• 한국응용과학기술학회지
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• 제20권3호
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• pp.221-229
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• 2003

A copolymer ${\sim}$550cps ; $M_n$, 2590${\sim}$2850 ; and conversion, 82${\sim}$89%, respectively. It was found from the plotting of $T_g$ versus viscosity and $T_g$ versus molecular weight that viscosity increased with $T_g$ while number averaged molecular weight decreased with increasing $T_g$.

• 공업화학
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• 제1권2호
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• pp.133-139
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• 1990

서로 다른 스페이서기를 가지는 메타아크릴레이트 실란을 합성하여, 유리섬유 표면위에서 이들의 흡착거동 및 배향에 관한 FI-IR을 이용하여 연구하였다. 유리섬유/불포화 폴리에스테르 복합재료의 기계적 물성은 유리섬유 표면을 처리한 실란 카플링제의 스페이서기에 의해 크게 영향을 받았다. 실리카 표면에서의 실란 카플링제의 등온 흡착율은 메타아크릴레이트 실란의 메틸렌 스페이서기가 증가함에 따라 감소하였다. 긴 스페이서기를 가지는 실란 분자는 흡착 매체 표면에 활궁처럼 휜상태로 흡착하였다. 유리섬유/불포화 폴리에스테르 복합재료의 고온 습윤 강도를 증진시키기 위해 실란카플링제의 분자 구조와 기계적 물성과의 상관 관계에 대해서도 연구가 병행되었다.

• 대한화학회지
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• 제62권2호
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• pp.93-98
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• 2018

Bis-GMA, TEGDMA, and camphorquinone were used as the main material, cross-linking agent, and photoinitiator, respectively. In addition, 2-isocyanatoethyl methacrylate was used as an additive for high strength, while the 3-hydroxypyridine was used as an additive for antibacterial activity. Photopolymerization was also carried out at a 440-480 nm wavelength and at about $1000mW/cm^2$ intensity for about 40 seconds. The breaking strength measurement of the samples showed that the breaking strength increased along with increasing the addition ratio of IEM, while it took less time until the polymerization was complete, thereby suggesting that the degree of polymerization has the tendency to increase. And also, compared to the size of the clear zone formed by ampicillin, the 3-hydroxypyridine group exhibited antimicrobial activity induced by ampicillin. The results of this study suggest that the use of 2-isocyanatoethyl methacrylate as an additive for high strength and 3-hydroxypyridine as an additive for improved antibacterial activity would improve the usability of the fabricated polymer as a dental resin cement material with high functionality.

• 대한화학회지
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• 제53권3호
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• pp.279-285
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• 2009

This paper has described about preparation of $Zr^{4+}$ affinity column based on the poly(styrene-co- gly-cidyl methacrylate) prepared by emulsion polymerization of styrene and glycidyl methacrylate in order to isolate phosphopeptide. The $Zr^{4+}$ ions were introduced after the phophonation of an epoxy group on polymeric microspheres. The successful preparation of $Zr^{4+}$-immobilized polymeric microsphere stationary phase was confirmed through Fourier transform infrared spectra, optical microscopy, scanning electron microscopy, X-ray photoelectron spectra and inductively coupled plasma-atomic emission spectrometer. The separation efficiency for $Zr^{4+}$ affinity column prepared by slurry packing was tested to phosphonated casein and dephosphonated casein. The resolution time (min) of the phosphonated casein was higher than that of dephosphated casein for $Zr^{4+}$ affinity polymeric microsphere by liquid chromatography. This $Zr^{4+}$ affinity column can be used for isolation of phosphonated casein from casein using liquid chromatography.

• Macromolecular Research
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• 제11권1호
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• pp.14-18
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• 2003

Grafting of glycidyl methacrylate (GMA) upon coralline hydroxyapatite in conjugation with demineralized bone matrix (CHA-DBM) using equal molar ratio of potassium persulfate/sodium metabisulfite redox initiating system was investigated in aqueous medium. The optimum reaction condition was standardized by varying the concentrations of backbone, monomer, initiator, temperature and time. The results obtained imply that the percent grafting was found to increase initially and then decrease in most of the cases. The optimum temperature and time were found to be 50 $^{\circ}C$ and 180 min, respectively, to obtain higher grafting yield. Fourier transform infrared (FT-IR) spectroscopy and X-ray powder diffraction (XRD) method were employed for the proof of grafting. The FT-IR spectrum of grafted CHA-DBM showed epoxy groups at 905 and 853 $cm^{-1}$ / and ester carbonyl group at 1731 $cm^{-1}$ / of poly(glycidyl methacrylate) (PGMA) in addition to the characteristic absorptions of CHA-DBM, which provides evidence of the grafting. The XRD results clearly indicated that the crystallographic structure of the grafted CHA-DBM has not changed due to the grafting reaction. Further, no phase transformation was detected by the XRD analysis, which suggests that the PGMA is grafted only on the surface of CHA-DBM backbone. The grafted CHA-DBM will have better functionality because of their surface modification and hence they may be more useful in coupling of therapeutic agents through epoxy groups apart from being used as osteogenic material.

• Elastomers and Composites
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• 제50권2호
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• pp.110-118
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• 2015

In this study, diethylaminoethyl methacrylate-styrene-butadiene terpolymer (DEAEMA-SBR), in which diethylaminoethyl methacrylate (DEAEMA) was introduced to the SBR molecule as a third monomer, was synthesized by cold emulsion polymerization. It is expected that amine group introduced to a rubber molecule would improve dispersion of silica by the formation of hydrogen bond (or ionic coupling) between the amine group and silanol groups of silica surface. The chemical structure of DEAEMA-SBR was analyzed using proton nuclear magnetic resonance spectroscopy (H-NMR), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). Then, various properties of DEAEMA-SBR/silica composite such as crosslink density, bound rubber content, abrasion resistance, and mechanical properties were evaluated. As a result, bound rubber content and crosslink density of DEAEMA-SBR/silica compound were higher than those of the SBR 1721 composite. Abrasion resistance and moduli at 300% elongation of the DEAEMA-SBR/silica composite were better than those of SBR 1721 composite due to the high bound rubber content and crosslink density. These results are attributed to high affinity between DEAEMA-SBR and silica. The proposed study suggests that DEAEMA-SBR can help to improve mechanical properties and abrasion resistance of the tire tread part.

• The Journal of Advanced Prosthodontics
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• 제1권1호
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• pp.1-5
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• 2009

STATEMENT OF PROBLEM. Poor wettability of denture relining materials may lead to retention problems and patient discomfort. PURPOSE. Purpose of this study is to compare and evaluate wettability of nine denture relining materials using contact angle measurements under air and water storage over time. MATERIAL AND METHODS. Nine denture relining materials were investigated in this study. Two heat-curing polymethyl-methacrylate(PMMA) denture base materials: Vertex RS, Lang, one self-curing polyethyl-methacrylate(PEMA) chairside reline resin: Rebase II, six silicone relining materials: Mucopren soft, Mucosoft, $Mollosil^{{R}}$ plus, Sofreliner Touch, GC $Reline^{TM}$ Ultrasoft, Silagum automix comfort were used in this experiment. Contact angles were measured using high-resolution drop shape analysis system(DSA 10-MK2, KRUESS, Germany) under three conditions(in air after setting, 1 hour water storage, and 24 hours water storage). Nine materials were classified into three groups according to material composition(Group 1: PMMA, Group 2: PEMA, Group 3: Silicone). Mean values of contact angles were compared using independent samples t-test and one-way ANOVA, followed by a Scheffe's post hoc analysis($\alpha$=0.01). RESULTS. Contact angles of materials tested after air and water storage increased in the following order: Group 1(PMMA), Group 2(PEMA), Group 3(Silicone). Heat-cured acrylic denture base resins had more wettability than silicone relining materials. Lang had the highest wettability after 24 hours of water storage. Silicone relining materials had lower wettability due to their hydrophobicity. Wettability of all denture relining materials, except Rebase II and $Mollosil^{{R}}$ plus, increased after 24 hours of water storage. CONCLUSIONS. Conventional heat-cured resin showed the highest wettability, therefore, it can be suggested that heat-cured acrylic resin is material of choice for denture relining materials.

• 한국재료학회지
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• 제20권6호
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• pp.312-318
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• 2010

Multilayer Poly methyl methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates were fabricated using electrospinning and in vitro investigations were carried out for pre-clinical biocompatibility studies. The initial cellular cytotoxicity of the methacrylate (PMMA)/ Poly vinyl alcohol (PVA) bone plates was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay using fibroblast-like L-929 cells. Cellular adhesion and differentiation studies were carried out using osteoblast-like MG-63 cells. As simulated body fluid (SBF) contains the same ionic concentration of body fluid and any bioactive material tends to deposit bone-like apatite on the samples surfaces into the SBF, in vitro bioactivity of the multilayer bone plates were investigated using SBF. We also studied the internal organization and tensile strength of the multilayer PMMA/PVA bone plates using micro-computed topography (${\mu}$-CT) and universal testing instrument (UTI, Korea) respectively. The cellular cytotoxicity study with MTT confirmed that the cellular viability was 78 to 90% which indicates good cyto-compatibility. Scanning electron microscopic findings revealed a good attachment and adhesion phenomenon of MG-63 cells onto the surfaces of the samples. Cellular differentiation studies also showed that osteogenic differentiation was switched on in a timely manner and affirmed along with that of the control group. Bone-like apatite formation on the surfaces was confirmed within 14 days of SBF incubation. Initial organizations of the multilayer PMMA/PVA bone plates were characterized as dense and uniform. The tensile strength of the post-pressing electronspun mat was higher than that of the pre-electronspun mat. These results suggest that a multilayer PMMA/PVA bone plate system is biocompatible, bioactive and a very good alternative bone plate system.

• 폴리머
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• 제24권4호
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• pp.520-528
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• 2000

본 연구는 고형분 70%인 하이솔리드 아크릴 수지 (BMHA)를 합성하여, 환경친화성 도료인 하이솔리드 아크릴/폴리이소시아네이트 도료(BNHS)에 적용하고 그의 도막특성을 살펴본 것에 그 의의가 있다. BMHA는 새로운 형의 단량체로서 acetoacetoxyethyl methacrylate (AAEM)을 도입하고 여기에 n-butyl acrylate, methyl methacrylate 및 2-hydroxyethyl acrylate를 4원공중합시켜 얻었다. BMHA 합성에 있어서 T$_{g}$ 값이 낮을수록, AAEM의 양이 많을수록 각각 높은 전환율을 나타내었고, T$_{g}$값 고정하의 OH 값 변화에 따른 전환율은 큰 차이가 없었다. BMHA와 폴리이소시아네이트를 상온경화시켜 하이솔리드 BNHS 도료를 제조하고서 자동차 상도용 도료로서의 적합성 여부를 알아보기 위하여 도막물성 시험을 한 결과, BNHS내에 AAEM 도입 전후의 도막물성 비교시험에서 AAEM 도입후에 내마모성과 내용제성이 향상됨으로써 자동차 상도용 도료로서의 응용가능성을 보여주었다.다.

• 폴리머
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• 제31권6호
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• pp.550-554
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• 2007

최근 ATRP를 이용하여 단백질에 조절된 구조의 고분자를 연결시키는 연구가 활발히 진행되고 있다. 이때, ATRF 개시제는 단백질에 있는 일차아민에 아미드화 반응을 통하여 도입할 수 있다. 그런데, 형성되는 $\alpha$-할로 아미드의 경우, 상대적으로 늦은 개시 속도를 나타내는 것으로 알려져 있어 원하는 구조의 고분자를 얻는 것이 쉽지 않다. 따라서 본 연구에서는 아미드기를 가지고 있는 개시제를 이용한 [poly(ethylene glycol)methyl ether] methacrylate(PEGMA)의 ATRP 반응에 대한 적절한 반응 조건을 찾고자 하였다. PEGMA는 FEG를 가지로 가지는 단량체로서 고분자로 만들어졌을 때, 물에 잘 녹고 단백질과의 비특이적 상호작용이 적어 단백질과의 결합을 통한 바이오 응용에 널리 사용되고 있다. 아미드기를 가지는 개시제를 이용하여 PEGMA를 성공적으로 중합하기 위한 최적의 중합 조건은 할로겐 교환 반응과 활성 감소제를 사용해서 얻을 수 있었다.