• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.93-100
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• 2005

8 functionality photocurable polyester polyol modified hyperbranched methacrylates of two types were prepared from trimellitic anhydride, glycidyl methacrylate, and 4 functionality polyester polyol of two types. The physical properties of photocurable polyester polyol modified hyperbranched methacrylate were investigated. Thermal stability obtained by using TGA showed that HBMA-2 (hyperbranched methacrylate-2) was superior to the HBMA-1 (hyperbranched methacrylate-1). Hardness, abrasion resistance and tensile strength of HBMA-2 showed that were also superior to the HBMA-1. Value of yellow index of HBMA-2 showed the higher.

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.137-144
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• 1996

Durable softening water repellents such as PODCW, PDDCW, and PEDCW were prepared by blending cationized polymers, fatty carbamide, waxes, and emulsifiers. The cationized polymers included poly (octadecyl methacrylate-co-2-diethylaminoethyl methacrylate) [PODC], poly (n-dodecyl methacrylate-co-2-diethylaminoethyl methacrylate) [PDDC]and poly (2-ethylhexyl methacrylate-co-2-diethylaminoethyl methacrylate) [PEDC]. After the PET fabrics were treated with these water repellents, water repellency, softness, and durability of the PET fabrics were examined by various methods : water repellency by the hydrostatic pressure and the contact angle methods, softness by crease recovery and tearing strength, and durability by washability, respectively. Rating of water repellency of PET fabrics treated with PODCW was $80^{+}$, but those treated with PDDCW and PEDCW were not high enough to be used in industry.

• Journal of the Korean Applied Science and Technology
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• v.13 no.2
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• pp.39-46
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• 1996

Durable softening water-repellenting agent such as PODCW, PDDCW and PEDCW were prepared by blending cationized compound such as poly(octadecyl methacrylate-co-2-diethylaminoethyl methacrylate)[PODC], poly(2-dodecyl methacrylate-co-2-diethyl-aminoethyl methacrylate)[PDDC] and poly(2-ethylhexyl methacrylate-co-2-diethyl-aminoethyl methacrylate)[PEDC], and cationized compound of fatty carbamide, of which synthetic methods were reported in the previous paper, waxes, and emulsifiers. The results of physical tests of the P/C blended fabrics treated with PODCW, PDDCW and PEDCW with and without textile finishing resin, showed a remarkable improvement of the physical properties. The prepared water-repellenting agents, PODCW-6 and PDDCW-1, were treated on P/C blended fabrics with and without resin. For any cases, there are a little changes between initial water repellency and repellency after 3 times washing of the fabrics. Therefore, the water-repellenting agents proved to be a durable agents, and initial water $100^{+}$ and $90^{+}$ point, respectively.

• Macromolecular Research
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• v.10 no.2
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• pp.91-96
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• 2002

To explore the effects of intramolecular interactions within the copolymer on the phase separation behavior of polymer blends, copolymers having two different types of intramolecular interactions, i.e., intramolecular repulsion and intramolecular attraction were prepared . In this study, poly(styrene-co-methylmethacrylate) (P(S-MMA)) having intramolecular repulsion caused by positive interaction between styrene and MMA and poly(styrene-co-ethyl-methacrylate) (P(S-EMA)) and poly(styrene-co-cyclohexylmethacrylate) (P(S-CHMA)) having intramolecular attraction caused by negative interaction between styrene and methacrylate were blended with tetramethyl poly-carbonate (TMPC). The phase behavior of blends was examined as a function of copolymer composition and blend composition. TMPC formed miscible blends with styrenic copolymers containing less than certain amount of methacrylate. The phase separation temperature of TMPC blends with copolymer such as P(S-MMA) and P(S-EMA), first increases with methacrylate content, goes through a maximum and then decreases just prior to the limiting content of methacrylate for miscibility, while that of TMPC blends with P(S-CHMA) always decreases. The calculated interaction energy for TMPC-P(S-EMA) pair is negative and monotonically increases with EMA content of the copolymer. Such behavior contradicted the general notion that systems with more favorable energetic interactions have higher LCST, The detailed inspection of the lattice-fluid theory related to the phase behavior was performed to explain such behavior.

• Polymer(Korea)
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• v.26 no.2
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• pp.253-259
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• 2002

The objective of this study is to obtain thermally stable and low optical loss polymers for optical waveguiding materials. The crosslinkable poly (maleimide-co-methacrylate)s were synthesized using a pentafluorophenylmaleimide (an optical loss reducer), two methacrylate derivatives (refractive index controllers), and a glycidylmethacrylate (a crosslinker). These copolymers exhibited good thermal stability and could be thermally crosslinked by heat treatment. The refractive indexes of the copolymers could be precisely controlled by the variation of comonomer feed ratio, which was in the range of 1.45 ~ 1.49. These copolymers had very low birefringence of $6{ imes}10^{-4}$ ~ $1{ imes}10^{-4}$. These copolymers were crosslinked by contact printing and then developed by wet etching to obtain high quality waveguide pattern.

• Journal of Pharmaceutical Investigation
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• v.19 no.3
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• pp.145-154
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• 1989

Methyl methacrylate-butyl methacrylate copolymer (MMBM)-povidone (PVP) films were investigated as a potential topical drug delivery system for the controlled release of econazole nitrate as a model drug. The effect of changes in film composition, drug concentration, film thickness, pH and temperature of release medium on the in vitro release of econazole nitrate were studied. The release rate constant was found to be increased with increasing povidone content in dry films. Drug release followed zero-order kinetics in the initial stage and then release rate increased gradually with time, espicially in the films having larger proportions of PVP. The release rate was found to be dependent on drug content, film thickness, the pH and temperature of release medium. Antimicrobial test showed that microbial growth was inhibited markedly with increasing proportions of PVP in films. Also drug content and film thickness affected the antimicrobial activity.

• Restorative Dentistry and Endodontics
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• v.35 no.1
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• pp.51-58
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• 2010

Dental composites have improved significantly in physical properties over the past few decades. However, polymerization shrinkage and stress is still the major drawback of composites, limiting its use to selected cases. Much effort has been made to make low shrinking composites to overcome this issue and silorane-based composites have recently been introduced into the market. The aim of this study was to measure the volumetric polymerization shrinkage kinetics of a silorane-based composite and compare it with conventional methacrylate-based composites in order to evaluate its effectiveness in reducing polymerization shrinkage. Five commercial methacrylate-based (Beautifil, Z100, Z250, Z350 and Gradia X) and a silorane-based (P90) composites were investigated. The volumetric change of the composites during light polymerization was detected continuously as buoyancy change in distilled water by means of Archemedes' principle, using a newly made volume shrinkage measurement instrument. The null hypothesis was that there were no differences in polymerization shrinkage, peak polymerization shrinkage rate and peak shrinkage time between the silorane-based composite and methacrylate-based composites. The results were as follows: 1. The shrinkage of silorane-based (P90) composites was the lowest (1.48%), and that of Beautifil composite was the highest (2.80%). There were also significant differences between brands among the methacrylate-based composites. 2. Peak polymerization shrinkage rate was the lowest in P90 (0.13%/s) and the highest in Z100 (0.34%/s). 3. The time to reach peak shrinkage rate of the silorane-based composite (P90) was longer (6.7 s) than those of the methacrylate-based composites (2.4-3.1 s). 4. Peak shrinkage rate showed a strong positive correlation with the product of polymerization shrinkage and the inverse of peak shrinkage time (R = 0.95).

• Polymer(Korea)
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• v.38 no.2
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• pp.257-264
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• 2014

In this study, we modified silica nanoparticles with bis[3-(trimethoxysilyl)propyl]ethylenediamine (BTPED) silane coupling agent, which has two secondary amino groups in a molecule, to introduce amino groups on the silica surface. After modification of silica, we used acrylate group containing 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) to introduce polymerizable methacrylate groups by Michael addition reaction. We used Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and liquid and solid state cross polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR) to understand the reactions between N-H groups of BTPED modified silica surface and acrylate groups of AHM monomer. We confirmed Michael addition reaction between BTPED modified silica and AHM completed in 2 hr reaction time. We also found increased methacrylate group introduction with increase of mol ratio of the acrylate group of AHM to N-H group of BTPED modified silica by increase of C=O peak area of measured FTIR spectra. These results were also supported by EA and solid state $^{13}C$ and $^{29}Si$ NMR results.

• Restorative Dentistry and Endodontics
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• v.32 no.3
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• pp.236-247
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• 2007

The purpose of this study was to evaluate the effects of cyanate methacylate on the shear bond strengths to bovine dentin surfaces as a dentin primers. Seven experimental adhesives were made with different mass fraction of Isocyanatoetylme-thacrylate (IEM), 40wt% HEMA (Wako Pure Chemical Industries Osaka, Japan), 0.6% camphoroquinone, 0.4% amine and ethanol as balance dentin bonding agents (0, 2, 4, 6, 8, 10, 12%) were made and applied on the surface of bovine dentin specimens of 7 experimental groups. Shear bond strengths were measured using a universal testing machine (Instro 4466). To identify the ratio and modes of cohesive failures, microscopic examinationn was performed. The ultra-structure of resin tags were observed under scanning electron microscope. The results were as follows ; 1) A higher shear bond strengths (33.62 MPa) in group 8% of Cyanate methacrylate to dentin were found, but there were no statistically significancy between Groups (p > 0.05). 2) The higher ratio of cohesive failures mode in group 2, 6, an 10% could be seen than that in any other groups. 3) A shorter resin tags were observed in all experimental groups. This could be resulted that the preventing from the cyanate methacrylate penetrate into dentin owing to reacting it with dentin collagen. Therefore the resin tags were shorter in lengths. Whether the higher bonding strengths of dentin bonding agents can be affected was not been assured with statistic results. The results indicated that the relation between tensile strengths of the dentin adhesives to bovine dentin and resin tags formed into the dentin could not affected. The main reason of increasing the shear bond strength to bovine dentin in experimental groups could not be assured.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.29-34
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• 2008

Purpose: In this study, we compared the physical properties of the compositions that were mixed with basic materials of HEMA (2-Hydroxyethyl methacrylate)/Silicone and BMA (Butyl methacrylate), MMA (Methyl methacrylate) by making the silicone contact lens. Method: Each sample of contact lenses was fabricated by cast mould method. We analyzed results by using average values of physical property of each sample. Results: In the composition of HEMA/Silicone/BMA, water contents of samples showed the value from 24.69% to 29.26%. Ultimate strength of samples showed the value from 0.109 kgf to 0.263 kgf. In the composition of HEMA/Silicone/MMA, swelling ratio of samples showed the value from 13.56% to 14.83%. Water contents of samples showed the value from 25.61% to 29.33%. Ultimate strength of samples showed the value from 0.107 kgf to 0.286 kgf. Conclusions: The compositions of percents of silicone were ranged from 0.20% to 11.50% and the composition percent of BMA and MMA was 5.15% in total. Swelling ratio and water contents increased with decreasing of BMA (Butyl methacrylate) and MMA (Methyl methacrylate) percent. In the composition of HEMA/Silicone/MMA, the values of ultimate strength increased with increasing of silicone percent to 4-MMA sample. In the composition of HEMA/Silicone/BMA, the values of ultimate strength decreased with increasing of silicone percent.