• 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.36 no.2
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• pp.223-228
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• 2012

Temperature and pH sensitive graft copolymers [Pluronic-$g$-poly(NIPAAm-$co$-MMA), Polymer A] and [Pluronic-$g$-poly( NIPAAm-$co$-MAA), Polymer C] were synthesized by macro radical graft polymerization with $N$-isopropylacrylamide (NIPAAM)/$N,N$-diethylaminoethylmethacrylate (DEAEMA) and $N$-isopropylacrylamide (NIPAAm)/methacrylic acid (MAA) based on Pluronic, respectively. The chemical structure and molecular weight of the graft copolymers was characterized by $^1H$ NMR and gel permeation chromatography. The aqueous solution properties of graft copolymers were measured using a UV-visible spectrophotometer, contact angle and dynamic light scattering equipment with different temperature and pH conditions. The obtained graft copolymers showed a very sensitive phase transition in response to temperature and pH in aqueous media which suggested that the amine group of DEAEMA segment and carboxylic group of MAA had a great influence on the lower critical solution temperatures (LCST) in Polymer A and C, respectively. The graft copolymers can be utilized for drug delivery system and molecular switching applications where responses to temperature and pH changes are relevant.

• Bulletin of the Korean Chemical Society
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• v.7 no.2
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• pp.137-142
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• 1986

The luminescence spectra of $Ru(bpy)_3^{2+}$ in poly(methacrylic acid) (PMA) solutions varied sensitively with pH. At pH < 5.5, the emission intensity increased with pH up to 4 times, while it decreased with pH beyond the pH. The enhanced emission intensity was accompanied by blue-shift of the emission maxima as much as 15 nm. The enhancement of emission intensity was attributed to the restricted rotational mobility of ligand of the cation bound to densely coiled PMA molecules at pH < 5.5. The sharp decrease in emission intensity with increasing pH near pH 5.6 was accounted for conformational transition of the polymer to more extended structure, which was also revealed in viscosity measurement. The enhancement of emission intensity became higher as NaCl concentration of the solution increased. The binding constant of $Ru(bpy)_3^{2+}$ with two carboxylate groups of PMA was calculated as $2{\times}10^5\;M^{-1}$ in 0.1 M NaCl at pH 5.2. The pH dependence of luminescence quenching rate of $Ru(bpy)_3^{2+}$ by $Cu^{++}$ also showed maximum near pH 5, and the rate was more than $10^3$ times higher than that in water, whereas the maximum enhancement of quenching rate (about 20 times) in poly(acrylic acid) (PAA) solution occurred at pH 4.5. On the other hand, the pH dependence for neutral water soluble nitrobenzene (NB) exhibited opposite trend to that of $Cu^{++}$. The quenching constant vs pH curve for $MV^{++}$ was composite of those for $Cu^{++}$ and NB. The anomalous high quenching rate for $Cu^{++}$ in PMA solution at pH < 5.5 was attributed to the binding of $Ru(bpy)_3^{2+}$ and $Cu^{++}$ to the same region of PMA, when it conforms densely coiled structure in the pH range. The observation of mininium quenching rate for NB near pH 5.5 indicated that the $Ru(bpy)_3^{2+}$ bound to the densely coiled PMA is not accessible by NB, which is in bulk water phase. The composite nature of the pH dependence of quenching rate for $MV^{++}$ in PMA solution was attributed to the smaller binding affinity of the cation to PMA, compared to that of $Cu^{++}$. The sharp, cooperative conformational transition with pH observed in PMA was not revealed in PAA. But, the pH dependence of quenching rates in this polymer reflected increased charge density and, thus, binding of cations to the polymer, and expansion of the polymer chain with pH.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.299-304
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• 2005

There have been many efforts to use anionic hydrogels as oral protein delivery carriers due to their pH-responsive swelling behavior. The dynamic swelling behavior of poly(methacrylic acid-co-methacryloxyethyl glucoside) [P(MAA-co-MEG)] hydrogels was investigated to determine the mechanism of water transport through these anionic hydrogels. The exponential relation $M_t/M_{\infty}=kt^n$ was used to calculate the exponent, n, describing the Fickian or non-Fickian behavior of swelling polymer networks. The mechanism of water transport through these gels was significantly affected by the pH of the swelling medium. The mechanism of water transport became more relaxation-controlled in the swelling medium of pH 7.0 that was higher than the $pK_a$ of the gels. Experimental results of time-dependent swelling behavior of the gels were analyzed with several mathematical models. Using ATR-FTIR spectroscopy, the effect of ionization of the carboxylic acid groups in the polymer networks on the water transport mechanism was investigated.

• 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 the Korean Chemical Society
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• v.33 no.6
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• pp.662-668
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• 1989

The decomposition reaction of hydrogen peroxide was carried out by using metal-4,4',4",4"'-tetraaminophthalocyanine [Mt-$PcNH_2$, Mt = Fe(III), Co(II)] supported on poly (styrene-co-methacrylic acid), in heterogeneous aqueous system. These catalysts showed a catalse-like activity and Fe(III)-$PcNH_2$ supported on the copolymer was particularly effective for the decomposition of hydrogen peroxide. It was found that the rate of decomposition increased smoothly in the higher pH region and catalytic reaction was interfered by adding $CN^-,\;CNS^-,\;{C_2O_4}^{-2},\;I^-$ ions. The kinetics of the catalytic reaction was also investigated and the reaction proceeds according to the Michaelis-Menten type mechanism.

• Mycobiology
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• v.36 no.4
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• pp.260-265
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• 2008

Cyclic voltammetric measurements were performed for Co(II), Ni(II), Cu(II) and Zn(II) complexes of 1 : 1 alternating copolymer, poly(3-nitrobenzylidene-1-naphthylamine-co-succinic anhydride) (L) and Ni(II) and Cu(II) complexes of 1 : 1 alternating copolymer, poly(3-nitrobenzylidene-1-naphthylamine-co-methacrylic acid) ($L^1$). The in vitro biological screening effects of the investigated compounds were tested against the fungal species including Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans and bacterial species including Staphylococcus aureus, Escherichia coli, Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa by well diffusion method. A comparative study of inhibition values of the copolymers and their complexes indicates that the complexes exhibit higher antimicrobial activity. Copper ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium. The nuclease activity of the above metal complexes were assessed by gel electrophoresis assay and the results show that the copper complexes can cleave pUC18 DNA effectively in presence of hydrogen peroxide compared to other metal complexes. The degradation experiments using Rhodamine B dye indicate that the hydroxyl radical species are involved in the DNA cleavage reactions.

• Nuclear Engineering and Technology
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• v.27 no.1
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• pp.18-24
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• 1995

Characteristics of poly(vinyl alcohol)-poly(methacrylic acid) system (PVA.-PMAA system) for fixation of radioactive contaminant on sand were studied. Dissociation of carboxyl group in PMAA was found to be suppressed by PVA Permeability of sand layer treated with PVA-PMAA solution is directly proportional to the PMAA concentration when the ［PMAA］ is below 0.082 M and the empirical proportional constant (k) is -8.95$\times$10￣$^4$cm$^{5}$ /mole. The change of permeability can be explained by the formation of an intermacromolecular complex between PVA and PMAA The polymer bridge formed on a sand surface combines sand yams more firmly. The PVA-PMAA system is more effective than the PVA system for the fixation of deposited condensational radionuclides.

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.133-147
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• 2005

In order to investigate applicability for 2,2,2-trifluoroethyl methacrylate (TFEMA) produced by esterification of 2,2,2-trifluoroethanol(TFEA) and methacrylic acid(MA) using pervaporation membrane, poly(vinyl alcohol) (PVA) composite membranes were prepared with glutaraldehyde(GA) onto porous polyethersulfone(PES) support. The degree of crosslinking and thickness of PVA coating layer were analyzed by swelling test and SEM(scanning electron microscopy), respectively. Pervaporation test was done with two feed mixures; TFEA/water, MA/water. The pervaporation data were obtained as a function of content of crosslinking agent, feed composition, and operating temperature, respectively. In case of TFEA-water(90/10 wt%) feed mixture at $80^{\circ}C$, the optimized membrane showed the high permeation flux of 1.5 $kg/m^2hr$ and separation factor of 320. In case of MA-water(90/10 wt%) feed mixture, the membranealso showed high permeation flux of 2.3 $kg/m^2hr$ and separation factor of 740 in same conditions.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.367-367
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• 2006

With poly (ethylene-co-methacrylic acid) ionomer (i.e. Surlyn) as a compatibilizer, PP/organoclay (Cloisite(R)20A) nanocomposites were prepared via melt compounding in a co-rotating twin-screw extruder. For comparison, the widely used PP-g-MA was also used as a reference. The content of organoclay was fixed at 5phr based on the total weight of polymer resins. The structures of nanocomposites were characterized by XRD, rheometry in small amplitude oscillatory shear, SEM, and TEM, respectively. It was found that PP/Surlyn/OMMT nanocomposites displayed higher intercalation degree and better dispersion effect than the corresponding PP/PP-g-MA/OMMT counterpart. Additionally, their mechanical properties and wettability were measured.