• Proceedings of the KOSOMBE Conference
• /
• v.1996 no.11
• /
• pp.281-285
• /
• 1996

Pulsatile swelling behaviors and their application to drug delivery system were studied by using interpenetrating polymer networks(IPN) hydrogels constructed with poly(vinyl alcohol) and poly(acrylic acid). The PVA/PAAc IPNs hydrogels were symthesized by UV irradiation tallowed by repetitive freezing and thawing method. These hydrogels showed pH and temperature sensitive swelling behaviors. From the release experiment, the release amount of model drug incorporated into these hydrogels showed pulsatile patterns. Permeability coefficients obtained by various solutes differed in response to changes of permeation conditions.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2007.11a
• /
• pp.166-168
• /
• 2007

스퍼터링법으로 제작된 FCCL은 PI필름(Poly-imide film)과 Cu layer사이에 Tie-coating layer로 Ni-Cr을 많이 사용한다. 하지만 완성된 FCCL에서 페터닝을 실시할 때 Cr성분이 소멸되지 않고 잔존하는 현상으로 누설전류가 발생 한다. 또한 Cr으로 인해 Eatching액의 오염으로 재사용의 어려움도 발생된다. 이러한 원인들은 제품의 특성들을 저하 시키므로 이를 개선할 필요가 있다. 따라서 본 연구에서는 기존의 Tie-coating layer를 대체할 물질로 Acrylic acid를 이용하여 FCCL을 제작하여 표면특성 평가를 위해 Contact angle측정과 부착력을 위한 Peel test측정과 조직분석 및 성분분석을 위해 SEM-EDS를 측정을 통하여 Polymerization을 이용한 Ti-coating layer 개발의 가능성을 확인하였다.

• Journal of the Korean Wood Science and Technology
• /
• v.25 no.3
• /
• pp.75-82
• /
• 1997

To improve the quality of coated paper, the continuous research to the coating components and development of alternative latices is required. Recently, amphoteric latex is getting a great concern due to their changable properties of surface charge through controlling pH and some methods have been tried to prepare amphoteric latices. This study was carried out to synthesize amphoteric latex using seeding polymerization method with low concentration emulsifier. Styrene was used as a main monomer in addition to acrylonitrile for a hydrophilic comonomer. acrylic acid for a anionic comonomer and N,N-dimethylaminoethyl methacrylate for a cationic comonomer. Particle size and viscosity of latex were greatly affected by addition of acrylic acid and ammonium persulfate as an initiator. Negative charge of latex in alkali condition was changed to zero to positive charge in around pH 4.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.231.1-231.1
• /
• 2003

Mucoadhesive microsphere was prepared by interpo]ymer complexation of po]y(acrylic acid) (PAA) with po]y(vinyl pyrrolidone) (PVP) using solvent diffusion method. The loading efficiency of acetaminophen into the microsphere was 91.3 ${\pm}$ 6.5%. The release rate of acetaminophen from the PAA/PVP complex microspheres was slower than that from PVP microspheres at pH 2.0 and 6.8. The dissolution of microspheres made of the complex was significantly slower than those made of PVP due to H-bond between PVP and PAA. As a result, the release rate of acetaminophen from the complex microspheres was slower than that from PVP microspheres.

• Journal of Adhesion and Interface
• /
• v.11 no.3
• /
• pp.120-125
• /
• 2010

UV-curable acrylic Pressure-sensitive adhesives (Acrylic PSAs) are used in many different parts in the world. A wafer manufacture process which is based on semiconductor industry is one thing. We have used acrylic PSAs whose thickness is different from $20{\mu}m$ to $30{\mu}m$ in wafer manufacture process so far. But as wafers become more thinner, acrylic PSAs are supposed to satisfy the requirements such as proper adhesion performance. The main purpose of this research is studying proper adhesion performance and UV-curing behavior of UV-curable acrylic PSAs with very thin thickness and then determining optimized conditions to raise the efficiency of thin wafer production. Acrylic PSAs contain 2-Ethylhexyl Acrylate (2-EHA), Acrylic Acid (AA) and Butyl Acrylate (BA). Ethyl acetate (EtAc) is used as solvent. The acrylic PSAs are obtained using solvent polymerization. Thickness of UV-curable acrylic PSAs is different from $10{\sim}30{\mu}m$. By peel strength and probe tack, adhesion performance and UV curing behavior of acrylic PSA are concerned.

• Journal of the Korean Applied Science and Technology
• /
• v.24 no.4
• /
• pp.399-409
• /
• 2007

Characteristics of polyaniline anti-corrosive coatings with various primer coating resins(epoxy resin, urethane resin, and others) and top coating resins(epoxy and acrylic urethane resins) were investigated through adhesion, acid resistance, alkaline resistance, water resistance, and anti-corrosion tests. As a result, the anti-corrosive properties of the prepared coatings using polyaniline varied with the types of primer and top coating resins. In this condition, the properties of adhesion, chemical resistance, and water resistance were found to be very satisfactory when using emeraldine base (EB) of polyaniline blended with single-packaged urethane and acrylic urethane resins as the primer coatings, and using acrylic urethane resin as the top coatings. Also, the anti-corrosive function of these anti-corrosive coatings was well preserved for 1000 hr in the salt spray experiment.

• Korean Chemical Engineering Research
• /
• v.51 no.1
• /
• pp.73-79
• /
• 2013

Waterborne polyurethane dispersion (WPUD) was synthesized from polycarbonate diol (PCD), isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as starting materials. Then, waterborne acrylic polyurethane dispersion (AUD) was synthesized by reacting the WPUD with an acrylate monomer, methyl methacrylate (MMA). Subsequently, the AUD was mixed with multi-walled carbon nanotube (MWCNT) to yield a conductive coating solution, and the mixture was coated on the polycarbonate substrate. With increasing the amount of MMA in the AUD, the pencil hardness, abrasion resistance and chemical resistance of the coating films were improved, but the electrical conductivity of the coating films was decreased. On the other hand, the pencil hardness, abrasion resistance and chemical resistance of coating films were decreased, but the electrical conductivity was enhanced with increasing the amount of MWCNT in the conductive coating solutions.

• Korea-Australia Rheology Journal
• /
• v.20 no.3
• /
• pp.109-116
• /
• 2008

The effect of intermolecular aggregation induced by hydrophobic and electrostatic interactions on shear and elongational flow properties of aqueous acrylic thickener solutions is discussed. Complex shear modulus is determined at frequencies up to $10^4$ rad/s employing oscillatory squeeze flow. Extensional flow behavior is characterized using Capillary Break-up Extensional Rheometry. Aqueous solutions of poly(acrylic acid)(PAA)/poly(vinylpyrrolidone-co-vinylimidazole) (PVP-VI) mixtures exhibit unusual rheological properties described here for the first time. Zero-shear viscosity of the mixtures increases with decreasing pH and can exceed that of the pure polymers in solution by more than two orders of magnitude. This is attributed to the formation of complexes induced by electrostatic interactions in the pH range, where both polymers are oppositely charged. PAA/PVP-VI mixtures are compared to the commercial thickener Sterocoll FD (BASF SE), which is a statistical co-polymer including (meth) acrylic acid and ethylacrylate (EA) forming aggregates in solution due to "sticky" contacts among hydrophobic EA-sequences. PAA/PVP-VI complexes are less compact and more deformable than the hydrophobic Sterocoll FD aggregates. Solutions of PAA/PVP-VI exhibit a higher zero-shear viscosity even at lower molecular weight of the aggregates, but are strongly shear-thinning in contrast to the weakly shear-thinning solutions of Sterocoll FD. The higher ratio of characteristic relaxation times in shear and elongation determined for PAA/PVP-VI compared to Sterocoll FD solutions reflects, that the charge-induced complexes provide a much stronger resistance to extensional flow than the aggregates formed by hydrophobic interactions. This is most likely due to a break-up of the latter in extensional flow, while there is no evidence for a break-up of complexes for PAA/PVP-VI mixtures. These flexible aggregates are more suitable for the stabilization of thin filaments in extensional flows.

• Korean Chemical Engineering Research
• /
• v.50 no.3
• /
• pp.410-416
• /
• 2012

Waterborne polyurethane dispersions (PUD) were synthesized from isophorone diisocyanate (IPDI), polycarbonate diol (PCD) and dimethylol propionic acid (DMPA) as starting materials. Subsequently, polyurethane-acrylic hybrid solutions were prepared by reacting the PUD with different types of acrylate monomers, such as HEMA (2-hydroxyethyl methacrylate):MMA (methyl methacrylate), HEMA:BA (butylacrylate), HEMA:BMA (butyl methacrylate), HEMA:HEA (2-hydroxyethyl acrylate), HEMA:PETA (pentaerytritol triacrylate) mixture. Also, the effects of acrylate types on the chemical resistance and the abrasion resistance of polyurethane-acrylic hybrid solutions were investigated. The test results showed that the HEMA:MMA mixture had the strongest chemical resistance, while the HEMA:PETA mixture had the strongest abrasion resistance among several types of acrylate mixtures.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.328.1-328.1
• /
• 2007