• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.105-109
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• 2010

HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate) and propylene glycol was copolymerized in the presence of AIBN (azobisisobutyronitrile) initiator in a mould. The physical properties of the contact lens were measured. The water content of 37.06~38.71%, refractive index of 1.492~1.432, visible transmittance of 89.4~91.5%, tensile strength of 0.1416~0.2302 kgf, and contact angle of $38.60{\sim}53.53^{\circ}$ were obtained. Therefore, the contact lens material produced using propylene glycol as an additive satisfied the basic physical properties required for contact lenses application. It is interesting to note that an increase in wettability and tensile strength while having no significant changes in water content.

• Journal of the Korean Applied Science and Technology
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• v.32 no.2
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• pp.202-214
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• 2015

Stimuli-responsive biomaterials that alter their function through sensing local molecular cues may enable technological advances in the fields of drug delivery, gene delivery, actuators, biosensors, and tissue engineering. In this research, pH-responsive hydrogel which is comprised of dimethylaminoethyl methacylate (DMAEMA) and 2-hydroxyethyl methacrylate (HEMA) was synthesized for the effective delivery of doxorubicin (Dox) to breast cancer cells. Cancer and tumor tissues show a lower extracellular pH than normal tissues. DMAEMA/HEMA hydrogels showed significant sensitivity by small pH changes and each formulation of hydrogels was examined by scanning electron microscopy, mechanical test, equilibrium mass swelling, controlled Dox release, and cytotoxicity. High swelling ratios and Dox release were obtained at low pH buffer condition, low cross-linker concentration, and high content of DMAEMA. Dox release was accelerated to 67.3% at pH 5.5 for 6-h incubation at $37^{\circ}C$, while it was limited to 13.8% at pH7.4 at the same time and temperature. Cell toxicity results to breast cancer cells indicate that pH-responsive DMAEMA/HEMA hydrogels may be used as an efficient matrix for anti-cancer drug delivery with various transporting manners. Also, pH-responsive DMAEMA/HEMA hydrogels may be useful in therapeutic treatment which is required a triggered release at low pH range such as gene delivery, ischemia, and diabetic ketoacidosis.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.755-760
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• 2010

This study used 3-vinylanisole and 4-vinylanisole with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), NVP (N-vinyl-2-pyrrolidone) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Measurement of the physical characteristics of the copolymerized material showed that the refractive index is 1.4496 - 1.4894, water content 22.93 - 35.50%, visible transmittance 88.8 - 90.8%. Also, measurements showed that the refractive index increased while the water content decreased as the ratio of 3-vinylanisole and 4-vinylanisole increased. And in cases of copolymer with 3-vinylanisole, 4-vinylanisole (added 15%) the results showed transmittance of 52.8 - 82.2%, 13.2 - 26.2% respectively for UV-A and UV-B showing that they have UV-blocking effects. Based on the results of this study, the produced copolymer can be estimated to be suitable for use as ophthalmic lens material for high refractive index and UV- blocking effects.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.761-765
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• 2010

Poly (N,N-dimethylacrylamide) is very useful in various fields due to its remarkable properties, such as water solubility and biocompatibility. This study used N,N-dimethylacrylamide with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), NVP (N-vinyl-2-pyrrolidone) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Measurement of the physical properties of the copolymerized polymer showed that the water content was 36 - 42%, refractive index was 1.433 - 1.426 and visible ray transmittance 90 - 91% while the oxygen permeability showed a distribution between 13.1 and $21.29{\times}10^{-11}(cm^2/sec)$ ($mlO_2/mL{\times}mmHg$). The measurement showed that the increased amount of oxygen permeability of the copolymer measured using the polarographic method range between 11.0% and 80.5%. Based on the results of this study, the produced copolymer is suitable for use as a material to high oxygen permeability hydrogel lenses.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.1
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• pp.49-53
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• 2006

Acrylate -PDMS(Polydimethylsiloxane)-Urethane Prepolymer is synthesized through treating diisocynate, HEMA(2-hydroxyethylmethacrylate) and bis(hydroxyalkyl)terminated Poly(dimethylsiloxane) having high oxygen permeability under the DBTDL(Dibutylitin dilaurate) catalyst. Modification of HEMA on bis(hydroxyalkyl)terminated Poly(dimethylsiloxane) is to be able to polymerize with other contact lens materials. And modification of urethane on bis(hydroxyalkyl)terminated Poly(dimethylsiloxane) is to increase elastic property and oxygen transmissibility. This material is analyzed by FT-IR and also will be used to make hydrogel contact lens.

• Bulletin of the Korean Chemical Society
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• v.5 no.5
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• pp.175-178
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• 1984

Two series of membranes have been prepared by postcrosslinking highly syndiotactic and isotactic poly (2-hydroxyethyl methacrylate), P(HEMA). The crosslinker used was hexamethylene diisocyante (HMDIC). The distribution coefficients (K$_{D2}$) of the model solutes such as urea (and thiourea), their derivatives, homologous alcohol series and amide sreies in water-swollen tactic P(HEMA) membranes at $25^{\circ}C$ were mesaured. In addition, the concentration effects of acetamide and butyramid were also measured. On the basis of hydrophobic interaction and the structural factors of tactic P(HEMA) membranes, the hydrophobic adsorption of the solutes in the polymer matrix were discussed. The results showed that the more hydrphobic the solute is, the higher the $K_{D2}$ value is. And the polymer conformation also affects the distribution of solvents.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.99-104
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• 2010

Platinum nanoparticles were added to a mixture of HEMA (2-hydroxyethyl methacrylate), NVP (N-vinyl pyrrolidone) and MMA (methyl methacrylate) in a mould at various concentrations. The resulting mixture was copolymerized by heating at $70^{\circ}C$ for 40 min, $80^{\circ}C$ for 40 min, and $100^{\circ}C$ for 40 min, respectively. The physical properties of contact lens were then measured. The oxygen transmissibility of $9{\sim}15{\times}10^{-9}$ cm/s mL $O_2$/mL ${\times}$ mmHg, water content of 34.22~35.52%, refractive index of 1.432~1.435, visible transmittance of 88.3~91.2% and tensile strength of 0.141~0.152 kgf were obtained. The addition of platinum nanoparticles to the polymer allowed the contact lens to have various colors without artificial coloring agents. The polymer materials satisfied the physical properties required to produce contact lenses, making the material suitable to be applied as a functional material for ophthalmological purposes.

• Journal of Biomedical Engineering Research
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• v.8 no.1
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• pp.13-28
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• 1987

Crosslinked poly(2-hydroxyethylmethacrylate) has been prepared by polymerizing 2-hydroxyethyl methacrylate(HEMA) with crosslinkers such as ehyleng glycol dime- thacrylate(EGDMA), tetraethylene glycol dimethacrylate(TEGDMA), tetraethylene glycol diacrylate(TEGDA), divinyl benzene(DVB), and N, N-methylenebisacry- lamide(MAB) in the presence of initiator $\alpha$ , $\alpha$ -azobisisobutyronitrile at 60。C, The synthesized copolymers were identified by FT-lR spectrophotomether. The swelling properties of the crosslinked copolymers in various solvents such as water, methanol, ethanol, n-propanol, and n-butanol were investigated at different temperatures. The thermal properties of the crosslinked coplymers were also measured by differential scanning calorimetry(DSC) and thermogravimetry(TG)

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.725-730
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• 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 the Korean Chemical Society
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• v.56 no.5
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• pp.597-602
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• 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.