• 한국인쇄학회지
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• 제20권2호
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• pp.7-18
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• 2002

The emulsification of lithographic printing inks are very important to determine printing quality. In this study, we measured the variation of water pickup according to the hardness of water in dampening solution. In order to observe the rheorogical properties of the emulsified inks, we measured the viscosity, the elastic return, the thixotropy area and yield stress value of the emulsified inks. In this paper, we found that the water pickup of the ink increase the hardness of water with the amount of dampening solution. Also, The viscosity, the yield stress value and the thixotropy area were increase by the water pickup of the ink.

• Journal of Magnetics
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• 제16권2호
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• pp.186-191
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• 2011

[ $YBa_2C_3O_{7-x}$ ]films were fabricated on a $SrTiO_3$ (100) substrate using a trimethylaceate propionic acid (TMAP)-based MOD process by controlling the precursor solution viscosity, firing temperature, and by using various coatings. The viscosity of the precursor solution was controlled by the addition of Xylenes. The films were heat treated with different temperatures from 750 to $800^{\circ}C$. c-axis oriented films were obtained. After adding 9 ml of Xylene into the precursor solution, the $T_c$ of the YBCO film, which was coated 2 times and heat treated at $800^{\circ}C$, was 86 K and the measured $J_c$ was above 2.5 MA/$cm^2$ at 77 K in a zero-field.

• 대한화학회지
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• 제6권1호
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• pp.94-98
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• 1962

The polycondensates of isophthalic acid-cinnamic acid-glycerine system were synthesized. The molecular weights of these products were determined by two methods, viscosity method and osmotic pressure methods. In the synthesis of resin, the reaction temperature was kept at 232$^{\circ}C$ and the mole ratio of the reactants was chosen as follows: Glycerine ;1.0 Isophthalic acid ;1.0 Cinnamic acid ;2.8 Excessive cinnamic acid prevented gelation of reaction mixtures. As the solution became very dilute, reduced osmotic pressure P/C (at the concentration of solution below 0.24g/100 ml of acetone) and reduced viscosity ${\eta}_{sp}/C$ (at the concentration of solution below 0.32 g/100 ml of acetone) increased rapidly. The correspondence between molecular weights determined by the two methods made Huggin's equation applicable to the prepared polymer. The values of K and a are $2.77{\times}10^{-5}$ and 1.063, respectively.

• 대한화학회지
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• 제24권3호
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• pp.209-217
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• 1980

요소 1,3-디메틸요소(DMU), 아세트아미드, 프로피온아미드의 상대점도와 삼투계수를 dimethylsulfoxide(DMSO), 메탄올, 에탄올 및 물용액에서 $25^{\circ}$C와 $45^{\circ}$C에서 각각 측정하였다. 수용액에서 각 용질의 점도증가량은 분몰랄부피가 증가하면서 증가하였으나 물아니 용액에서는 오히려 감소하였다. 또한 요소의 점도 증가량은 수용액에서는 DMU보다 작았으나, 물아닌 용액에서는 DMU보다 컸다. 그러나 아미드류는 어느 용매에서나 거의 같은 점도증가량을 나타내었다. 요소수용액에서 삼투계수는 DMU 수용액보다 컸으며, 물아닌 용액에서 요소용액은 DMU보다 Raoult의 법칙에서 크게 벗어났다. 이러한 사실로부터 요소는 DMSO 용액에서 자체회합을 크게 일으키고 있으며 알코올용액에서는 DMU보다는 큰 정도의 용매-용질상호작용, 수용액에서는 용매구조를 파괴하고 있음을 알았다. 아세트아미드나 프로피온아미드는 수용액이나 DMSO 용액에서보다 알코올용액에서 더 크게 용매구조를 파괴하고 있음을 알았다.

• 보존과학연구
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• 통권34호
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• pp.20-29
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• 2013

지류, 섬유, 목재와 같은 유기질 문화재는 주요 화학성분으로서 셀룰로오스로 구성되어 있다. 셀룰로오스는 글루코오스가 분자내 또는 분자간 수소결합으로 고분자 결정성 구조를 이루고 있다. 특히 셀룰로오스의 중합도는 종이나 섬유의 강도와 밀접한 관련이 있으며, 종이나 섬유에 있어서 열화의 진행정도나 보존성을 나타내는 지표로써 사용된다. 일반적으로 이러한 셀룰로오스의 분자량을 측정하는 방법으로 TAPPI 표준방법인 CED (cupriethylene diamine)용액을 이용한 점도측정법을 많이 사용하고 있다. 목재 섬유로 제조된 종이의 경우 TAPPI 표준 방법 T230법에 의거하여 셀룰로오스 점도를 측정한다. 그러나 우리나라 종이나 섬유의 주요 원료인 닥나무 인피섬유, 저마, 면 등은 목재 셀룰로오스 섬유에 비해 분자량이 크고 중합도가 높아 현재까지 주로 사용되던 T230법으로는 정확한 점도 측정이 어렵다. 따라서 본 연구에서는 고점도 측정방법인 TAPPI 표준 방법 T254법에 의거하여 저농도 CED 용액으로 섬유 깊숙이 용액을 침투시켜 해리시킨 뒤 고농도의 CED 용액으로 완전히 용해시키는 방법을 이용하여 한지의 점도를 측정하였고, 열화시편에 적용하여 종이와 섬유의 열화에 의한 손상정도를 측정하였다.

• Fibers and Polymers
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• 제6권2호
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• pp.103-107
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• 2005

An attempt was made to correlate the polymerization temperature and rheological and thermal properties of acrylonitrile (AN)-acrylamide (AM) copolymers. The copolymers were synthesized at different polymerization temperature. The copolymer structure was characterized by gel permeation chromatography (GPC) and Infrared spectrum (IR). The rheological and thermal properties were investigated by a viscometer and differential scanning calorimeter-thermogrametric (DSC-TG) analysis, respectively. When the polymerization temperature increased from $41^{\circ}C\;to\;65^{\circ}C$, the molecular weight $(\bar{M}_w)$ of copolymers decreased from 1,090,000 to 250,000, while its conversion increased from $18\%\;to\;63\%$, and the polymer composition changed slightly. To meet the requirements of carbon fibers, the rheological and thermal properties of products were also investigated. It was found that the relationship between viscosity and $\bar{M}_w$ was nonlinear and the viscosity index (n) decreased from 3.13 to 2.69, when the solution temperature increased from $30^{\circ}C\;to\;65^{\circ}C$. This suggests the dependence of viscosity upon $\bar{M}_w$ is higher at lower solution temperature. According to the result of activation energy, the sensivity of viscosity to solution temperature is higher for AN-AM copolymers synthesized at higher polymerization temperature. The result of thermal analysis shows that the copolymers obtained at higher polymerization temperature are easier to cyclization evidenced from lower initiation temperature. The weight loss behavior changed irregularly with polymerization temperature due to irregular change of liberation heat.

• Korea-Australia Rheology Journal
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• 제21권2호
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• pp.109-117
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• 2009

Absorption rate of carbon dioxide was measured in the aqueous xanthan gum (XG) solution in the range of 0~0.15 wt% containing diisopropanolamine (DIPA) of $0{\sim}2\;kmol/m^3$ in a flat-stirred vessel with an impeller of 0.05 m and agitation speed of 50 rpm at $25^{\circ}C$ and 101.3 kPa. The volumetric liquid-side mass transfer coefficient ($k_La$) of $CO_2$, which was obtained by the measured physical absorption rate, was correlated with the viscosity and the elastic behavior of XG solution such as Deborah number as an empirical formula. The chemical absorption rate of $CO_2$ ($R_A$), which was estimated by the film theory using the measured $k_La$ and the known kinetics of reaction between $CO_2$ and DIPA, was compared with the measured rate. The aqueous XG solution with elastic property of non-Newtonian liquid made $k_La$ and $R_A$ increased compared with Newtonian liquid based on the same viscosity of the solution.

• Journal of Pharmaceutical Investigation
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• 제33권1호
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• pp.15-19
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• 2003

The rheological behavior of poloxamer 407 solution as function of concentration and temperature was evaluated by rotational viscometer. The viscosity of poloxamer 407 solution was increased as the concentration of poloxamer 407 and temperature increased. At $4^{\circ}C$, poloxamer 407 solution showed the Newtonian flow characteristics regardless of concentration. Upon increasing temperature the poloxamer solution changed to the pseudoplastic flow pattern. And at gelation temperature, rheological profiles showed the abrupt increase in viscosity. Gelation temperature was decreased as the concentration of poloxamer 407 increased, while it increased as the concentration of poly(ethylene glycol) 4000 increased. Poly(ethylene glycol) might be expected to reduce the driving force for hydrophobic interaction resulting in slow gelation. From the viscoelastic properties of poloxamer gel system, we obtained the storage and loss modulus depending on the shear stress and frequency. And the sol-gel transition temperature was also obtained from the viscoelastic properties of poloxamer 407 gel.

• Korea-Australia Rheology Journal
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• 제20권1호
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• pp.1-6
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• 2008

Absorption rate of carbon dioxide was measured in the aqueous xanthan gum (XG) solution in the range of 0-0.15 wt% containing 2-amino-2-methyl-1-propanol (AMP) of $0-2\;kmol/m^3$ in a flat-stirred vessel with an impeller of 0.05m and agitation speed of 50rpm at $25^{\circ}C$ and 0.101 MPa. The volumetric liquid-side mass transfer coefficient ($k_La$) of $CO_2$, which was correlated with the viscosity and the elastic behavior of XG solution containing Deborah number as an empirical formula, was used to estimate the chemical absorption rate of $CO_2\;(R_A)$. $R_A$, which was estimated by mass transfer mechanism based on the film theory using the physicochemical properties and the kinetics of reaction between $CO_2$ and AMP, was compared with the measured rate. The aqueous XG solution with elastic property of non-Newtonian liquid made $R_A$ increased compared with Newtonian liquid based on the same viscosity of the solution.

• 약학회지
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• 제29권5호
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• pp.234-245
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• 1985

To clarify the diffusional behavior of p-aminbenzoic acid esters in the presence of polyethylene glycol 400, cellulose membrane permeation rate, solubility and viscosity of p-aminobenzoic acid methyl ester, benzocaine and butamben were determined with PEG solutions of various concentrations. With an increase in PEG concentrations permeation rates from solutions; decreased due to an increase in viscosity of the solution. From suspensions, however, permeation rates increased due to an increase in solubility and when the initial drug concentration was constant, permeation rates were found to be greatest from the PEG-water system with the PEG concentration which transported from the solution to the suspension. Permeation rate of 4.0mg/ml p-aminobenzoic acid methyl ester was $26.51\mu$g/ml$\cdot$hr from 5g/100ml PEG solution, and that of 4.0mg/ml benzocaine was $13.17{\mu}g/ml{\cdot}hr$ from 15g/100ml PEG, solution, and that of 2.0mg/ml butamben was $3.8{\mu}g/ml{\cdot}hr$ from 10g/100ml PEG solution. Permeation rate was 7.0 fold in p-aminobenzoic acid methyl, ester and 3.5 fold in benzocaine compared to butamben.