• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.101-101
• /
• 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.

• Polymer(Korea)
• /
• v.27 no.1
• /
• pp.17-25
• /
• 2003

Using atom transfer radical polymerization (ATRP), polystyrene macroinitiators and polystyrene-b-poly(t-butyl acrylate) (PS-b-P(tBA) block copolymers were synthesized by CuBr/PMDETA catalyst system in solution. After hydrolysis, polystyrene-b-poly(acrylic acid), amphiphilic block copolymers, were formed. Subsequent neutralization of polyacid block led to the block ionomers. The molecular weight of the synthesized PS-b-P(tBA) block copolymers was easily-controlled to 5000-10000 and their distributions were less than 1.2. The chemical structures of the synthesized block copolymers were characterized by $^1$H-NMR and FT-IR. In the DSC thermograms, $T_g$ appeared in the vicinity of 100 $^{\circ}C$ because of higher styrene content. In addition, the phase separation of the block ionomers was observed by TEM.

• Polymer(Korea)
• /
• v.34 no.4
• /
• pp.306-312
• /
• 2010

Triphenylvinylsilane (TPVS) containing vinyl acetate (VAc), butyl acrylate (BA), and Nmethylolacrylamide (NMA) copolymers were prepared by emulsion polymerization. The polymerization was performed at $80^{\circ}C$ in the presence of auxiliary agents and ammonium peroxodisulfate (APS) as the initiator. Sodium dodecyl sulphate (SDS) and Arkupal N-300 were used as anionic and nonionic emulsifiers, respectively. The resulting copolymers were characterized by using Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and dynamic light scattering (DLS). Thermal properties of the copolymers were studied by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology of copolymers was also investigated by scanning electron microscopy (SEM) and then the effects of silicone concentrations on the properties of the TPVS-containing VAc-acrylic emulsion copolymers were discussed. The obtained copolymers have high solid content (50%) and can be used in weather resistant emulsion paints as a binder.

• Polymer(Korea)
• /
• v.36 no.3
• /
• pp.344-350
• /
• 2012

New pressure sensitive adhesives (PSAs) for polarizer film were prepared by electron beam (e-beam) radiation to acrylic copolymers, and their adhesive properties were investigated. The acrylic copolymers were synthesized by free radical polymerization of $n$-butylacrylate (BA), 2-hydroxyethyl methacrylate (HEMA), and acrylic acid (AA). The acrylic copolymers were coated on PET release films to a thickness of 25 ${\mu}m$, laminated to polarizer films, and then radiated with e-beam at room temperature. Gel fractions of all the acrylic copolymers after e-beam radiation at 50 kGy were higher than 93%, and their crosslinking densities were increased with increasing the content of HEMA units. PSA prepared by e-beam radiation of acrylic copolymer synthesized with a feed ratio of BA/HEMA/AA = 89.5/10/0.5 (w/w/w) at a dose of 50 kGy exhibited the best adhesion performances in terms of peel strength, creep resistance, durability and reliability, and light leakage. It is expected that the preparation method of PSAs via e-beam irradiation will improve the producibility and workability of polarizer film for liquid crystal display.

• Polymer(Korea)
• /
• v.24 no.4
• /
• pp.469-476
• /
• 2000

The miscibility between acrylic copolymers and tackifier resins influenced on adhesion properties of PSA. PSA with high molecular weight and narrow molecular weight distribution of acrylic copolymers showed systemical modification of adhesion properties of PSA by tackifier resins only in case of miscible system. It is concluded that the investigation of the miscibility between two Components is very important to adhesion properties of PSA.

• Bulletin of the Korean Chemical Society
• /
• v.6 no.3
• /
• pp.164-168
• /
• 1985

The fluorescence emission of polystyrene-acrylic acid copolymers containing $Eu^{3+}$ in tetrahydrofuran solution was investigated by spectrofluorimetry. The excimer emission increased linearly with the polymer concentration up to approximately $5{\times}10^{-3}$M. Benzene and toluene collisionally quenched the excimer fluorescence and thier rate constants of quenching were determined. Quenching efficiencies decreased in the order: naphthalene > toluene > benzene. Analyses of Rayleigh scattering and europium emission showed no measurable structural changes observed under the experimental conditions.

• Journal of the Korean Chemical Society
• /
• v.34 no.1
• /
• pp.91-97
• /
• 1990

Copolymers (PSAA) of styrene-acrylic acid were prepared through a free radical mechanism using azobisisobutyronitrile as an initiator. The fluorescence emission spectra of PSAA and the styrene-acrylic acid copolymers complexed with $Eu^{3+}$ (PSAA-Eu) were studied. The excimer fluorescence, centered at 330 nm, increases when the styrene mole fraction increases. Since the excimer fluorescence intensities of PSAA-EU, PSAA-Tb and PSAA-Eu-Tb were almost same, it appears that the kind of metal ion does not affect the excimer fluorescence. An interpretation of the results which takes into account the statistical composition of the copolymers, indicates that energy migration can occur from isolated to non-isolated styrene units.

• Journal of the Korean Applied Science and Technology
• /
• v.13 no.3
• /
• pp.83-94
• /
• 1996

EMA-co-DAMA were synthesized from 2-diethylaminoethyl metacrylate and ethylhexyl metacrylate in acrylmonomer. To facilitate water emulsification, acrylic copolymer was cationized by acetic acid to produce acetated acrylic copolymer. The structures of the synthesized copolymer and acetated copolymers were confirmed by IR, NMR, and molecular weight was measure by GPC, and C.H.N elemental analysis. Acetated acrylic copolymers were perfectly emulsified in water and showed increased emulsion stability. Polymer dispersion for cement modifier[(PDCM-PED) water proof agent of cement for concrete in building construction] was prepared by blending of the guaternized acrylic copolymer syndisized above, sodium silicate, sodium gluconate and oleic acid emulsion. The result with prepared polymer dispersion of cement modifier was examined, and it was found that excellent waterprooffing effect ; Water permeability ratio is 0.50 under the water pressure of $100g/cm^2$ and 0.60 under $3kg/cm^2$, and water absorption ratio is $0.42{\sim}0.50$ and $1.0{\sim}1.02$ compressive strength ratio at mixed of water/PDCM-PED is 50 times.

• Journal of the Korean Chemical Society
• /
• v.56 no.6
• /
• pp.725-730
• /
• 2012

HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate; cross-linker), MMA (methyl methacrylate) and AA (acrylic acid) were copolymerized with ethyl gallate and propyl gallate as additives in the presence of AIBN (2,2'-azobisisobutyronitrile; initiator). The measurement of physical properties of the produced copolymers exhibited that refractive index, water content, visible transmittance, tensile strength, and contact angle were in the range of 1.433-1.435, 38.71-38.99%, 85.4-88.8%, 0.2468-0.2740 kgf and $49.77-36.29^{\circ}$, respectively. The transmittances of the copolymers were measured to be in the range of 49.0-7.4% and 71.0-43.4% for UV-B and UV-A, respectively, indicating that the copolymers have UV-blocking effect. The produced copolymers containing ethyl gallate and propyl gallate satisfied the basic physical properties required for the fabrication of hydrogel contact lenses. The copolymers showed an increase of wettability and UV-blocking effects while having no significant change in water content compared to the gallate-free copolymers.

• Journal of Adhesion and Interface
• /
• v.10 no.3
• /
• pp.134-140
• /
• 2009

The acrylic copolymers with variation in side chain were synthesized based on molecular design. Wettability and adhesion properties on the wafer surface were investigated for these acrylic copolymer pressure sensitive adhesives. Three-dimensional networks of linear acrylic copolymers were produced with epoxy-type Tetra-DX cross-linking agent. The effect of cross-linking on adhesion characteristics was investigated. The side chain of acrylic copolymer played more important role in wettability than the interfacial interaction. As the degree of cross-linking increased, both probe tack and peel strength decreased. Also, heat resistance measured by SAFT increased with cross-linking; however, it showed the deterioration when excess cross-linking agent was added.