• Journal of Pharmaceutical Investigation
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• v.18 no.2
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• pp.83-88
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• 1988

We examined effects of crosslinking agents, i.e., ethyleneglycol dimethacrylate (EGD) and butanediol dimethacrylate (BDD) containing ester groups on chloromethylation of crosslinked polystyrene resin matrices. It was proved that the ester group in methylmethacrylate (MMA) accelerates the chloromethylation of the divinylbenzene (DVB)-crosslinked styrene-MMA copolymer. As the MMA content increased in the styrene-MMA copolymers, the chloromethylation was enhanced. Complete chloromethylation was obtained at about 25% MMA content.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.87-92
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• 2002

At present, the polymer-modified mortars are used as high-performance as well as multi-functional materials in the construction industry. The purpose of this study is to synthesize polymer to modify in cement mortars and make test samples to understand pore size distribution. This paper deals with the effect of monomer ratio on the typical properties of polymer-modified mortars using Methylmethacrylate-Butyl Acrylate(MMA/BA) latexes synthesized through emulsion polymerization. From the results, we knew that the pore volume of polymer-modified mortars using Methylmethacrylate-Butyl Acrylate latexes at bound MMA contents of 70 and 60 percent is 7.5-75cm$^3$/g and the fine pore volume is increased with an increase in the polymer-cement ratio. The total pore volume of polymer-modified mortars using MMA/BA latexes is linearly reduced with an increase in the bound MMA content and increased in the polymer-cement ratio.

• Polymer(Korea)
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• v.26 no.2
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• pp.245-252
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• 2002

Thermodynamics and gas transport properties of polymethylmethacrylate (PMMA) blends with polyvinylmethylether (PVME) containing various amount of poly (styrene-b-methylmethacrylate) copolymer (P(S-b-MMA)) as a compatibilizer were studied. To extract interaction energies of binary pairs involved in the blends from the phase separation temperatures using an equation-of-state theory, PVME blends with methylmethacrylate copolymers containing various amount of styrene (SMMA) were prepared. PVME formed miscible blends with methylmethacrylate copolymers containing more than 70 wt% styrene and these miscible blonds showed a LCST-type phase separation behavior. Based on the interaction information obtained here, P(S-b-MMA) copolymer was added to the PMMA/PVME blends to enhance their compatibility. The average diameter of the dispersed rubber particles was gradually decreased for the blends of containing P(S-b-MMA) from 0 to 5 phr and then leveled off at a fixed size. At a fixed bland composition, the gas permeation was also increased as the P(S-b-MMA) content increased from 0 to 5 phr and then leveled off when the P(S-b-MMA) content was higher than 5 phr.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.1 s.55
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• pp.35-44
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• 2006

Recently, encapsulation studies have been tarried out to protect active agents using shell materials such as polymers, lipids, inorganic materials and the other protective materials. We have prepared copolymers of methylmethacrylate (MMA) and trimethoxysilylpropylmethacrylate (TMPMA), and the copolymers as shell materials were used for encapsulating active agents. Poly(MMA-co-TMPMA) spheres were very efficient for encapsulating active agents such as vitamin derivatives (such as retinol, retinyl palmitate, tocopheryl acetate and ascorbyl tetraisopalmitate) and oil soluble licorice extract etc. Mean diameters of poly(MMA-co-TMPMA) core-shell spheres containing active agents varied between about 0.1 to $10{\mu}m$ according to the experimental conditions. The loading amount of encapsulating active agents was 15 to 25% (w/w) and the loading yield was above 90%. The stability of active agents in poly(MMA-co-TMPMA) core-shell spheres prepared with an UV absorbing precursor increased by 25% compared with that of active agents in spheres prepared without an UV absorbing precursor.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.421-424
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• 2003

The purpose of this study is to clarify the effect of the emulsifier ratio on strength properties of the polymer-modified mortars using methylmethacrylate-ethyl acrylate(MMA/EA) latexes, and to obtain basic data necessary to develope appropriate latexes for cement modifiers. Polymer-modified mortars using MMA/EA latexes are prepared with various monomer ratios, and tested for air content, flexural and compressive strengths. From the test results, we knew that the water-cement ratio is decreased and the air content is increased with an increase in the amount of emulsifier. In general, the superior flexural and compressive strengths of polymer-modified mortars using MMA/EA latexes is obtained at a bound MMA content of 60 percent and a emulsifier ratio of 6 percent.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.802-808
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• 1994

The purpose of this paper is to describe an application of plasma polymerized thin film as an electron beam resist. Plasma polymerized thin film was prepared using an interelectrode capacitively coupled gas-flow-type reactor, and chosen methylmethacrylate(MMA)and methylmethacrylate-tetrameth-yltin(MMA-TMT) as a monomer. This thin films were also delineated by the electron-beam apparatus with an acceleration voltage of 30kV and an expose dose ranging from 20 to 900$\mu$C/cmS02T. The delineated pattern in the resist was developed with the same reactor which is used for polymerization using an argon as etching gas. The growth rate and etching rate of the thin film is increased with increasing of discharge power. Thin films by plasma polymerization show polymerization rate of 30~45($\pm$3) A/min, and etching rate of 440($\pm$30) A/min during Ar plasma etching at discharge power of 100W. In apparently lower than that of conventional PMMA, but the plasma-etching rate of PP(MMA-TMT) was higher than that of PPMMA.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.273-279
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• 2003

The purpose of this study is to clarify the effect of the monomer ratio on properties of the polymer-modified mortars using methylmethacrylate-butyl acrylate(MMA/BA) latexes, and to obtain basic data necessary to develop appropriate latexes for cement modifiers. From the test results, we knew that the pore volume of polymer-modified mortars using MMA/BA latexes at bound MMA contents of 60 and 70 percent is 7.5∼75nm and the fine pore volume is increased with an increase in the polymer-cement ratio. The total pore volume of polymer-modified mortars using MMA/BA latexes is linearly reduced with an increase in the bound MMA content and increased in the polymer-cement ratio. In general, the superior compressive strength of polymer-modified mortars using MMA/BA latexes is obtained at a bound MMA content of 70 percent and a polymer-cement ratio of 15%. And, the water absorption and chloride ion penetration depth are greatly affected by the polymer-cement ratio rather than the bound MMA content. The important factors affecting the properties of polymer-modified mortars using MMA/BA latexes polymerized with various monomer ratios are the variations of the pore size distribution with changing bound MMA content and the polymer-cement ratio.

• The Journal of Advanced Prosthodontics
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• v.12 no.5
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• pp.322-328
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• 2020

PURPOSE. This study evaluated the shear bond strength between 3D printed provisional resin and conventional provisional resin depending on type of conventional provisional resin and different surface treatments of 3D printed resin. MATERIALS AND METHODS. Ninety-six disc-shaped specimens (Ø14 mm × 20 mm thickness) were printed with resin for 3D printing (Nextdent C&B, Vertex-Dental B. V., Soesterberg, Netherlands). After post-processing, the specimens were randomly divided into 8 groups (n=12) according to two types of conventional repair resin (methylmethacrylate and bis-acryl composite) and four different surface treatments: no additional treatment, air abrasion, soaking in methylmethacrylate (MMA) monomer, and soaking in MMA monomer after air abrasion. After surface treatment, each repair resin was bonded in cylindrical shape using a silicone mold. Specimens were stored in 37℃ distilled water for 24 hours. The shear bond strength was measured using a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were analyzed by scanning electron microscope. Statistical analysis was done using one-way ANOVA test and Kruskal-Wallis test (α=.05). RESULTS. The group repaired with bis-acryl composite without additional surface treatment showed the highest mean shear bond strength. It was significantly higher than all four groups repaired with methylmethacrylate (P<.05). Additional surface treatments, neither mechanical nor chemical, increased the shear bond strength within methylmethacrylate groups and bis-acryl composite groups (P>.05). Failure mode analysis showed that cohesive failure was most frequent in both methylmethacrylate and bis-acryl composite groups. CONCLUSION. Our results suggest that when repairing 3D printed provisional restoration with conventional provisional resin, repair with bis-acryl composite without additional surface treatment is recommended.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.597-602
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• 2013

Background The forehead, which occupies about one third of the face, is one of the major determinants of a feminine or masculine look. Various methods have been used for the augmentation of the forehead using autologous fat grafts or alloplastic materials. Methylmethacrylate (MMA) is the most appropriate material for augmentation of the forehead, and we have used an injection-molding technique with MMA to achieve satisfactory results. Methods Under local anesthesia with intravenous (IV) sedation, an incision was made on the scalp and a meticulous and delicate subperiosteal dissection was then performed. MMA monomers and polymers were mixed, the dough was injected into the space created, and manual molding was performed along with direct inspection. This surgery was indicated for patients who wanted to correct an unattractive appearance by forehead augmentation. Every patient in this study visited our clinics 3 months after surgery to evaluate the results. We judged the postoperative results in terms of re-operation rates caused by the dissatisfaction of the patients and complications. Results During a 13-year period, 516 patients underwent forehead augmentation with MMA. With the injection-molding technique, the inner surface of the MMA implant is positioned close to the underlying frontal bone, which minimizes the gap between the implant and bone. The borders of the implant should be tapered sufficiently until no longer palpable or visible. Only 28 patients (5.4%) underwent a re-operation due to an undesirable postoperative appearance. Conclusions The injection-molding technique using MMA is a simple, safe, and ideal method for the augmentation of the forehead.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.311-311
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• 2006

The morphology of Poly(styrene-b-methylmethacrylate) (P(S-b-MMA)) block copolymer thin films deposited on silicon wafers was controlled by treating the substrates with Self-Assembled Monolayers (SAM) of phenylsilanes with different alkyl chain lengths. It was found that the treatment with SAM strongly modified the substrates properties, especillay the surface energy, as compared with bare silicon oxide. By futher adjusting the molecular weight of P(S-b-MMA), a variety of morphologies could be generated, including a perpendicular orientation of lamellea of PS and PMMA, which is required for industrial applications.