• Macromolecular Research
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• v.16 no.7
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• pp.614-619
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• 2008

Copolymers of phenyl alkyl acrylates/methacrylates are used clinically as soft materials for the foldable intraocular lens (IOL) to treat cataracts. In this study, copolymers of 2-phenylethyl acrylate (PEA) and 2-phenylethyl methacrylate (PEMA) of various compositions were prepared using free radical polymerization in solution. The composition of the copolymers was determined by $^1H$-NMR analysis. The reactivity ratios of the monomers were calculated using the conventional Fineman-Ross or Kelen-Tudos method. The reactivity ratio of PEA ($r_1$) and PEMA ($r_2$) were estimated to be 0.280 and 2.085 using the Kelen-Tudos method, respectively. These values suggest that PEMA is more reactive in copolymerization than PEA, and the copolymers will have a higher content of PEMA units. The glass transition temperature ($T_g$) of the copolymers increased with increasing PEMA content. The molecular weight and polydispersity indices ($M_w/M_n$) of the polymers were determined by GPC. Overall, these results are expected to be quite useful in applications to foldable soft IOL materials.

• Journal of the Korean Chemical Society
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• v.26 no.4
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• pp.235-246
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• 1982

The free radical polymerization and copolymerization of N-acetyl ${\alpha}$-aminoacrylic acid were investigated. From the result of kinetic investigation of N-acetyl ${\alpha}$-aminoacrylic acid in DMF at $60^{\circ}C$, a rate equation of $R_p$ = $k_p[M]^{0.97}[I]^{0.59}$ was obtained. The overall activation energy for the polymerization was found to be 25.2 kcal/mole. Copolymerization of N-acetyl ${\alpha}$-aminoacrylic acid with acrylic acid and styrene was carried out for the determination of monomer reactivity ratios. The monomer reactivity ratios for the monomer pairs determined at 70.0{\pm}0.1^{\circ}C$ using benzoyl peroxide as an initiator are; $r_1$(N-acetyl ${\alpha}$-aminoacrylic acid) = 0.49, $r_2$(acrylic acid) = 1.41, $r_1$(N-acetyl ${\alpha}$-aminoacrylic acid) = 0.44, $r_2$(styrene) = 0.91. The values of Alfrey-Price's Q and e parameters for N-acetyl ${\alpha}$-aminoacrylic acid were calculated to be 0.51 and 0.16 for the both systems. Differential thermal analysis and thermogravimetry showed that acrylic acid copolymers have poorer thermal stability as compared with the homopolymer of N-acetyl ${\alpha}$-aminoacrylic acid.

• Korean Membrane Journal
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• v.9 no.1
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• pp.57-63
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• 2007

Amphiphilic graft copolymer from poly(vinylidene fluoride) (PVDF) was synthesized using atom transfer radical polymerization (ATRP) for composite nanofiltration membranes. Direct initiation of the secondary fluorinated site of PVDF facilitates grafting of tert-butyl methacrylate (tBMA). Amphiphilic PVDF-g-PMAA graft copolymer with a 51:49 wt ratio was obtained by hydrolyzing poly(tert-butyl methacrylate) (PtBMA) to poly(methacrylic acid) (PMAA). Wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) confirmed the decrease of crystallinity of PVDF upon graft copolymerization. Composite nanofiltration membranes were prepared from PVDF-g-PMAA as a top layer coated onto PVDF ultrafiltration (UF) support membrane. The morphology and hydrophilicity of membranes were characterized using scanning electron microscopy (SEM) and contact angle measurement. The rejections of composite membranes were 80.2% for $Na_2SO_4$ and 28.4% for NaCl, and the solution flux were 9.5 and $14.5\;L/m^2\;h$ at 1.0 MPa pressure.

• Macromolecular Research
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• v.12 no.6
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• pp.593-597
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• 2004

A new ionomeric polymer-metal composite (IPMC) was prepared using a cast membrane of acrylic copolymer, which was synthesized by radical copolymerization of fluoroalkyl acrylate and acrylic acid (AA). To examine its performance as a new electroactive polymer, the current and displacement responses to a step voltage applied across the IPMC were measured. The largest responses were observed when the AA content in the copolymer was $10.6\;wt\%$.

• Textile Coloration and Finishing
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• v.9 no.3
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• pp.27-32
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• 1997

Two poly(4-vinylpyridines) having different degree of crosslinking were prepared by radical copolymerization of 4-vinylpyridine with N, N'-tetramethylenebis-acrylamide as a crosslinker. The abilities of these crosslinked polymers to bind acid dyes (methyl orange, ethyl orange, and propyl orange) were investigated at various temperatures in ethylene glycol as the binding medium. From the equilibrium amounts, the first binding constants and thermodynamic parameters for the bindings were evaluated. The first binding constants and thermodynamic parameters were not varied with these dyes. This result indicates that there is no hydrophobic interaction between the crosslinked polymers and the dyes in ethylene glycol. However, the first binding constants showed bell-shaped curves againtst the binding temperatures. This result could be explained in terms of the crosslinked hole size with temperature variation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.198-201
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• 1994

Stability improvement of fragile LB films was attempted by polyion complexation of monolayers at the air-water interface and crosslinking of the resulting LB films. The spreading polymers were synthesized by radical copolymerization of monoalkyl itaconate with oligoethyleneglycol methyl vinylether, and poly(allylamine) was employed as the subphase polymer. Formation and characteristic of the monolayers were comfirmed by surface pressure-area($\pi$-A) isotherms. The two different polymers formed polyion-complexed monolayer through the formation of carboxylate/ammonium salt at the air-water interface. Y-type deposition occurred on solid substrates, and the transfer ratio was over 0.7. Pores (diameter, 0.1$\mu\textrm{m}$) of a membrane filter could be covered by polyion-complexed 6 layers. Interactions of the polymers with metal ions were investigated of the air-water interface and in the LB films. The structure change and macroscope morphology of the LB films were confirmed by FT-lR and SEM, respective1y.

• Macromolecular Research
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• v.11 no.4
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• pp.273-282
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• 2003

A hydrophilic macromolecular network containing hydrophobic moieties has been prepared by free radical copolymerization of acrylamide and styrene in the presence of poly(vinyl alcohol) (PVA) and its potential as controlled drug delivery carrier was evaluated with tetracycline as a model antibiotic drug. The amount of drug was assayed spectrophotometrically. The network was characterized by optical microscopy, infra-red spectroscopy and structural parameters such as average molecular weight between cross1inks ($M_c$), cross1ink density (q) and number of elastically effective chains ($V_e$) were evaluated. It was found that with increasing concentration of PVA, ST and MBA in the hydrogel, the release rate initially increases but after definite concentrations of the above components the release rate falls. In the case of AM, release rate constantly decreases with increasing AM concentration in the hydrogel.

• Macromolecular Research
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• v.16 no.8
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• pp.670-675
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• 2008

A series of pH and temperature-responsive (N,N-diethylacrylamide-co-methylacrylic acid) copolymers were synthesized by radical copolymerization and characterized by elemental analysis, Fourier-transform infrared (FT-IR), nuclear magnetic resonance (NMR) $^1H$, $^{13}C$ and LLS. The effects of salt and pH on the phase transition behaviors of the copolymers were investigated by uv. With increasing NaCl concentration, significant salt effects on their phase transition behaviors were observed. UV spectroscopic studies showed that the phase transition became faster with increasing NaCl concentration. In addition, the phase transition behaviors of copolymers were sensitive to pH. The pH and temperature sensitivity of these copolymers would make an interesting drug delivery system.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.564-566
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• 2007

Synthesis of two photoactive compounds containing core imide moiety was carried out for an application to interdielectric layer in TFTLCD array. An aqueous alkaline developable polymer matrix was synthesized by free radical copolymerization. A positive photoresist formulation was developed utilizing synthesized UV monomers, photoactive compound, binder polymer, sulfactant and alkali developable polymer matrix. It was found that via-holes with good resolution, high transmittance and thermal resistance could be obtained by photolithographic process utilizing the new positive interdielectric material with high thermal stability.

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.71-76
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• 2006

Porous polymer monolithic columns were prepared by the direct free radical copolymerization of methacrylic acid and ethylene glycol dimethacrylate within the confines of a chromatographic column in the presence of toluene-dodecanol as a porogenic solvent. The separation characteristics of the monolithic columns were tested by a homologous series of xanthine derivatives, theophylline and caffeine. The effects of the polymerization mixture composition and polymerization condition, mobile phase composition, flow rate and temperature on the retention times and separation efficiencies were investigated. The results showed that the selection of correct porogenic solvents and appropriate polymerization conditions are crucial for the preparation of the monolithic stationary phases. The separation efficiency was only extremely weakly dependent on flow rate and temperatures. Hydrogen-bonding interaction played an important role in the retention and separation. Compared with conventional particle columns, the monolithic column exhibited good stability, ease of regeneration, high separation efficiency and fast analysis.