• Elastomers and Composites
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• 제36권3호
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• pp.195-200
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• 2001

UV조사 하에서 아크릴산의 그라프팅을 이용한 LDPE의 표면개질을 XPS와 접촉각을 이용하여 살펴보았으며, 이에 따른 알루미늄/LDPE 라미네이트의 접착력 변화를 살펴보았다. 접촉각은 UV조사시간이 증가함에 따라 초기에 급격히 감소하다가 점차 일정한 값을 나타내었다. 이는 초기에는 LDPE 표면에 그라프트된 아크릴산에 의해 친수성이 급격히 증가하다가 표면의 아크릴산 농도가 증가함에 따라 친수성의 변화가 상대적으로 감소하기 때문으로 생각된다. 이러한 결과는 XPS를 이용한 O1s/C1s 비의 증가로도 확인할 수 있었다. 아크릴산이 그라프트된 LDPE와 알루미늄의 접착력은 순수한 LDPE를 이용하였을 때에 비하여 약 30배치 증가를 나타내었으며 이는 아크릴간의 그라프트에 의해 LDPF의 표면 극성기가 증가하였기 때문이다. 황산/isodium dichromate를 이용하여 알루미늄 표면을 처리한 경우 보다 뛰어난 접착력을 나타내었다. 아세트산의 존재하에서 LDPE/알루미늄 라미네이트의 계면접착력은 급격히 감소함을 알 수 있었다.

• Macromolecular Research
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• 제17권5호
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• pp.307-312
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• 2009

Core-shell hydrogel nanocomposite was fabricated by encapsulating a silica-gold nanoshell (SGNS) with poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-co-AAc) copolymer. The oleylamine-functionalized SONS was used as a nanotemplate for the shell-layer growth of hydrogel copolymer. APS (ammonium persulfate) was used as a polymerization initiator to produce a hydrogel-encapsulated SGNS (H-SGNS). The amounts of NIPAM (N-isopropylacrylamide) monomers were optimized to reproduce the hydrogel-encapsulated SGNS. The shell-layer thickness was increased with the increase of polymerization time and no further increase in the shell-layer thickness was clearly observed over 16 h. H-SGNS exhibited the systematic changes of particle size corresponding to the variation of pH and temperature, which was originated from hydrogen-bonding interaction between PNIPAM amide groups and water, as well as electrostatic forces attributed by the ionization of carboxylic groups in acrylic acid.

• Journal of Microbiology and Biotechnology
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• 제8권4호
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• pp.347-352
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• 1998

A new strain of Pseudomonas aeruginosa growing in a rice field contaminated with herbicide and effluents of a factory manufacturing explosives was isolated. This isolate showed excellent growth in unusually high concentration of acrylamide (60 mM). It utilized acrylamide as the sole source of carbon and nitrogen for growth. Other amides such as acetamide, butyramide, isobutyramide, and methacrylamide were also utilized for the growth by this isolate. Acrylamide was degraded into acrylic acid and ammonia by the enzyme amidase. More than $65\%$ of added acrylamide (40 mM) was converted into acrylic acid after 40 h of growth of the culture. Amidase activity was inducible, the highest activity being observed with isobutyramide ($12.5{\mu}M$ ammonia/mg protein/min). These results demonstrate that this bacterium can degrade a variety of amides.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.644-647
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• 2000

본 연구에서는 pH 변화에 따른 poly(2-ethyl-2-oxazoline)[PEOx]과 poly(acrylic acid)[PAA]의 수소결합 특성을 고찰하였다. PEOx와 PAA는 산성 조건(pH 4.3이하)하에서 PAA의 수소와 PEOx의 산소간에 수소결합으로 안정한 복합체를 형성하여 침전하였다. PEOx와 PAA 혼합용액을 수성이상계에 적용하기 위한 최적 반응비는 질량비 1:1.5이었고, 이 고분자 혼합용액은 수소결합을 제거한 상태에서 dextran용액과 수성이상계를 형성하였다.

• Membrane and Water Treatment
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• 제6권5호
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• pp.411-422
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• 2015

Membrane modification by different concentrations of acrylic acid has been described. Grafting of acrylic acid to the surface of a polypropylene membrane was obtained by a Fenton-type reaction. Membrane permeability seemed to have been dependent on the value of pH in the solution. To explain tendency, a simple theoretical model was developed. The model incorporates explicitly statistical conformations of a polyacid chain grafted onto the pore surface. The charged capillary model with a varying diameter for porous membranes was then used to evaluate the permeability of the membrane. It has been shown both theoretically and experimentally that the permeability of a grafted membrane depends on the pH of the solution.

• 한국의류산업학회지
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• 제6권3호
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• pp.384-392
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• 2004

The purpose of this study is in development of effective filter-type polymer adsorbent for removal of pollutants from wastewater by UV irradiation graft polymerization. Photografting of acrylic acid (AA) on polypropylene (PP) nonwoven fabric using benzophenone (BP) as a photosensitizer was investigated. Inhibition of homopolymerization was achieved by adding various concentrations of $FeSO_4{\cdot}7H_2O$, $CuSO_4{\cdot}5H_2O$ and Mohr's salt. As AA concentration was increased, the degree of grafting was increased as to a specific value and then decreased, and the effect of BP concentration showed the same tendency. It was also found that the degree of grafting increased with reaction time and reaction temperature. Addition of the polyfunctional monomers and $H_2SO_4$ to the grafting system accelerated the photografting. The melting temperature, molecular weight and breaking stress and breaking strain were decreased with the increase in the degree of grafting.

• Fibers and Polymers
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• 제7권3호
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• pp.223-228
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• 2006

Hydrogels of semi-interpenetrating polymer networks (semi-IPNs) were prepared by two step reactions. Dimethylaminoethyl methacrylate (DMAM) and poly(ethylene glycol)-dimethacrylate (PEGDM) were copolymerized to yield hydrogels, and then acrylic acid (AA) monomer were adsorbed in the hydrogels followed by polymerization of AA to produce semi-IPNs. The swelling behavior of semi-IPNs depends largely on pH of medium, showing that the degree of swelling of the semi-IPNs exhibits a minimum at pH 6.0. It is observed that the elastic modulus of semi-IPNs is closely related to its swelling behavior.

• Archives of Pharmacal Research
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• 제28권5호
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• pp.612-618
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• 2005

A mucoadhesive microsphere was prepared by an interpolymer complexation and solvent evaporation method, using chitosan and poly(acrylic acid) (PAA), to prolong the gastric resid ence time of the delivery system. The Fourier transform infrared results showed that microspheres were formed by an electrostatic interaction between the carboxyl groups of the PAA and the amine groups of the chitosan. X-ray diffraction and differential scanning calorimetry analysis showed that the enrofloxacin in the chitosan-PAA microsphere was molecularly dispersed in an amorphous state. Scanning electron microscopy of the surface and the quantity of mucin attached to the microspheres indicated that chitosan-PAA microspheres had a higher affinity for mucin than those of chitosan alone. The swelling and dissolution of the chitosan-PAA microspheres were found to be dependent on the pH of the medium. The rate of enrofloxacin released from the chitosan-PAA microspheres was slower at higher pH; therefore, based on their mucoadhesive properties and morphology, the chitosan-PAA microspheres can be used as a mucoadhesive oral drug delivery system.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.408.1-408.1
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• 2002

A interpolymer complexes composed of poly(acrylic acid)(PAA) and po!y(vinyl alcohol)(PVA) were prepared by template polymerization of acrylic acid in the presence of PVA for mucoadhesive drug delivery. FT -IR results showed that the PAA/PVA interpolymer complex was formed by hydrogen bonding between the carboxyl groups of PAA and the hydroxyl group of PVA. The dissolution rate or the swelling ratio of the PAA/PVA interpolymer complexes was dependent on the pH and molecular weight of PVA that was used as a template. (omitted)

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.101-101
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• 2006

We have studied the micellisation of poly(n-butyl acrylate)-block-poly(acrylic acid) and poly(n-butyl acrylate)-graft-poly(acrylic acid) in aqueous solution. The size and structure of the formed micelles was elucidated by scattering and imaging techniques. The micelle structure depends on pH, composition, and topology: graft copolymers form much smaller micelles that block copolymers of similar composition. We have also synthesized block copolymers of acrylic acid and N-isopropylacrylamide (NIPAAm) or N,N-diethylacrylamide (DEAAm). Due to the LCST of polyNIPAAm and polyDEAAm, these block copolymers spontaneously form micelles upon heating and they form inverse micelles upon decreasing pH below 4. If the LCST block is much longer than the PAA one, this presents a very convenient way to prepare crew-cut micelles. The polymers have been successfully used as stabilizers in emulsion polymerization. They also have been conjugated to streptavidin. The conjugates reversibly form mesoscopic particles on heating.