• Macromolecular Research
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• v.16 no.8
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• pp.734-740
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• 2008

A new crosslinked, poly(acrylic acid)-based, dehydrating agent was synthesized through solution polymerization. The Taguchi method, a robust experimental design, was adopted to optimize the synthetic conditions based on the moisture and water absorbing capacities of the dehydrating agent. The method applied for the experiment was a standard L27 ($3^8$) orthogonal array with eight parameters and three levels. By analyzing the variance of the test results, the most effective parameters to control the moisture absorbing capacity (MAC) and its rate were the kind of alkaline base (LiOH, NaOH, or KOH) used as a neutralizing agent of the acrylic acid monomer and the degree of neutralization: The maximum MAC of 40% was achieved at only 2 hat $32^{\circ}C$ and 50% RH when KOH was used as a base and the degree of neutralization was 90%, respectively. However, the water absorbing capacity (WAC) of the resulting dehydrating agent was very low at 158 g/g, indicating that WAC is unaffected by MAC and its rate in this system. The surface morphologies of the agents were examined using scanning electron microscopy (SEM).

• Journal of Microbiology and Biotechnology
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• v.19 no.6
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• pp.582-587
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• 2009

Immobilized cells of Arthrohacter nitroguajacolicus ZJUTB06-99 capable of producing nitrilase were used for biotransformation of acrylonitrile to acrylic acid. Six different entrapment matrixes were chosen to search for a suitable support in terms of nitrilase activity. Ca-alginate proved to be more advantageous over other counterparts in improvement of the biocatalyst activity and bead mechanical strength. The effects of sodium alginate concentration, $CaCl_2$ concentration, bead diameter, and ratio by weight of cells to alginate, on biosynthesis of acrylic acid by immobilized cells were investigated. Maximum activity was obtained under the conditions of 1.5% sodium alginate concentration, 3.0% $CaCl_2$ concentration, and 2-mm bead size. The beads coated with 0.10% polyethylenimine (PEI) and 0.75% glutaraldehyde (GA) could tolerate more phosphate and decrease leakage amounts of cells from the gel. The beads treated with PEI/GA could be reused up to 20 batches without obvious decrease in activities, which increased about 100% compared with the untreated beads with a longevity of 11 batches.

• Journal of Adhesion and Interface
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• v.17 no.2
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• pp.56-61
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• 2016

This study was to investigate the effect of main monomer, butyl acrylate instead of 2-ethylhexyl acrylate, of acrylic PSAs on adhesive properties. The copolymers of butyl acrylate, acrylic acid and 2-hydroxyethyl acrylate were synthesized and their adhesive properties were investigated after crosslinking with two different agents. Comparing to 2-hydroxyethyl acrylate-based one which has branch-like side groups, butyl acrylate-based PSA with linear side groups show poor adhesive properties. In case of crosslinking agent, epoxy-typed agent than isocyanate-typed one showed better properties than isocyanate-typed one because epoxy-typed agent has more crosslinking sites and produces more flexible bonds, ester and ether, than isocynate-typed one. Most adhesive properties of PSAs were increased with acid content.

• Journal of Radiation Industry
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• v.9 no.2
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• pp.77-84
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• 2015

The stainless steel mesh coated with poly(acrylic acid) hydrogel was fabricated and applied for the separation of water and oil. The stainless steel mesh was immersed in aqueous poly (acrylic acid) solution, and then irradiated by radiation to introduce poly(acrylic acid) hydrogel on the surface of mesh by crosslinking. It was possible to separate oil and water from mixtures of oil/water effectively using the hydrogel-coated mesh. The effect of irradiation dose, coating thickness, size of mesh on the separation efficiency was examined.

• Journal of Radiation Industry
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• v.5 no.4
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• pp.377-382
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• 2011

Poly(vinyl alcohol) (PVA) is an interesting material with good biocompatibility, high elasticity and hydrophilic chacrateristics. In this study, crosslinked hydrogels based on PVA, and poly(acrylic acid) (PAAc) were prepared by gamma-ray irradiation. PVA and PAAc powders were dissolved in deionized water, and then irradiated by a gamma-ray with a radiation dose of 50 kGy to make hydrogels. The hydrogels were then annealed in an oven at $120^{\circ}C$ for 10 min, 30 min and 50 min under nitrogen atmosphere. The properties of a hydrogel such as gel fraction, swelling behavior, thermogravimetric analysis (TGA) and adhesive strength as a function of PAAc content and annealing time were investigated. The gel fraction decreases with decreasing PAAc content and increasing annealing time. The thermal behaviors have shown different patterns according to the annealing time. The adhesive strength increases with increasing PAAc content.

• Journal of the Korean Chemical Society
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• v.56 no.1
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• pp.92-101
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• 2012

The degradation of one of the commercially important hydrogel based on acrylic acid and acryl amide, (acrylic acid-co-acryl amide) hydrogels, by means of ultrasound irradiation and its combination with heterogeneous ($TiO_2$) was investigated. 24 kHz of ultrasound irradiation was provided by a sonicator, while an ultraviolet source of 16 W was used for UV irradiation. The extent of sonolytic degradation increased with increasing ultrasound power (in the range 30-80 W). $TiO_2$ sonophotocatalysis led to complete (acrylic acid-co-acryl amide) hydrogels degradation with increasing catalyst loading, while, the presence of $TiO_2$ in the dark generally had little effect on degradation. Therefore, emphasis was totally on the sonolytic and sonophotocatalytic degradation of hydrogels and a synergy effect was calculated for combined degradation procedures (Ultrasound and Ultraviolet) in the presence of $TiO_2$ nanoparticles. $TiO_2$ sonophotocatalysis was always faster than the respective individual processes due to the enhanced formation of reactive radicals as well as the possible ultrasound-induced increase of the active surface area of the catalyst. A kinetics model based on viscosity data was used for estimation of degradation rate constants at different conditions and a negative order for the dependence of the reaction rate on total molar concentration of (acrylic acid-co-acryl amide) hydrogels solution within the degradation process was suggested.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.516-522
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• 1998

In this study, a water adsorbent was synthesized by radiation grafting of acrylic acid and multifunctional monomers such as 1,2-propanediol dimethacrylate (PDMA) and 1,1,1-trimethylolethane triacrylate (TMETA) onto cellulose and its subsequent treatment with 5% NaOH. Its absorbency on $H_2O$ and 0.9 % NaCl aqueous solution was examined. The highest absorbency on water and on 0.9% NaCl aqueous solution was obtained from the addition of 0.75 vol % PDDMA and of 1.0 vol % TMETA onto acrylic acid solution, respectively. The absorbency of commercial hygienic band on water and NaCl aqueous solution was 21 g/g and 22 g/g, respectively. However, that for acrylic acid-grafted cellulose including TMETA was 298 g/g and 54 g/g, respectively.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1627-1634
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• 2020

In this study, water-based acrylic adhesives as copolymers with acrylic acid, 2-hydroxyethyl acrylate were synthesized using ethyl acrylate, 2-ethylhexyl acrylate, and lauryl methacrylate as the main monomers. Prepared water-based acrylic adhesive was compared to physical properties such as solid content, average particle size distribution, initial adhesive force, maximum adhesive force, peel strength, and heat resistance.

• Membrane Journal
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• v.13 no.2
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• pp.118-124
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• 2003

The ion exchange membranes prepared from the reaction between poly(vinyl alcohol) (PVA) which is known as the good methanol barrier in pervaporation membrane processes and sulfo-succinic acid (SSA) was used as the basic membranes. In order to improve the ion exchange capacity, poly(acrylic acid) (PAA) was added to this ion exchange membranes. The methanol permeabilities, ion conductivities, water contents and ion exchange capacity were measured for the resulting membranes with varying PAA contents. In general, methanol permeability and ion conductivity of PVA/SSA/PAA membranes were less than those of PVA/SSA membranes due to the reduction of free volumes resulted from crosslinking. The vehicle mechanism could be more dominant than jump mechanism for membranes in question.

• Polymer(Korea)
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• v.33 no.4
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• pp.319-325
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• 2009

The solution polymerization was conducted to synthesize pressure sensitive adhesive for polarizer film using acrylic monomers. 2-Ethylhexylacrylate, butylacrylate, acrylic acid were used as acrylic monomers. The ratio was 2-ethylliexylacrylate:butylacrylate:acrylic acid=25:50:3.6 by reflecting $-40^{\circ}C$ of glass transition temperature in the pressure sensitive adhesive. When 1 wt% of coupling agent was added to the polymerized pressure sensitive adhesive, the light transmissivity was significantly increased. This result is due to the enhancement of adhesive power against liquid crystal cell by Si-O bond of coupling agents. Cross-linking agent was added by 0.5, 1.0, and 1.5 wt% with respect to the synthesized polymer. Initial tackiness decreased, while cohesion increased with increasing crosslinking agent. In the analysis of contact angle, the increase of crosslinking agents yielded the enhancement of surface energy, resulting in the decrease of contact angle. From the measurement of heat resistance, the acrylic pressure sensitive adhesive showed excellent heat resistance regardless of change in temperature and contents in crosslinking agent. In the observation of a cutting plane, the increased crosslinking agent represented a smoother and cleaner section. Comprehensively, the optimum additive amount of crosslinking agent was determined to be 1.0 wt% to monomer.