• Title/Summary/Keyword: dispersity

Search Result 87, Processing Time 0.149 seconds

The Effect of Water and Butanol of Solvent on the Synthesis of Polyisocyanurate in the Presence of Carboxylate Salt Catalyst (카르복실레이트 염 촉매를 사용한 폴리이소시아누레이트의 합성시 용매에 포함된 수분과 부탄올의 영향)

  • Lee, Suk-Jeong;Yang, Hyun-Soo;Choi, Kwang-Sik;Lee, Young-Chul
    • Applied Chemistry for Engineering
    • /
    • v.3 no.4
    • /
    • pp.588-594
    • /
    • 1992
  • Polyisocyanurate has been obtained from toluene diisocyanate(TDI) in the presence of potassium octoate catalyst and the effects of water and butanol in solvent were studied for the determination of the change of viscosity, the reaction time (length of time required for 5 poise of viscosity of product), molecular dispersity of product, and TDI conversion. When butyl acetate contains 0.1% of water by weight, uretidione was formed and a higher conversion was obtained at the condition. The uretidione was not formed by adding butanol to the solvent. At a higher concentration of butanol, a higher TDI conversion and a wider molecular dispersity were obtained.

  • PDF

Dispersity and Electro-Conductivity of PU Grafted MWCNT/PU Composite via Simple Blending Method (블렌딩을 이용한 폴리우레탄 그라프트 다중벽 탄소나노튜브/폴리우레탄 복합체의 전기 전도성 및 분산 특성)

  • Yun, Sung-Jin;Im, Hyun-Gu;Kim, Joo-Heon
    • Applied Chemistry for Engineering
    • /
    • v.21 no.5
    • /
    • pp.500-504
    • /
    • 2010
  • The PU-g-MWNTs/PU film was synthesized by simple blending method to fabricate composites which have excellent mechanical and electrical properties. PU-g-MWNTs based composite revealed much enhanced dispersity than pristine MWNTs composite because of interfacial interaction related with interfacial compatibility between polymer matrix and PU on the MWNTs surface. The electro-conductivity of composite was measured as a function of PU-g-MWNTs concentration. The results were correlated with percolation threshold theory. As a result, the critical concentration and exponent of electro-conductivity behavior was equal to 0.78 wt% and 0.945.

Synthesis of New Black Pigment; Carbon Black Pigment Capsulated into the Meso-pore of Silica as Black Pigment in Cosmetic (새로운 Black Color의 합성;화장품에서 블랙 색소로서 Meso-pore Silca에 캡슐레이션된 Carbon-black Silica)

  • Hye-in, Jang;Kyung-chul, Lee;Hee-chang , Ryoo
    • Journal of the Society of Cosmetic Scientists of Korea
    • /
    • v.30 no.2
    • /
    • pp.189-195
    • /
    • 2004
  • Carbon black have not been used as pigment material in cosmetic because of very low density and dispersity, but carbon black have applicable character as black pigment because of non-toxic, stable physico-chemical property, and black colority. In this study, mesoporous silica samples were synthesized by sol-gel reaction using surfactants-template method; TEOS (tetraethoxysilane) - a) PEO/lecithin, b) PEO/polyethylene glycol, c) lecithin/polyethylene glycol in ethanol/water solution. Synthesized organic-inorganic hybrid - silica were heat-treated in N2 condition at 500$^{\circ}C$. Mesoporous silica with black carbon in pore have the effective density and show the good dispersity in both hydrophilic and hydrophobic solvent. Properties of the samples were measured; specific surface area (750㎡/g) and pore size (4-6nm) using BET, pore structure (cylindrical type) using XRD, morphology (spherical powder with 0.1-0.5$\mu\textrm{m}$ partical size) of the samples using SEM. Carbon-silica black color applied to mascara, it shows a dark black colority and good dispersity as compared with the general black color titania pigment. Moreover, it is possible to control the density of black color pigment because it is possible to control pore volume and particle size of mesoporous silica properly. It show the good volume effects in mascara. That is why possible to apply all kinds of cosmetic products.

Synthesis of Polymeric Dental Restorative Composite Filled with Hydrophobic Silica Nanoparticle (소수성의 실리카 나노입자가 충진된 치아수복용 고분자 복합체 제조)

  • Han, Sanghyuk;Seo, Kitaek;Ma, Seung Jae;Lim, Sang Myung;Kim, Ohyoung
    • Applied Chemistry for Engineering
    • /
    • v.17 no.4
    • /
    • pp.403-408
    • /
    • 2006
  • To enhance the dental properties of polymeric dental restorative composite activated by visible-light, the surface of hydrophilic silica nanoparticle was hydrophobically treated using $\gamma$-methacryloxypropyltrimethoxysilane ($\gamma$-MPS) coupling agent. Structural properties and dispersity of silica in the composite was compared with the hydrophobicity of silica. Polymerization characteristic of the composite was also evaluated. Degree of hydrophobicity of silica nanoparticle was considerably improved with an increase of $\gamma$-MPS upto 40 wt% and converged asymptotically. Additionally, with an increase of the hydrophobicity of silica nanoparticle, the dispersity of silica was improved and the residual monomer in the composite was not detected from nuclear magnetic resonance experiment which indicated superior polymerization behavior.

Dispersion Characteristics of Ag Pastes and Properties of Screen-printed Source-drain Electrodes for OTFTs (Ag Pastes의 분산 특성 및 스크린 인쇄된 OTFTs용 전극 물성)

  • Lee, Mi-Young;Nam, Su-Yong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.21 no.9
    • /
    • pp.835-843
    • /
    • 2008
  • We have fabricated the source-drain electrodes for OTFTs by screen printing method and manufactured Ag pastes as conductive paste. To obtain excellent conductivity and screen-printability of Ag pastes, the dispersion characteristics of Ag pastes prepared from two types of acryl resins with different molecular structures and Ag powder treated with caprylic acid, triethanol amine and dodecane thiol as surfactant respectively were investigated. The Ag pastes containing Ag powder treated with dodecane thiol having thiol as anchor group or AA4123 with carboxyl group(COOH) of hydrophilic group as binder resin exhibited excellent dispersity. But, Ag pastes(CA-41, TA-41, DT-41) prepared from AA4123 fabricated the insulating layer since the strong interaction between surface of Ag powder and carboxyl group(COOH) of AA4123 interfered with the formation of conduction path among Ag powders. The viscosity behavior of Ag pastes exhibited shear-thinning flow in the high shear rate range and the pastes with bad dispersion characteristic demonstrated higher shear-thinning index than those with good dispersity due to the weak flocculated network structure. The output curve of OTFT device with a channel length of 107 ${\mu}m$ using screen-printed S-D electrodes from DT-30 showed good saturation behavior and no significant contact resistance. And this device exhibited a saturation mobility of $4.0{\times}10^{-3}$ $cm^2/Vs$, on/off current ratio of about $10^5$ and a threshold voltage of about 0.7 V.

The Effect of Mercaptoundecanoic Acid (MUA) Coating on Dispersion Property of Au Nanoparticles in Synthesis of Au/TiO2 Core-shell Nanoparticles (Au/TiO2 core-shell 나노입자의 합성에 있어서 Au 나노입자의 분산특성에 미치는 Mercaptoundecanoic acid (MUA)의 피복 효과)

  • Yu, Yeon-Tae;Kim, Byoung-Gyu
    • Korean Journal of Materials Research
    • /
    • v.16 no.12
    • /
    • pp.754-760
    • /
    • 2006
  • Mercaptoundecanoic acid (MUA) has been used to enhance the dispersity of Au nanoparticles in organic solvent and the affinity between the Au nanoparticles surface and titanium dioxide shell in the synthesis of $Au/TiO_2$ core-shell composite nanoparticles. The dispersity of the MUA-coated Au nanoparticles in ethanol aqueous solution with different concentration of $H_2O$ was investigated by UV-Vis. absorption spectrum and the coating amount of MUA was varied from 0.02 mM to 1.0 mM. The MUA-coated Au nanoparticles were highly dispersed in pure $H_2O$ in the wide range of the coating amount of MUA. On the contrary, the MUAcoated Au nanoparticles showed an enhanced stability in the ethanol/$H_2O$=8/2 mixed solution only when the coating amount of MUA was 0.05 mM, and in the ethanol/$H_2O$=7/3 mixed solution when the coating amount of MUA was in the range from 0.02 mM to 0.17 mM. From this systematic study, it can be inferred that the stability and the dispersibility of Au nanoparticles in organic solvents are highly sensitive towards the amount of MUA coating.

INTUMESCENT INORGANIC AND ORGANIC COATINGS

  • Kodolov, V.I.;Mikhalkina, T.M.;Shuklin, S.G.;Bystrov, S.G.;Larionov, K.I.
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
    • /
    • 1997.11a
    • /
    • pp.130-137
    • /
    • 1997
  • Intumescent inorganic and organic coatings which dintr one from the other by the type of gas formers and the mechanisms of foam formation have been obtained and investigated. Inorganic intumescent coatings are the compositions based on water glass and mineral additives with different dispersity. Mineral additives contain adsorbed and absorbed water and carbonates which are destructed with the carbon dioxide and water evolution during the flame action on coating. The decreasing of mineral additives particle sizes under the mechanical milling with the fraction precipitation promotes the foam coke formation with less defects. Here the main structure of comparing compositions does not change. In organic coatings based on epoxy-polymers the polyammonium phosphate additive is used. It is the cabonization catalyst and the foam agent. The polyammonium phosphate of various dispersity employed is uniformly distributed on the polymeric matrix. The decreasing of the particle sizes leads to the increasing of the fire resistant properties of the intumescent coa-ting. The fire resistant analysis of the coating during more than an hour: the coating back side the temperature on plastic or wooden materials does not exceed 423K, and on metal-573K.

  • PDF

Mechanical Properties of Carbon Nanotube/Polyurethane Nanocomposites via PPG Dispersion with MWCNTs (PPG와 탄소나노튜브의 혼합을 통한 탄소나노튜브/폴리우레탄 나노복합체의 기계적 물성)

  • Kim, Dae Won;Kim, Jong Seok
    • Korean Chemical Engineering Research
    • /
    • v.53 no.6
    • /
    • pp.703-708
    • /
    • 2015
  • In order to improve the dispersity of nanofiller, polyurethane (PU) nanocomposites were manufactured via poly(propylene gylcol) (PPG) dispersion with MWCNTs prepared by using a ball mill shaker. MWCNTs could be functionalized by treating with the hydrogen peroxide ($H_2O_2$). Tensile strengths and elongations at break of $PU/H_2O_2$ treated MWCNTs nanocomposites were enhanced compared to those of the PU/pristine MWCNTs nanocomposites. The good dispersion of MWCNTs shown in SEM images was obtained by the functionalization of MWCNTs surface. PU/carbon black (CB) composites showed no significant change in the tensile properties. The tensile properties of PU nanocomposites containing pristine MWCNTs or $H_2O_2$ treated MWCNTs were enhanced with increasing dispersion time. As a result, it was certified that the enhanced dispersity of nanofiller brought the improvement of the tensile properties of the MWCNTs based PU nanocomposites.

Enhancement of Oxygen and Moisture Permeability with Illite-Containing Polyethylene Film

  • Seong, Dong Min;Lee, Hyesun;Chang, Jeong Ho
    • Journal of the Korean Ceramic Society
    • /
    • v.56 no.6
    • /
    • pp.601-605
    • /
    • 2019
  • This work reports the preparation of ceramic hybrid films with illite-polyethylene composites analyzed as a function of concentration of added illite in polyethylene. The enhancement of oxygen and water-vapor transmission rate of illite-polyethylene film was evaluated to determine its influence on the freshness in fruit packaging. Particle size of illite materials was controlled in the range of 1~10 ㎛ and then mixed with LDPE to form the masterbatch. Ceramic hybrid films were prepared through a blown film making process. To determine the dispersity and abundancy of illite materials in the polyethylene matrix, various characterizations of illite-PE hybrid masterbatch and films were performed using SEM, TGA, and FT-IR. The oxygen and water-vapor transmission rate of illite-polyethylene film was found to be two times higher than that of LDPE film.

Preparation and Properties of Liquefied-Wood Polymer Composite (액화목재복합체(LWPC)의 제조 및 물성)

  • Kim, Chul-Hyun;Kim, Kang-Jae;Eom, Tae-Jin
    • Current Research on Agriculture and Life Sciences
    • /
    • v.27
    • /
    • pp.29-33
    • /
    • 2009
  • Liquefied-wood polymer composite was prepared and mechanical properties was evaluated to develop potential utility of liquefied wood. The liquefied wood was made from waste wood and chemical modified with acetic anhydride and maleic anhydride (MA), phtalic anhydride (PA). The composite sheet was prepared from modified liquefied-wood and polymer(PE). The mechanical, chemical and microscopical properties composite sheet were investigated. The results were summarized as follows, 1. The tensile strength was increased and breaking elongation of composite sheet was decreased with the time of acetylation and the dosage of MA. 2. The Young's modulus of composite sheet was gradually decreased with the dosage of PA. 3. The peak intensity of 1737cm-1 in FT-IR spectra of chemical modified liquefied woods was increased. 4. The dispersity of liquefied woods with PE was improved with chemical modification.

  • PDF