• Journal of the Korean Chemical Society
• /
• v.37 no.4
• /
• pp.431-441
• /
• 1993

The structure and reactivity of ${\pi}$-and metallacycle form in the bis(trimethylphosphine) palladium(0) complexes with acrylic acid, methacrylic acid, crotonic acid(A group) and 3-butenoic acid, 4-pentenoic acid(B group) have been investigated by Molecular Mechanics and Extended Huckel Molecular Orbital method. The calculation shows that A groups with large value of frontier electron density of HOMO and LUMO produce $\pi-complexes$ instead of metallacycle. But B groups with small value of frontier electron density of LUMO, especially 3-butenoic acid, form stable metallacycle. Moreover the methyl-substituted five-membered compared with the six-membered metallacycle is energetically stable conformation.

• Journal of Pharmaceutical Investigation
• /
• v.20 no.1
• /
• pp.13-18
• /
• 1990

Hydrocortisone (HC) sustained-release suppositories were prepared by using a solid matrix of methacrylic acid-methacrylic acid methyl ester copolymer $(Eudragit\;L_{100}^{R}:\;EL)$ as a poorly water soluble carrier and polyethylene glycole 1540 (PEG) as an water soluble carrier. HC release rate was controlled by complexation with ${\beta}-cyclodextrin$ $({\beta}-CyD)$ which was confirmed by X-ray diffractometry, IR-spectroscopy and differential scanning calorimetry. Release rate of HC from the EL-PEG matrix suppositories decreased with increase of EL contents. The release rale from $HC-{\beta}-CyD$ complex decreased in the following order: $HC-{\beta}-CyD/PEG$ > HC/PEG > $HC-{\beta}-CyD/EL_{10%}-PEG$ > $HC/EL_{10%}-PEG$ > $HC-{\beta}-CyD/EL_{15%}-PEG$ > $HC/EL_{15%}-PEG$ > $HC-{\beta}-CyD/EL_{20%}-PEG$ > $HC/EL_{20%}-PEG$. The crystallinity of HC in polymer matrix was identified using X-ray diffractometer and the surface of matrix suppositories after release test was examined by scanning electron microscopy. The sustained release of HC from these matrix suppositories was attributed to the network structure of EL.

• Journal of the Korean Chemical Society
• /
• v.56 no.5
• /
• pp.597-602
• /
• 2012

The copolymerization of triacetoxyvinylsilane, EGDMA (ethylene glycol dimethacrylate as a cross-linker), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), MA (methacrylic acid) was performed in the presence of AIBN (2,2'-azobisisobutyronitrile) as an initiator. Measurement of the physical properties of the resulting copolymers showed that water content, refractive index, visible ray transmittance, and tensile strength were in the range of 35.63~32.44%, 1.4382~1.4480, 89.0~92.5% and 0.346~0.674 kgf, respectively. The values of tensile strength of copolymers-containing hexamethylene diisocyanate were higher than those of the copolymers containing triacetoxyvinylsilane. From the results we came to the conclusion that the produced copolymers are suitable for the application of ophthalmic contact lens with high tensile strength, wettability and duraility.

• Journal of the Korean Chemical Society
• /
• v.55 no.2
• /
• pp.283-289
• /
• 2011

This study used glycerol dimethacrylate with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), MA (methacrylic acid) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Measurement of the physical properties of the copolymerized polymer showed that the water content was 22~32%, refractive index was 1.442~1.463 and visible ray transmittance 90.0~90.5% while the contact angle showed a distribution between 56 and $65^{\circ}$. Also, the measurement showed that the decreased amount of contact angle of the copolymer measured using the sessile drop method ranged between $9.89^{\circ}$ and $18.99^{\circ}$ with increase of glycerol dimethacrylate. Based on the results of this study, the produced copolymer is suitable for use as a material to high wettability ophthalmic lenses.

• Journal of the Microelectronics and Packaging Society
• /
• v.10 no.4
• /
• pp.21-27
• /
• 2003

The copolymers with various composition of methyl methacrylate (MMA), ethyl methacrylate (EMA), methacrylic acid (MA) and hydroxyethyl methacrylate (HEMA) were synthesized for capacitive humidity sensitive materials. The capacitive humidity sensor consisted of a polymethacrylate film coated on both sides with gold electrode. Capacitance versus relative humidity increased with HEMA content in the copolymer. In the case of self-crosslinkable MMA/MA/HEHA= 40/10/10, the average capacitance at 30%RH, 60%RH and 90%RH are 102, 134 and 166 pF, respectively. And also, the hysteresis, temperature cycle and long-term stability were evaluated as a capacitance humidity sensor.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1993.11a
• /
• pp.21-24
• /
• 1993

Many attempts have been made to use hydrogel as del ivory systems for various drug and vioactive materials to prolong and control their pharmacological activities. Rectal administration of drugs by using hydrogel bases, such as poloxamer ABA block copolymer (Pluronic F-127) gels, polyacrylic acid (Carbomer 934, 940, or 941) aqueous gels, and polyvilyl alcohol gels, have been reported on the preparation and potential suppository use of new gels(Eudragit L, Eudragit S, and Eudispert) that are block copolymers of methacrylic acid and methyl methacrylate. If) These hydrogel and xerogel preparations, especially Eudispert hv gels, show excellent staying and bioadhesive effects in the lower part of the rectum in rats and rabbits compared with those of polyethylene glycol (PEG)2000 and Witepsol H-15(or S-55) suppositories. Visual and optical microscopic observation of rectal membrances indicated no irritation or abnormality after administration of Eudispert hv tydrogel and xerogel.

• Korean Chemical Engineering Research
• /
• v.50 no.5
• /
• pp.789-794
• /
• 2012

For the purpose of development of the latex suitable for polymer cement mortar, experiments on the preparation of carboxylated styrene butadiene latex by the method of the two-step emulsion polymerization were performed. Methyl methacrylate, methacrylic acid and acrylic acid were selected as carboxylic co-monomer, styrene and butadiene as monomer, sodium dodecylbenzene sulfonate and sodium salt of lauryl sulfonate as anionic emulsifiers, and nonylphenoxy poly (ethyleneoxy) ethanol (n=10, 20, 40) as latex stabilizer. Potassium persulfate and sodium bisulfite were also used as redox initiator, and sodium monohydrogen phosphate and potassium carbonate as electrolytes. The effects of categories and concentration of carboxylic co-monomer, molecular weight control agent, crosslinking agent, and styrene/butadiene monomer ratio on the characteristics of latex were investigated. Polymerization recipes for preparation of polymer cement mortar could be proposed. The prepared latexes were tested for the physical properties such as compressive and flexural strength when latexes were mixed with cement mortar. The results showed that the latex could be adapted to polymer cement mortar. Also, it was recognized that the compressive and flexural strength were exhibited 25.4% and 45.3% respectively higher improvement than the quality standards at 28 days curing time.

• Journal of Pharmaceutical Investigation
• /
• v.2 no.1
• /
• pp.40-51
• /
• 1972

Water vapor sorption of corn starch in various protective film coated capsules in 100% RH chamber for 14 days were as follows: The percent of water vapor sorption were 28.63% in uncoated capsule, 25.16% in hydroxy propylcellulose(HPC) coated capsule, 15.59% in 2-methyl-5-vinyl pyridine-methyl acrylated-methacrylic acid (MPM) coated capsule and 15.50% in polyvinyl acetal diethyl amino acetate(AEA) coated capsule. 2. Water vapor sorotion of magnesium trisilicate in various protective film coated capsules in 100% RH chamber for 14 days were as follows. The percent of water vapor sorption were 13.91% in uncoated capsule, 13.30% in HPC-coated capsule, 10.87% in MPM-caated capsule and 9.9% in AEA-coated capsule. 3. Water vapor sorption of magnesium carbonate in various protective film coated capsules in 100% RH chamber for 14 days were as follows: The percent of water vapor sorption were 12.48% in uncoated capsule, 10.72% in HPC-coated capsule, 8.10% in MPM coated capsule and 7.8% in AEA-coated capsule. 4. MPM-coated capsules and AEA-canted capsules were mere effective to protect water vapor sorption than HPC-coated capsules.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.11
• /
• pp.1168-1171
• /
• 1998

Two kinds of second-order nonlinear optical copolymers were prepared by the copolymerization of the vinyl monomers containing NLO chromophore, methacrylic acid, and methyl methacrylate or butyl methacrylate. Glass transition temperatures (Tg of copolymers were around 130 ℃. The copolymers were soluble in common organic solvents such as tetrahydrofuran (THF), cyclohexanone, and N,N-dimethylformamide (DMF). The crosslinked copolymer was obtained by thermal treatment using pentaerythritol tetrakis(2-mercaptoacetate) as a crosslinker and became insoluble in tetrahydrofuran (THF) and N,N-dimethylformamide (DMF). Poling was carried out at 120 ℃ for 20 min and identified with UV-Vis spectroscopy. Electro-optic coefficient (r33) measurement showed a value of 35 pm/V for polymer 2 at 633 nm. Temporal stability of copolymers was improved owing to the crosslinked network, which was successfully obtained at 170 ℃ for 30 min after poling.

• Journal of Integrative Natural Science
• /
• v.7 no.1
• /
• pp.5-10
• /
• 2014

A study that copolymerized Ag nanoparticle and furfuryl isocyanate with the crosslinking agent EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), MA (methacrylic acid) and the initiating agent AIBN (azobisisobutyronitrile) is presented. Measurement of the physical characteristics of the produced macromolecule showed that the water content is 32.08~32.67%, refractive index 1.446~1.448, visible light transparency 83.2~67.6%, contact angle $68.2{\sim}83.5^{\circ}$ and tensile strength 0.541~0.755 kgf. It is also demonstrated that the addition of Ag nanoparticles is associated with the reduction of UV-B transmittance and increase in tensile strength. The results show that the produced copolymer can be used as a material for ophthalmic lenses with durability and UV-blocking properties.