• Title/Summary/Keyword: coupling agents

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Reactions with Heterocyclic Amidines $(Vl)^1$: Synthesis of some new sym. and assym. pyrazolotriazines and pyrazolo[4,5-e]pyrimidine derivatives

  • Ali Elagamey, Abdel Ghani
    • Archives of Pharmacal Research
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    • v.10 no.3
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    • pp.173-178
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    • 1987
  • Several new pyrazolo [1, 5-a]-S-triazine, pyrazolo [4, 5, -elpyrimidine, pyrazolo [1, 5-a] pyrimidine derivatives were synthesized via condensation of 3-antipyrinyl-5-amino-pyrazole (2) with $\beta$$-bifunctional reagents. The azo analogues of pyrazolo [1, 5-a] pyrimidines ; i. e. pyrazolo [5, 1, c]-as-triazine and pyrazolo[5, 1, -c]-as-benzotriazine were synthesized by coupling of diazotized 2-with agents containing active hydrogen.

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Synthesis and Antiviral Activity of Novel Anomeric Branched Carbocyclic Nucleosides

  • Kim, Ai-Hong;Hong, Joon-Hee
    • Archives of Pharmacal Research
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    • v.28 no.10
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    • pp.1105-1110
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    • 2005
  • Novel anomeric branched carbocyclic nucleosides were synthesized from 1,3-dihydroxy acetone. 4'-Hydroxymethyl was installed by [3,3]-sigmatropic rearrangement reaction and 1'-methyl group was introduced by carbonyl addition of methylmagnesium bromide. The coupling of nucleosidic bases and desilylation afforded a series of novel nucleosides. The synthesized compounds $16{\~}19$ were evaluated for their antiviral activity against HIV-1, HSV-1, HSV-2, and EMCV. Compounds 16 and 19 exhibit toxicity non-related to any anti-HIV-1 activity.

Surface modification of plastic substrates mediated by silane coupling agents and its application for plastic assembly (use poster) (실란 화합물 기반 플라스틱 기판의 표면 개질화 및 저온 저압 접합 공정)

  • Lee, Nae-Yun
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2013.05a
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    • pp.107-108
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    • 2013
  • 플라스틱 기판 표면을 플라즈마 처리시 형성되는 수산화기에 실란화합물을 반응시키면 상온에서도 플라스틱 표면에 다양한 유기기를 도입할 수 있다. 아민기와 에폭시기가 상온에서도 강력한 화학결합을 이루는 원리를 이용하여, 유기기로써 아미노기와 에폭시기를 갖는 두 실란화합물을 선정, 두 고분자 기판에 각각 도입 후 접합시킨 결과, 저온 및 대기압 조건에서도 강력한 본딩을 이루는 것을 확인할 수 있었다.

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The Effects of Coupling Agent and Crosslinking Agent in the Synthesis of Acrylic Pressure Sensitive Adhesive for Polarizer Film (편광필름용 아크릴 점착제의 합성에서 커플링제와 가교제의 효과)

  • Lim, Chang-Hyuk;Ryu, Hoon;Cho, Ur-Ryong
    • Polymer(Korea)
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    • v.33 no.4
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    • pp.319-325
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    • 2009
  • The solution polymerization was conducted to synthesize pressure sensitive adhesive for polarizer film using acrylic monomers. 2-Ethylhexylacrylate, butylacrylate, acrylic acid were used as acrylic monomers. The ratio was 2-ethylliexylacrylate:butylacrylate:acrylic acid=25:50:3.6 by reflecting $-40^{\circ}C$ of glass transition temperature in the pressure sensitive adhesive. When 1 wt% of coupling agent was added to the polymerized pressure sensitive adhesive, the light transmissivity was significantly increased. This result is due to the enhancement of adhesive power against liquid crystal cell by Si-O bond of coupling agents. Cross-linking agent was added by 0.5, 1.0, and 1.5 wt% with respect to the synthesized polymer. Initial tackiness decreased, while cohesion increased with increasing crosslinking agent. In the analysis of contact angle, the increase of crosslinking agents yielded the enhancement of surface energy, resulting in the decrease of contact angle. From the measurement of heat resistance, the acrylic pressure sensitive adhesive showed excellent heat resistance regardless of change in temperature and contents in crosslinking agent. In the observation of a cutting plane, the increased crosslinking agent represented a smoother and cleaner section. Comprehensively, the optimum additive amount of crosslinking agent was determined to be 1.0 wt% to monomer.

Physical and Chemical Characteristics of Multi-walled Carbon Nanotube (MWCNT) with Acid-treatment and Coupling Agent on the Properties of Styrene Butadiene Rubber (SBR) (SBR에 산 처리된 MWCNT 및 커플링제 적용 시 발현되는 물리.화학적 특성 연구)

  • Song, Sung-Ho;Jeong, Ho-Kyun;Kang, Yong-Gu;Cho, Choon-Tack
    • Polymer(Korea)
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    • v.34 no.2
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    • pp.108-115
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    • 2010
  • The effects of acid-treated MWCNT and coupling agent on properties of MWCNT/SBR are investigated in this work. The MWCNTs oxidized using sulfuric and nitric acids were analyzed by the Raman scattering and Fourier transformed infrared spectroscopy(FT-IR). The FT-IR results indicate the presence of -COOH groups in the treated samples, and Raman spectroscopy of the acidtreated MWCNTs further corroborates the formation of surface defect due to the introduction of carboxyl groups. And the nanocomposites reinforced with MWCNTs were characterized extensively using the scanning electron microscopy(SEM), electrical conductivity, thermal conductivity, and tensile properties measurements. The results showed that nanocomposites onto acid-treated MWCNTs enhanced mechanical properties compared to those containing MWCNTs without acid treatment. These findings confirmed the improved interfacial interactions between MWCNTs and SBR arising from the coupling agents. But the electrical and thermal conductivity of nanocomposites decreased due to the chopping and formation of surface defects of MWCNTs.

Preparation and Characterization of Hard Coating Materials Based on Silane Modified Boehmite Hybrid Materials (Bohemite 나노졸을 이용한 내구성 코팅재료의 제조와 특성에 관한 연구)

  • Jeon, Seong Je;Kim, Woong;Lee, Jai Joon;Koo, Sang Man
    • Applied Chemistry for Engineering
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    • v.17 no.6
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    • pp.580-585
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    • 2006
  • UV-thermal dually curable coating materials were prepared by the sol-gel method. Nano-sized colloidal boehmite was treated with various organo silane coupling agents. These materials could be well dispersed in various alcohols and relatively polar organic solvents such as tetrahydrofuran and acetonitrile. The coating films were prepared by a spin coating method on various substrates, which were characterized by FT-IR, Si/Al CP MAS NMR spectra, UV-Vis spectrophotometer, FE-SEM, Taber abraser, haze meter, and pencil hardness tester. The effects of molar ratio and types of silane coupling agents, curing method and ion-shower treatment were investigated. Dually curable coating method offered an optimally good quality film in both hardness and transmittance. The transparency and the hardness of the prepared films were increased with amounts of 3-(trimethoxysilyl)propylmethacrylate, and (3-glycidyloxypropyl)trimethoxysilane, respectively. The adhesion between coated layer and substrate could be enhanced by ion-shower treatment.

Effect of Addition of Pentaerythritol Triacrylate and Silane Coupling Agents on the Properties of Waterborne Polyurethane (Pentaerythritol Triacrylate와 실란커플링제의 첨가가 수분산 폴리우레탄의 물성에 미치는 영향)

  • Shin, Yong Tak;Hong, Min Gi;Kim, Byung Suk;Lee, Won Ki;Yoo, Byung Won;Lee, Myung Goo;Song, Ki Chang
    • Korean Chemical Engineering Research
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    • v.50 no.2
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    • pp.191-197
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    • 2012
  • Acrylic terminated polyurethane prepolymers were synthesized by capping the NCO groups of polyurethane prepolymers, prepared from isophorone diisocyanate (IPDI), polycarbonate diol (PCD) and dimethylol propionic acid (DMPA), with pentaerythritol triacrylate (PETA). Subsequently, silylated acrylic terminated prepolymers were prepared by capping the NCO groups of acrylic terminated polyurethane prepolymers with different types of silane coupling agents, glycidoxypropyl trimethoxysilane (GPTMS) or aminopropyl triethoxysilane (APS). The average particle size of pure waterborne polyurethane solution, measured by the dynamic light scattering method, was increased from 14.3 nm to 208.6 nm by adding PETA and APS. Also, the coating film of silylated acrylic terminated waterborne polyurethane showed better abrasion resistance and pencil hardness than that of pure waterborne polyurethane.

Removal of Anionic Dyes and Heavy Metal Ions Using Silica Nanospheres or Porous Silica Micro-particles Modified with Various Coupling Agents (다양한 커플링제로 표면 개질된 실리카들을 활용한 음이온성 염료 및 중금속의 제거)

  • Sung, Sohyeon;Lee, Minjun;Cho, Young-Sang
    • Korean Chemical Engineering Research
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    • v.59 no.4
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    • pp.596-610
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    • 2021
  • For application in adsorption process, we synthesized silica nanospheres by Stober method, and silica particles with wrinkled surface as well as macroporous silica particles were also fabricated by utilizing emulsion droplet as micro-reactors, followed by modification of the particle surface using suitable coupling agents containing amine groups. These particles exhibited improved adsorption capacity for heavy metal ions and anionic dyes, which were difficult to be removed by conventional silica particles without surface modification. Anionic dye, methyl orange could be removed almost completely by adsorption using porous silica particles modified using APTES. The adsorption efficiency of heavy metal like copper ions was close to 100%, when porous silica was used as adsorbent particles modified with AAPTS.

A Simulation Method For Virtual Situations Through Seamless Integration Of Independent Events Via Autonomous And Independent Agents

  • Park, Jong Hee;Choi, Jun Seong
    • International Journal of Contents
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    • v.14 no.3
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    • pp.7-16
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    • 2018
  • The extent and depth of the event plan determines the scope of pedagogical experience in situations and consequently the quality of immersive learning based on our simulated world. In contrast to planning in conventional narrative-based systems mainly pursuing dramatic interests, planning in virtual world-based pedagogical systems strive to provide realistic experiences in immersed situations. Instead of story plot comprising predetermined situations, our inter-event planning method aims at simulating diverse situations that each involve multiple events coupled via their associated agents' conditions and meaningful associations between events occurring in a background world. The specific techniques to realize our planning method include, two-phase planning based on inter-event search and intra-event decomposition (down to the animated action level); autonomous and independent agents to behave proactively with their own belief and planning capability; full-blown background world to be used as the comprehensive stage for all events to occur in; coupling events via realistic association types including deontic associations as well as conventional causality; separation of agents from event roles; temporal scheduling; and parallel and concurrent event progression mechanism. Combining all these techniques, diverse exogenous events can be derived and seamlessly (i.e., semantically meaningfully) integrated with the original event to form a wide scope of situations providing chances of abundant pedagogical experiences. For effective implementation of plan execution, we devise an execution scheme based on multiple priority queues, particularly to realize concurrent progression of many simultaneous events to simulate its corresponding reality. Specific execution mechanisms include modeling an action in terms of its component motions, adjustability of priority for agent across different events, and concurrent and parallel execution method for multiple actions and its expansion for multiple events.

The Study of Water Stability of MDF Cement Composite by Addition of Silane Coupling Agent (Silane Coupling Agent 첨가에 의한 MDF Cement Composite의 수분안정성 연구)

  • 노준석;김진태;박춘근;오복진;최상홀
    • Journal of the Korean Ceramic Society
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    • v.35 no.5
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    • pp.421-428
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    • 1998
  • The effect of silane coupling agents on the water stability of HAC/PVA based MDF cement composites which were modified with urethane and epoxy resin were studied as a function of the functional groups and addition amount of silane coupling agent. According to the composition of polymer matrix the silanes with different functional groups showed the different effectiveness. In case of the only PVA matrix the silane with vinyl functional group was more effective than other silanes. When the epoxy resin was added the silane of epoxy-methodxy group enhanced the flexural strength of dry and wet state more than other. In case of urethane-added MDF cement the silane of diamine group was effective and enhanced the water sta-bility fo MDF cement composite more and more as the addition amount of silane increased, Especially in case of warm-presed composite the effect of silane was enhanced By addition of 2wt% of silane with 야-amine group the flexural strength of urethane-added composites were enhanced by 20% more in dry state 40-70% in wet state in accord with the porosity analysis. The flexural strength of the poxy resin-added MDF cement composite was increased by addition of 1wt% and 2wt% silane of epoxy-methoxy group However the addition of 4wt% of silane decreased the flexural strength of dry and wet state by formation of closed pore in the polymer matrix.

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