• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.253-258
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• 2004

Non-aggregated nanoscale $\alpha$-Al$_2$O$_3$ powders were prepared successfully by polyacrylamine (PAA) gel method. The method was very simple and polymer network inhibited the aggregate of $\alpha$-Al$_2$O$_3$ powders. In this investigation, nanoparticles of $\alpha$-Al$_2$O$_3$ with a diameter of about 8-15 nm were fabricated by calcining the gel precusors with various concentrations of aluminum sulfate, acrylamide and N,N'-methylene-bis-acrylamide (BIS) in air at 110$0^{\circ}C$ for 2 h. The molar ratio of aluminum sulfate to acrylamide did not have any influence on the size of particles. On the other hand, as the molar ratio of BIS to acrylamide increased, the size of nanoparticles decreased.

• Environmental Engineering Research
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• v.11 no.4
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• pp.208-216
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• 2006

In order to create a single flocculant/dual flocculation system, polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride (TAEAC) polymers with varying molecular weights and structures were prepared for use of flocculants. The higher the cationic density of the polymer is higher, the higher was the conversion rate and the ratio of monomer. An acrylamide as nonionic monomer was less reactive than a TAEAC as cationic monomer. The branched polymer which was polymerized with a cross-linking agent, N, N-methylene bis-acrylamide had a higher stability and higher viscosity than a linear polymer but its dewatering efficiency was poor in a single flocculation system. In the case of single flocculant/dual flocculation, the branched polymer has better flocculation efficiency and the water content of the dewatered cakes was lower than the others, as the result of a re-flocculation effect. The optimum conditions for dual flocculation are a sequence in which the $1^{st}$ and $2^{nd}$ dosage are 75% and 25%/total dosage of a single flocculation system. The dewatering efficiency of a dual flocculation system is improved considerably from 10 to 25% under the experimental conditions used herein.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.209-214
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• 1978

Naringinase produced from Aspergillus nidulans was immobilized in acrylamide gel by the entrapping method and its characteristics were studied. Optimum acrylamide concentration was 10%, but N.N'-methylene bisacrylamide concentration had no influence on the final enzyme gel activity. The suitable amount of enzyme dissolved in the polymerization reaction mixture was 126 units/ml. Optimum pH of immobilized enzyme was 5.0 which was the same as that of free enzyme. However, immobilized enzyme showed a higher optumum reaction temperature, markedly increased pH and temperature stability. In a packed-column reactor, the observed reaction rate was increased proportionally to flow rate up to 5ml/min., but independent above 6ml/min.. Activation energy of the immobilized enzyme was 13.01 Kcal/mole, and the energy required for the thermal inactivation was 39.4 Kcal/mole. The apparent Km for 100 mesh gel was $7.23{\times}10^{-3}$ mole.

• Polymer(Korea)
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• v.30 no.4
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• pp.286-292
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• 2006

Super water-absorbent resins were prepared by inverse suspension copolymerization of sodium acrylate, acrylamide and 2-hydroxyethyl acrylate using N, N'-methylene-bis-acrylamide as cross-linker. For the suspension copolymerization, monohexadecyl phosphate was employed as the dispersing agent, cyclohexane as the dispersing medium and potassium persulfate as the initiator. The dependence of water-absorption capacity on the amount of crosslinking agent, oil/water ratio, degree of neutralization and the composition of the copolymer were systematically investigated. Furthermore, the swelling kinetics of the super water-absorbent copolymer was carried out. The absorption of the resins is more than 1800 g/g for deionized water and 100 g/g for 0.9% NaCl solution, respectively. The copolymers showed an increased salt resistance and enhanced water retention of soil.

• Journal of the Korean Ceramic Society
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• v.42 no.3 s.274
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• pp.205-210
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• 2005

Nanoscale silica powder was synthesized from $SiO_2$ precursor solution using Tetraethyl Orthosilicate (TEOS) by polyacrylamide gel method. This process was of simplicity and provided ultrafine powders at relatively low calcination temperatures because polymer network could inhibit aggregation of $SiO_2$ powder. The particle size of Si02 powder was affected by the concentration of ammonium persulphate and N, N'-methylene-bis-acrylamide(BIS) in the gel precursor. The particle size decreased with increasing ammonium persulphate and was mininum size of 10 nm at 0.01 M. Also, the size decreased with increasing BIS concentration and was 5 nm at its concentration of 0.05 M.

• Fibers and Polymers
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• v.5 no.2
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• pp.95-104
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• 2004

A series of superabsorbents based on acrylic acid (AA), sodium acrylate, 2-acrylamido-2-methylpropane sulphonic acid, N,N'-methylene bis-acrylamide (MBA) were prepared by inverse suspension polymerization. These hydrogels were further crosslinked on the surface with polyethylene glycol-600 (PEG-600). The water absorbency or swelling behaviors for these xerogels in water and 0.9% saline solutions, both under free condition and under load were investigated. Absorption characteristics of these hydrogels were found to depend on nature and concentration of crosslinker in the system. It was also found that the saline absorption was significantly improved as the incorporation of AMPS in the polymer was increased. The surface crosslinking introduced in the polymers was found to improve the absorption under load characteristics without lowering the free water absorption capacities of the polymer to a considerable extent.

• Polymer(Korea)
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• v.37 no.6
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• pp.794-801
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• 2013

Novel microgels of N-isopropylacrylamide (NIPAM)-co-methacrylic acid (MAA) (NIPAM-co-MAA) with different contents of N,N-methylene bis acrylamide (MBA) were prepared by emulsion polymerization technique and were studied by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and zeta potential measurement. Effect of pH, temperature and different salts concentration on the microgel particles was investigated. DLS results have shown that the hydrodynamic radius of the microgel increased upon increasing pH and decreased upon increasing temperature. The swelling/deswelling behaviors as determined by DLS showed the ionic repulsions of the carboxyl group of the methacrylic acid and hydrophobic interaction of NIPAM. The effect of various salts on volume phase transition temperature (VPTT) was also investigated. Upon increasing salt concentration, VPTT became broad and shifted to a lower temperature. Electrophoretic mobility measurements showed an increase with increasing pH and temperature at a constant ionic strength.

• The Korean Journal of Mycology
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• v.28 no.1
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• pp.16-21
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• 2000

Super water absorbent (CPAM-AS-hyd-1) was prepared by polymerization of acrylamide and allyl sulfonate salt with N,N'-methylene-bis-acrylamide as crosslinking agent, followed by alkaline hydrolysis and the effect on mycelial growth and sporophore production of edible mushrooms in the artificial cultivation was examined. The mycelial growth of edible mushrooms did not depend on the addition of super water absorbent upto 200 g of hydrated polymer gel per 100 cc medium. The proper hydrated polymer gel concentration for sporophore production of Pleurotus sajor-caju and Hericium erinaceus were 200 g and $200{\sim}250\;g$ per 100 cc medium, respectively. The proper hydrated polymer gel and puffed rice hull concentration for sporophore production of Flammulina velutipes was 200 g per 100 mm medium and 10% (v/v), respectively.