• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2009.04a
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• pp.23-28
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• 2009

The purpose of this study was to improve not only wet-end performances but also paper characteristics by the modification of various factors like molecular design and ionic characteristics of polyacrylamides First of all physical characteristics were observed after modify molecular design of the cationic polyacrylamides to linear, branched and cross-linked. In addition it was found analysis method to confirm branch degree of cationic polyacrylamides to combine ionic titration characteristics and spectroscopic behavior, After application of these structure modified polyacrylamides to the multiple retention systems with inorganic microparticles, it was found adjusting of branch degree of polyacrylamides was very important to optimize wet-end improvement. Second, After polymerization of amphoteric polyacrylamide to have both of cationic and anionic functional group in the polymer, we observed not only physical characteristics but also wet-end improvement to apply recycled pulp and found that the improvement of solution stability to prevent hydrolysis and increase of ash retention dramatically to compare traditional cationic polyacrylamide retention aid, Finally, After polymerization of anionic polyacrylamide, we observed not only wet-end improvement but also paper characteristics to apply preflocculation of PCC and it was found the improvements of flocculation efficiency, retention, ash retention, optical properties of the paper and bursting strength to compare traditional preflocculant of cationic polyacrylamide.

• Macromolecular Research
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• v.17 no.2
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• pp.128-132
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• 2009

Fucoidan, a sulfated polysaccharide derived from brown seaweed, is an important material valued for its various biological functions, including anti-coagulation, anti-aging, and immune system support. In this study, we examined the potential of fucoidan as a novel emulsifying agent in BSA (bovine serum albumin)-stabilized emulsion at a neutral pH. We measured the dispersed oil-droplet size, surface zeta-potential and creaming formation of 0.5 wt% BSA emulsion (20 wt% oil traction) in the absence and presence of fucoidan. The average particle size and zeta-potential value were 625.4 nm and -30.91 mV in only BSA-stabilized emulsion and 745.2 nm and -44.2 mV in 1.0 wt% fucoidan-added BSA emulsion, respectively. This result suggested that some positive charges of the BSA molecules interacted with the negative charges of fucoidan to inhibit the flocculation among the oil droplets. The creaming rate calculated from the backscattering data measured by Turbiscan dramatically decreased in 1.0 wt% fucoidan-added BSA emulsion during storage. Accordingly, the repulsion forces induced among the oil particles coated with 1.0 wt% fucoidan in emulsion solution resulted in significantly increased emulsion stability. The turbidity of the BSA-stabilized emulsion at 500 nm decreased during five days of storage. However, the fucoidan-added BSA emulsion exhibited a higher value of turbidity than the BSA-stabilized emulsion did. In conclusion, an anionic sulfated fucoidan lowered the surface zeta-potential of BSA-coated oil droplets via the electrostatic interaction, and subsequently inhibited the flocculation among the oil droplets, thereby clearly minimizing the creaming and phase separation of the emulsion.

• Journal of the Korean Chemical Society
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• v.20 no.2
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• pp.158-165
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• 1976

The anionic polymerization of ${\varepsilon}$-caprolactam with N,N'-adipyl-bis-${\varepsilon}$-caprolactam as an initiator and potassium hydroxide as a catalyst was studied under various conditions.It was found that concentration of catalyst and initiator was 4.2 and 1.6 mole %, and polymerization temperature of 130$^{\circ}C$C, polymerization time of 1.5 hours was the optimum condition. The intrinsic viscosity and molecular weight of the obtained polymer was over 0.9 dl/g and 12,000. The polymerization was carried out in the presence of N-acyl-${\varepsilon}$-caprolactam as an initiator, it was observed that the reactivity of N,N'-adipyl-bis-${\varepsilon}$-caprolactam was greater than both of the N-benzoyl-${\varepsilon}$-caprolactam and N-acetyl-${\varepsilon}$-caprolactam. In general it was also observed that the intrinsic viscosity and yield of conversion was increased as an increasing of concentration of catalyst and initiator and also highly depend on temperature.

• Polymer(Korea)
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• v.36 no.6
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• pp.727-732
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• 2012

Baroplastic poly(butyl acrylate) (PBA)/polystyrene (PS) blends were prepared by mixing PBA and PS emulsions synthesized by cationic and anionic surfactant, respectively. Interestingly, the heterocoagulation of nanoparticles have found to be affected strongly by emulsion concentration but the blends have been prepared with almost same compositions regardless of the amount of reactants. Utilizing this method, PBA/PS/Si hybrid nano-blends were prepared successfully via electrostatic attraction forces between PBA, PS and silica nanoparticles. The hybrid nano-blend having 2 or 5 wt% of silica was then processed to a semi-transparent film at $25^{\circ}C$ under 13.8 MPa for 10 min, which showed 3.0 MPa of tensile strength and 25 MPa of elastic modulus. Therefore, the heterocoagulation technique can be used for preparing baroplastics with uniform compositions of polymer and silica nanoparticles.

• Polymer(Korea)
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• v.30 no.6
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• pp.550-555
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• 2006

The coating material for the ink-jet printing paper tends to be waterbase as the waterbase ink-jet ink is used more widely. Waterbase coating material consists of alumina sol as a pigment, poly(vinyl alcohol) as a main binder and polymeric additive for improving properties. In this study, polymeric auditive was synthesized by combining one or toto monomers among methacrylic acid, acrylic acid and acrylamide to the basic monomers, styrene and n-butylacrylate. The properties of printability such as ink absorption, ink spreading, and optical density, glossiness and water resistance were investigated by changing the kinds of surfactants, the composition of monomers and the structure of polymer particles. Results showed that materials containing anionic surfactant and/or acrylic acid had problems in com-patibility with alumina sol. Also, coating materials containing acrylamide had good printability and lout glossiness while those containing methacrylic acid did not have good printability and high glossiness.

• Polymer(Korea)
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• v.37 no.5
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• pp.587-591
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• 2013

Poly(3,4-ethylenedioxythiophene) (PEDOT) has good properties such as high conductivity, optical transmittance, and chemical stability, while offering relatively weak physicochemical properties. The main purpose of this paper is the improvement of physicochemical properties such as solvent resistance and pencil hardness of PEDOT. Carboxyl groups in the anionic type waterborne polyurethane (WPU) chains can effectively crosslink each other in the presence of aziridine, resulting in physicochemically robust PEDOT/WPU organic-organic hybrid conductive thin films. The electrical conductivity, optical properties, and physicochemical properties of the hybrid conductive film were compared by varying the solid content and WPU portion in the coating precursor solution. From the results, the transparency and surface resistance of the hybrid film show a decreasing tendency with increasing solid content in the coating precursor. Moreover, solvent resistance and hardness were dramatically enhanced by hybridization of PEDOT and crosslinked WPU due to curing reactions between carboxyl groups.

• Journal of the Korean Chemical Society
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• v.59 no.4
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• pp.271-279
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• 2015

The critical micelle concentration (CMC), the counter ion binding constant (B) and the aggregation number (N^* ) for the mixed micellization of sodium dodecanoate and sodium n-octanoate as two anionic surfactants have been investigated by means of electric conductivity and light scattering. As its experimental results are found to be deviated from ideal mixed model, thus two different kinds of regular solution models such as Rubingh and Motomura are used for interpreting our experimental data. The stability of the mixed micelles has been confirmed from the negative values of the standard Gibbs energy of mixed micellization ΔG^micel,0 over all compositions and the measured values of ΔG^micel,0 agreed with the theoretical ones within the experimental error.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.527-534
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• 2006

The purpose of this study is the development of more effective filter-type polymer adsorbent for removal of anionic pollutants from wastewater. In order to synthesize the polymer adsorbent that possesses anionic exchangeable function, carboxyl(-COOH) group of PP-g-AA nonwoven fabric was converted into amine($-NH_2$) group by the chemical modification using diethylene triamine(DETA). FT-IR data indicate that amine group was introduced into PP-g-AA through amidation of grafted acrylic acid by reaction with DETA. The degree of amination increased with increase in the reaction time and temperature of the chemical modification process, and was significantly improved by the pre-swelling treatment of PP-g-AA with solvent and addition of metal chlorides as a catalyst in following order as $NH_4OH>MeOH{\geq}HCl{\geq}H_2O\;and\;AlCl_3>FeCl_3{\geq}SnCl_2{\gg}ZnCl_2{\geq}FeCl_2$, respectively. However, the addition of catalyst limited the reusability of DETA, hence was less useful from the viewpoint of cost effectiveness and waste management. The anion exchange capacity of the aminated PP-g-AA(PP-g-AA-Am) increased with increase in the degree of amination, but it reached maximum value at the degree of amination as about $50{\sim}60%$. The anion exchange capacity of PP-g-AA-Am was higher than those of commercial anion resins.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.789-794
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• 2012

For the purpose of development of the latex suitable for polymer cement mortar, experiments on the preparation of carboxylated styrene butadiene latex by the method of the two-step emulsion polymerization were performed. Methyl methacrylate, methacrylic acid and acrylic acid were selected as carboxylic co-monomer, styrene and butadiene as monomer, sodium dodecylbenzene sulfonate and sodium salt of lauryl sulfonate as anionic emulsifiers, and nonylphenoxy poly (ethyleneoxy) ethanol (n=10, 20, 40) as latex stabilizer. Potassium persulfate and sodium bisulfite were also used as redox initiator, and sodium monohydrogen phosphate and potassium carbonate as electrolytes. The effects of categories and concentration of carboxylic co-monomer, molecular weight control agent, crosslinking agent, and styrene/butadiene monomer ratio on the characteristics of latex were investigated. Polymerization recipes for preparation of polymer cement mortar could be proposed. The prepared latexes were tested for the physical properties such as compressive and flexural strength when latexes were mixed with cement mortar. The results showed that the latex could be adapted to polymer cement mortar. Also, it was recognized that the compressive and flexural strength were exhibited 25.4% and 45.3% respectively higher improvement than the quality standards at 28 days curing time.

• Journal of Adhesion and Interface
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• v.13 no.3
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• pp.109-115
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• 2012

Monodisperse blue-colored poly(styrene-co-acrylic acid) latices were successfully prepared by seeded emulsion polymerization. Blue-colored latices with carboxyl anionic charge on the surface were synthesized at the second stage with the introduction of Blue 606 dye, acrylic acid, and 0.21 ${\mu}m$-polystyrene seed. All the blue-colored latices synthesized in this study were in the size range of 0.25~0.42 ${\mu}m$ and all uniform with less than 1.01 in PSD. The particle size increased with the addition of acrylic acid being delayed and colloidally stable latices were obtained over 30 min after its addition. The blue-colored latex with 20 wt% acrylic acid showed -145 mV of zeta-potential and $-9.4{\times}10^{-6}\;cm^2/Vs$ of electrophoretic mobility, and with 25 wt% of DVB showed high $T_g$ at 396.7 K.