has the interesting properties of being able to dissolve and dissociate lithium salts, thus leading to highly conducting electrolytes even at low temperatures. Moreover, electrolytes that contain PC are stable against oxidation at voltages up to ~5 V. However, it is known that, when lithium is intercalated into graphite in pure PC based electrolytes, solvent co-intercalation occurs, leading to the destruction of the graphite structure. (i.e., exfoliation). The objective of this study was to suppress PC decomposition and prevent exfoliation of the graphite anode by co-intercalation. Electrochemical characteristics were studied using Kawasaki mesophase fine carbon (KMFC) in different 1 M $LiPF_6$/PC-based electrolytes. Electrochemical experiments were completed using chronopotentiometry, cyclic voltammetry, impedance spectroscopy, X-ray diffraction, and scanning electron microscopy. From the observed results, we conclude that the MA and $Li_2CO_3$ additive suppressed co-intercalation of the PC electrolyte into the graphite anode. The use of additives, for reducing the extent of solvent decomposition before exfoliation of the graphite anode, could therefore enhance the stability of a KMFC electrode.

Synthesis and Swelling Kinetics of a Cross-Linked pH-Sensitive Ternary Copolymer Gel System (pH-민감성 삼성분계 공중합체 젤의 합성 및 팽윤 속도론)

  • Zafar, Zafar Iqbal;Malana, M.A.;Pervez, H.;Shad, M.A.;Momma, K.
    • Polymer(Korea)
    • /
    • v.32 no.3
    • /
    • pp.219-229
    • /
    • 2008
  • A pH sensitive ternary copolymer gel was synthesized in the presence of ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent through radical polymerization of vinyl acetate (VA), acrylic acid (AA) and methyl acrylate(MA) with a weight ratio of 1 : 1.3 : 1. A number of experiments were carried out to determine the swelling behavior of the gel under a variety of pH conditions of the swelling medium. As the pH of the swelling medium was changed from 1.0 to 8.0 at $37^{\circ}C$, the gel showed a shift in the pH-dependent swelling behavior from Fickian (n=0.3447) to non-Fickian (n=0.9125). The resulting swelling parameters were analyzed using graphical and statistical methods. The results showed that the swelling of the gel was controlled by the pH of the medium, i.e. $n=n_o{\exp}(S_{C}pH)$, where n is the diffusion exponent, $n_o(=28.9645{\times}10^{-2})$ is the pre-exponential factor and $S_C$(=0.1417) is pH sensitivity coefficient. The swelling behavior of the gel was also examined in aliphatic alcohols. The results showed that the rate of swelling increased with increasing number of carbon atoms in the alcoholic molecular chain.

Antioxidant Activities of Citrus unshiu Extracts obtained from Different Solvents (추출용매에 따른 진피 추출물의 항산화 활성)

  • Lee, Sung-Gu;Oh, Sung-Cheon;Jang, Jae-Seon
    • The Korean Journal of Food And Nutrition
    • /
    • v.28 no.3
    • /
    • pp.458-464
    • /
    • 2015
  • In this study, the total polyphenol content, electron donating ability (EDA) and inhibitory activity of glutathione S-transferase (GST) of freeze-dried Citrus unshiu extracts were examined. The Citrus unshiu extracts was obtained from four solvents such as ethyl acetate, acetone, methyl chloride and methanol, to evaluate its functional properties. Total polyphenol contents were measured in the two different extracts, and the extracts were screened for their potential antioxidant activities using tests such as electron donating ability (EDA), glutathione S-transferase (GST). The total polyphenol contents of Citrus unshiu extracts were $928.48{\pm}1.19{\mu}g\;GAE/mL$ in ethyl acetate (EA), $886.03{\pm}0.44{\mu}g\;RE/mL$ in acetone (AC), $413.08{\pm}1.39{\mu}g\;GAE/mL$ in methylene chloride (MC), $12,648.60{\pm}0.56{\mu}g\;GAE/mL$ in methanol (MeOH), respectively. Also, the total polyphenol contents of EtOH Citrus unshiu extracts were $664.64{\pm}0.74{\mu}g\;GAE/mL$ in EA, $702.67{\pm}0.85{\mu}g\;RE/mL$ in AC, $429.64{\pm}0.61{\mu}g\;GAE/mL$ in MC, $16,108{\pm}0.73{\mu}g\;GAE/mL$ in MeOH, respectively. The total polyphenol contents were significantly difference (p<0.05) between the solvents. The electron donating ability of Citrus unshiu extracts were $62.80{\pm}0.36%$ in EA, $97.43{\pm}0.51%$ in AC, $52.20{\pm}0.30%$ in MC, $97.63{\pm}0.46%$ in MeOH, respectively. Also, the electron donating ability of EtOH Citrus unshiu extracts were $51.49{\pm}0.26%$ in EA, $63.17{\pm}0.31%$ in AC, $67.68{\pm}0.55%$ in MC, $96.18{\pm}0.41%$ in MA, respectively. The electron donating ability were significantly difference (p<0.05) between the solvents. The inhibitory activity of glutathione S-transferase in Citrus unshiu extracts were $76.22{\pm}0.65%$ in EA, $31.73{\pm}0.48%$ in MC, $97.48{\pm}0.56%$ in MeOH, respectively. Also, inhibitory activity of glutathione S-transferase in EtOH Citrus unshiu extracts were $75.54{\pm}0.55%$ in EA, $73.53{\pm}0.38%$ in MC, $48.70{\pm}0.46%$ in MeOH, respectively. The inhibitory activity of glutathione S-transferase were significantly difference (p<0.05) between the solvents. These results indicated that the Citrus unshiu extracts is a high-valued food ingredient and the extraction with methanol will be useful as a nutritional source with natural antioxidant activities. Considering high consumer demand beneficial health effects, Citrus unshiu extracts can be utilized to develop functional food health- promoting and natural antioxidant agents.