• Title/Summary/Keyword: amine groups

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Adsorption Mechanism of Solid Acid in Nonaqueous Solution (固體酸의 非水溶液에서의 吸着메카니즘에 관한 硏究)

  • Kwun, Oh-Cheun
    • Journal of the Korean Chemical Society
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    • v.9 no.4
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    • pp.185-189
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    • 1965
  • Korean acid clays and silica gel were put into action on benzene solution of dye, such as aniline yellow, o-nitro aniline and oil orange, and then the adsorptivity of dye in nonaqueous solution was measured, with the result that adsorptivity was greater with silica than acid clays and it had no relation to acidity. And when chemical compounds, such as amine, alcohol, halogen derivative, were added to each dye solution by 10%(in volume), the change of the adsorptivity of dye by solid acid(that is, the interfered adsorption rate) decreased in order of amine > alcohol > halogen derivative, and in homologue the smaller the molecular weight, the larger was the effect. So adsorption in nonaqueous solution was a selective adsorption of chemical compounds which contained negative groups such as amine and hydroxyl radicals, and it had no relation to surface tension and showed inverted phenomenon of Traube series. It is guessed that the inverted phenomenon (the interfered adsorption phenomenon) was due to the polar chemical adsorption between active $SiO_2$ which was an origin of solid acid and the adsorbed substances, considering that the order of inversion was nearly in accord with dipole moment of added solvents. The results of this study led to find adsorption mechanism and inverted phenomenon of Traube series in nonaqueous solution.

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High performance epoxy nanocomposites with amine-functionalized graphenes

  • Park, Sol-Mon;Kim, Dae-Su
    • Proceedings of the KAIS Fall Conference
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    • 2010.11a
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    • pp.470-473
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    • 2010
  • Graphene, consisting of a single layer of carbon in a two-dimensional lattice, has been emerging as a fascinating material with many unique physical, chemical and mechanical properties. In this study, graphenes were prepared by a chemical method. To develop high performance polymer nanocomposites reinforced by graphenes, adequate dispersion of the fillers and strong interfacial bonding between the fillers and the polymer matrix are essential. The purpose of this study was to examine the influence of introducing amine groups on the surfaces of graphenes. FT-IR spectroscopy, SEM were used to confirm the functionalization. Epoxy nanocomposites comprising the graphenes were prepared and their characteristics were investigated by DSC, DMA and TMA. Fracture surfaces of the nanocomposites were investigated by SEM. The functionalized graphenes induced strong interfacial bonding than the pristine graphenes and resulted in considerable improvements in the performance of the nanocomposites.

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Characteristics of Crosslinked Resin Modified with Nitriles (니트릴에 의해 개질된 가교구조 수지의 특성)

  • Sim, Mi-Ja
    • Korean Journal of Materials Research
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    • v.9 no.4
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    • pp.373-377
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    • 1999
  • The cure mechanicsm and cure kinetics of diglycidyl ether of bisphenol A(DGEBA)/4,4'-methylene dianiline(MDA)/nitrile(MN, SN, GN) systems were studied by FT-IR and DSC to develop new applications in the biomedical polymer fields. The network structure of the DGEBA/MDA system was changed to the chain-extended network structure by the addition of nitriles. The reactions contributed to the chain extension were the primary amine-nitrile and hydroxyl-nitrile reactions. The chain-extended network structure could be indirectly proved by the decrement of T\ulcorner and the increment of impact strength with the increasing nitrile content. The cure rate of DGEBA/MDA/nitrile system was lower than that of DGEBA/MDA system due to the disturbance of nitrile group in the reaction of primary amine and epoxide groups.

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Spectroscopic Analysis on the Michael Addition Reaction between Secondary Amino Group Containing Silica Nanoparticles with (Meth)acrylate Monomers (2차 아미노기를 갖는 실리카 나노입자와 (메타)아크릴레이트 단량체와의 마이클 부가반응에 대한 분광학적 분석)

  • Jeon, Ha-Na;Ha, Ki-Ryong
    • Polymer(Korea)
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    • v.36 no.5
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    • pp.668-676
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    • 2012
  • In this study, we modified silica nanoparticles with bis[3-(trimethoxysilyl)propyl]amine (BTMA) silane coupling agent to introduce secondary amino groups on the silica surface. After modification of silica, we investigated effects of different types of (meth)acrylate group containing monomers on the Michael addition reaction to introduce reactive (meth)acrylate groups on the BTMA modified silica surface. We used two kinds of (meth)acrylate monomers, trimethylolpropane ethoxylate triacrylate (TMPET) which has three identical acrylate groups, and 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) which has one acrylate and one methacrylate group. We used fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and solid state cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR) to understand reactions between NH groups on the silica surface with (meth)acrylate groups of TMPET and AHM monomers. We found almost complete Michael addition reaction between all three acrylate groups of TMPET with NH groups on the BTMA modified silica. But, for the AHM treatment of BTMA modified silica, we found Michael addition reaction occurred only between acrylate groups of AHM and NH groups of silica surface, not between methacrylate groups of AHM and NH groups of BTMA modified silica surface.

Resistive Switching Memory Devices Based on Layer-by-Layer Assembled-Superparamagnetic Nanocomposite Multilayers via Nucleophilic Substitution Reaction in Nonpolar Solvent

  • Kim, Yeong-Hun;Go, Yong-Min;Gu, Bon-Gi;Jo, Jin-Han
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.243.1-243.1
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    • 2011
  • We demonstrate a facile and robust layer-by-layer (LbL) assembly method for the fabrication of nonvolatile resistive switching memory (NRSM) devices based on superparamagnetic nanocomposite multilayers, which allows the highly enhanced magnetic and resistive switching memory properties as well as the dense and homogeneous adsorption of nanoparticles, via nucleophilic substitution reaction (NSR) in nonpolar solvent. Superparamagnetic iron oxide nanoparticles (MP) of about size 12 nm (or 7 nm) synthesized with oleic acid (OA) in nonpolar solvent could be converted into 2-bromo-2-methylpropionic acid (BMPA)-stabilized iron oxide nanoparticles (BMPA-MP) by stabilizer exchange without change of solvent polarity. In addition, bromo groups of BMPA-MP could be connected with highly branched amine groups of poly (amidoamine) dendrimer (PAMA) in ethanol by NSR of between bromo and amine groups. Based on these results, nanocomposite multilayers using LbL assembly could be fabricated in nonpolar solvent by NSR of between BMPA-MP and PAMA without any additional phase transfer of MP for conventional LbL assembly. These resulting superparamagnetic multilayers displayed highly improved magnetic and resistive switching memory properties in comparison with those of multilayers based on water-dispersible MP. Furthermore, NRSM devices, which were fabricated by LbL assembly method under atmospheric conditions, exhibited the outstanding performances such as long-term stability, fast switching speed and high ON/OFF ratio comparable to that of conventional inorganic NRSM devices produced by vacuum deposition.

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Synthesis of Poly(Styrene-co-GMA) and its Application as in situ Reactive Compatabilizer (Poly(Styrene-co-GMA)의 합성과 in situ Reactive Compatabilizer 로서의 응용)

  • Kim, Ju-Young;Suh, Kyung-Do
    • Applied Chemistry for Engineering
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    • v.3 no.3
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    • pp.499-506
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    • 1992
  • Copolymer of Styrene and GMA(glycidyl methachylate), having reactive ratios of $r_1=0.53$, $r_2=0.44$, was synthesized in dioxane using AIBN as free radical initiator. Followed by the reaction of ethylene diamine with copolymer PGS, amine groups were introduced to the PGS(NPGS). The composition of copolymer was determined by elemental analyzer. Poly(glycidyl methacrylate) (PGMA) was obtained in benzene using AIBN as free radical initiator. The NPGS-PGMA blend of 50/50 composition was prepared by mixing these polymers in THF at $65^{\circ}C$. Glass transition temperature (Tg) of NPGS-PGMA blend was measured by DSC. The blend showed a single Tg. Accordingly, it was clear that the NPGS was compatible with PGMA. An intermolecular reaction between amine groups of NPGS and epoxy groups of PGMA imparts compatibility in the NPGS-PGMA blend. When the NPGS-PGMA blend was added to the incompatible PS-PGMA blend, PS-PGMA blend showed Tg change. Scanning Electron Micrograph(SEM) showed a fine morphology in this blend. Consequently, it was apparent that the NPGS-PGMA blend acted as a compatibilizer for the PS-PGMA blend.

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Repairing Damaged Hair Using Pentapeptides of Various Amino Acid Sequences with Crosslinking Reaction

  • Choi, Wonkyung;Son, Seongkil;Song, Sang-Hun;Kang, Nae Gyu;Park, Sun-gyoo
    • Korea Journal of Cosmetic Science
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    • v.2 no.1
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    • pp.11-19
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    • 2020
  • The aim of this study is to investigate the effect of various pentapeptides on hair repair depending on the characteristics of comprising amino acids using crosslinking agents in hair. Total ten peptides were synthesized with two kinds of amino acids respectively, of which were previously categorized according to R group of the amino acids contributing to the characteristic of each peptide: STTSS (Ser-Thr-Thr-Ser-Ser), LIILL (Leu-Ile-Ile-Leu-Leu), CMMCC (Cys-Met-Met-Cys-Cys), DEEDD (Asp-Glu-Glu-Asp-Asp), RKKRR (Arg-Lys-Lys-Arg-Arg), TAMRA-STTSS, TAMRA-LIILL, TAMRA-CMMCC, TAMRA-DEEDD, and TAMRA-RKKRR. Pentapeptide alone, or pentapeptides with crosslinking agents such as polymeric carbodiimide (PCI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were treated to chemically damaged hair. Hair diameter and break strength (N = 40/case) were measured to calculate tensile strength of hair for computing hair repair ratio, and fluorescence yields (N = 20/case) were collected for hair treated with TAMRA-peptides. The tensile strength of hair treated with pentapeptides alone, or pentapeptides with cross-linking agents is consistent with the fluorescence yield from the microscope images of the cross-sectioned hair in vision and in numerical values. Pentapeptides consisting of hydrophobic amino acids (LIILL), amino acids with sulfur (CMMCC), and basic amino acids (RKKRR) increased the tensile strength in perm-damaged hair. Pentapeptides with no extra carboxyl/amine groups in R group of amino acids resulted in no significant differences in hair strength and fluorescence yield among hairs treated with alone and with crosslinkers. Pentapeptides with extra carboxyl groups or amine groups enabled further strengthening of hair due to increased bonds within the hair after carbodiimide coupling reaction. The hair repairs of pentapeptides with various amino acid sequences were studied using crosslinking. Depending on the physical characteristics of comprising amino acids, the restoration of damaged hair was observed with tensile strength of hair and fluorescence signals upon cross-sectioned hair in parallel to possibly understand the binding tendency of each pentapeptide within the hair.

Diagnostic Values of pH of Vaginal Discharge, Amine Test, and Microscopic Examination of Infectious Vaginitis (감염성 질염에 대한 질내 산도측정, Amine 검사 및 현미경 검사의 진단적 가치)

  • Choi, Jae-Dong;Kim, Gi-Duk;Koh, Min-Whan;Lee, Tae-Hyung;Chung, Wun-Yong
    • Journal of Yeungnam Medical Science
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    • v.5 no.2
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    • pp.129-139
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    • 1988
  • Vaginitis is one of the most common disease in gynecologic field in recent days. About 90% of these patients suffer from the infection of the vagina caused by Gardnerella vaginalis, Candida, or Trichomonas, either alone or in combination. For the effective diagnosis and management, it is essential to get an accurate identification of the causative agent. Applying simple and easy diagnostic methods such as pH of vaginal discharge, amine test and microscopic examination of wet mount preparation of normal saline and 10% KOH to 549 cases of randomly selected patients visiting Out-patient Department of Obstetrics and Gynecology of Yeung-nam University Hospital through May 1st to Sept. 31st, 1987, the following results were obtained. 1. In the Gardnerella vaginitis vaginal pH was more than 5.0 in 81.0% of total cases, positive amine test in 62.8%, decreased lactobacilli in 77.4% & decreased WBC counts in 70.1%, In the Trichomonas vaginitis vaginal pH more than 5.0 was noted in 93.3% of the cases, negative amine test in 90%, decreased lactobacilli in 90% & increased WBC counts in 93.3%, whereas Candida vaginitis and normal groups showed vaginal pH of 3.0~4.0 in 83.2%, negative amine test in 100%, normal distribution of lactobacilli in 89.7%, normal WBC counts in 72.4%. 2. The accuracy rates of physical diagnosis by wet mount preparation of normal saline and 10% KOH revealed 26.3%, 47.5% % 70,0% in Gardnerella vaginitis, Candida vaginitis, and Trichomonas vaginitis, respectively. The vaginal pH and amine test showed 83.2% of accuracy rate in Candida vaginitis group, 60.6% in Gardnerella vaginitis group and 83.3% III Trichomonas vaginitis group. 3. In 23 cases of Gardnerella vaginitis showing vaginal pH of 3.0 or 4.0 and positive amine test, the clue cells were observed in 10% or less in 12 cases, 30% in 5 cases, 50% in 4 cases and 50% or more in 2 cases. In summary vaginal pH and amine test could be useful in screening and differentiating the different types of infectious vaginitis. Furthermore by adding microscopic examination of normal saline and 10% KOH wet mount preparation to them, they not only could obtain higher diagnostic accuracy rate but would be more valuable in selecting the patients requiring cultures to confirm the diagnoses.

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Effect of CQ-amine ratio on the degree of conversion in resin monomers with binary and ternary photoinitiation systems

  • Moon, Ho-Jin;Shin, Dong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.37 no.2
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    • pp.96-103
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    • 2012
  • Objectives: This study evaluated the effect of camphorquinone (CQ)-amine ratio on the C=C double bond conversion of resins with binary and ternary photoinitiation systems. Materials and Methods: Two monomer mixtures (37.5 Bis-GMA/37.5 Bis- EMA/25 TEGDMA) with binary systems (CQ/DMAEMA in weight ratio, group A [0.5/1.0] and B [1.0/0.5]) and four mixtures with ternary system (CQ/OPPI/DMAEMA, group C [0.1/1.0/0.1], D [0.1/1.0/ 0.2], E [0.2/1.0/0.1] and F [0.2/1.0/0.2]) were tested: 1 : 2 or 2 : 1 CQ-amine ratio in binary system, while 1 : 1 ratio was added in ternary system. The monomer mixture was cured for 5, 20, 40, and 300 sec with a Demetron 400 curing unit (Demetron). After each exposure time, degree of conversion (DC) was estimated using Fourier transform infrared (FTIR) spectrophotometer (Nicolet 520, Nicolet Instrument Corp.). The results were analyzed by ANOVA followed by Scheffe test, with p = 0.05 as the level of significance. Results: DC (%) was expressed in the order of curing time (5, 20, 40, and 300 sec). Group A ($14.63{\pm}10.42$, $25.23{\pm}6.32$, $51.62{\pm}2.69$, $68.52{\pm}2.77$); Group B ($4.04{\pm}6.23$, $16.56{\pm}3.38$, $37.95{\pm}2.79$, $64.48{\pm}1.21$); Group C ($16.87{\pm}5.72$, $55.47{\pm}2.75$, $60.83{\pm}2.07$, $68.32{\pm}3.31$); Group D ($23.77{\pm}1.64$, $61.05{\pm}1.82$, $65.13{\pm}2.09$, $71.87{\pm}1.17$); Group E ($28.66{\pm}2.92$, $56.68{\pm}1.33$, $60.66{\pm}1.17$, $68.78{\pm}1.30$); Group F ($39.74{\pm}6.31$, $61.07{\pm}2.58$, $64.22{\pm}2.29$, $69.94{\pm}2.15$). Conclusion: All the monomers with ternary photoinitiation system showed higher DC than the ones with binary system, until 40 sec. Concerning about the effect of CQ-amine ratio on the DC, group A converted into polymer more than group B in binary system. However, there was no significant difference among groups with ternary system, except group C when cured for 5 sec only.

Studies on the Coating Structure and Printability of Coated Paper(II) - Effect of Ionic Groups of Latices on Coating Structure - (도공층 구조 및 도공지의 인쇄적성에 관한 연구(II) - 라텍스 이온기가 도공층 구조에 미치는 영향 -)

  • Lee, Yong-Kyu;Park, Kyu-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.25 no.4
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    • pp.10-16
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    • 1997
  • This study was carried out to improve coating structure by controlling the electrostatic interaction of coating components and by changing the coating structure of coated paper prepared with amphoteric and anionic latices. The results indicated that amphoteric latex copolymerized with carboxylic and amine groups had stronger interaction with other coating components than anionic latex with branched carboxylic group by controlling pH. These properties of amphoteric latex showed positive effects on viscosity rheology, and supernatant sediment of coating color. The coated paper using amphoteric latex had also produced more porous and smoother coverage of the coating layer than that using anionic latex. This porous and smooth coating layer showed better optical properties and printability than those of anionic latex such as opacity, porosity, ink set-off, and wet ink receptivity.

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