• Bulletin of the Korean Chemical Society
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• 제22권12호
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• pp.1337-1340
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• 2001

The bulk photopolymerization of methyl methacrylate (MMA) with para-substituted phenylsilanes such as F-C6H4SiH3 (1), H3C-C6H4SiH3 (2), and H3CO-C6H4SiH3 (3) was performed to produce poly(MMA)s containing the respective silyl moiety as an end group. For all the hydrosilanes, the polymerization yields and the polymer molecular weights decreased, whereas the TGA residue yields and the relative intensities of Si-H IR stretching bands increased as the relative silane concentration over MMA increased. The polymerization yields and polymer molecular weights of MMA with 1-3 increased in the order of 3 < 1 < 2. These hydrosilanes influence significantly upon the photopolymerization of MMA as both chain-initiation and chain-transfer agents.

• 한국의류학회지
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• 제15권3호
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• pp.271-280
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• 1991

Emulsion graft copolymerization of MMA onto cotton fiber using Ce(IV) salt as an initiator was carried out. Graft yield and graft efficiency were observed according to the kinds and concentrations of emulsifier and polymerization conditions. The physical properties of MMA grafted cotton fabric were investigated. The results of this study were as follows: 1. The heighest graft yield of emulsion graft polymerization occurred at the concentration below cmc of emulsifier, which was different from emulsion polymerization. Nonionic sur- factant as an emulsifier was more effective than anionic one. 2. The highest graft yield was obtained at the initiator concentration $1{\times}10^{-2}mol/l$. The viscometric molecular weight of PMMA was in the order of 106. 3. As reaction time increased, the graft yield increased but the graft efficiency decreased. 4. Elevation of reaction temperature resulted in increase of graft yield. The apparent activation energy of MMA graft polymerization was 4.72 Kcal/mol. 5. Physical properties of MMA grafted cotton fabric varied with increase of grafting. Thickness and stiffness showed a noticeable increase, whereas tensile strength and elongation was slightly increased. Crease recovery increased as the graft yield increase up to $50\%$ and decreased thereafter.

• 대한전기학회논문지
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• 제43권5호
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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.

• 공업화학
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• 제4권2호
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• pp.300-307
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• 1993

$Na_2S_2O_4$ 수용액과 $CCl_4$-toluene 용액의 2상에서 유기상에 용해하는 tricaprylmethylammonium chloride 상이동 촉매를 사용하여 methyl methacrylate의 라디칼 중합속도를 측정하여, 액-액 불균일계 접촉계면을 통한 라디칼 중합반응기구를 해석하였다. MMA의 중합속도는 수용액상에 존재하는 $Q^+$ 이온의 농도와 ${S_2O_4}^{-2}$ 이온의 농도의 제곱근에 정비례하고 $CCl_4$와 MMA의 농도에 각각 정비례하였다.

• Macromolecular Research
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• 제15권5호
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• pp.418-423
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• 2007

A methacrylate copolymer based on isobornyl methacrylate (IBMA) and methyl methacrylate (MMA) was synthesized in an aqueous suspension via free-radical polymerization. The potential of this copolymer as a heat-resistant optical polymer is also discussed. 1,1,3,3-tetramethylbutyl peroxy-2-ethyl hexanoate and n-octyl mercaptan were used as the initiator and chain transfer agents, respectively. The effect of IBMA on the properties of the copolymer was investigated. The composition of the copolymer was analyzed using $^1H-NMR$, and the heat resistance by measuring the glass transition temperature, which exhibited a linear dependency on the IBMA content in the copolymer. Variation of the chain transfer content used in the synthesis step was effective for the optimization of the copolymer for practical use.

• 대한화학회지
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• 제19권1호
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• pp.53-64
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• 1975

Co$Cl_2$-THF-MMA계에 대한 중합반응을 조사한 결과 다음과 같은 사실을 알았다. 즉 중합시간에 따른 중합변화율이 6${\sim}$7% 미만의 초기에는 직선적인 관계가 있으나 차차 중합속도가 감소했다가 그 후에는 라디칼중합의 경우와 같이 자동가속화현상을 볼 수 있었다. 개시물인 염화 코발트(II)의 농도가 증가하면 중합속도가 증가했다가 약 $3.4{\times}10^{-4}$mole/l 이상이 되면 반대로 중합속도는 감소하였다. 그리고 단위체인 MMA의 농도에 따라 중합속도는 1.38의 반응차수를 가지고 증가하였다. 라디칼중합에 대한 억제물인 DPPH를 첨가하면 억제기간이 생기고 이 억제기간은 DPPH의 농도에 따라 증가하였다. 이 중합계에 대한 겉보기 총 활성화 에너지는 13.2kcal/moe임을 알았다. MMA($M_1$)과 styrene($M_2$)의 공중합체에 대한 단위체 반응성비는 $r_1$=2.35, $r_2$=0.78이었다. 그리고 이러한 실험결과에서 이 계에 의한 중합개시 메카니즘을 논의하여 디라디칼에 의한 중합이 우세하게 일어난다고 생각되었다.

• Carbon letters
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• 제7권4호
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• pp.266-270
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• 2006

Multi-walled carbon nanotube-poly methyl methacrylate (MWNT/PMMA) nanocomposite has been prepared by in situ polymerization of MMA dispersed with MWNTs. The MWNTs were functionalized by nitric acid and sulfuric acid treatment, and this was confirmed by FTIR spectrometer. The solution mixture of MWNTs and MMA was partially polymerized at $80^{\circ}C$, followed by the addition of AIBN and polymerization at $50^{\circ}C$. The MWNT-PMMA composite was prepared by casting the pre-polymer on the glass plate, and the optical properties have been studied using UV-vis spectrometer. The acid treated MWNTs were well dispersed in MMA with fairly good dispersion stability, while flocculation and sedimentation was observed from raw MWNTs in MMA.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.324-335
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• 2019

Timber from plantation forests has inferior physical and mechanical properties compared to timber from natural forest because it is mostly from fast-growing tree species that are cut at a young age. Filling cell voids with methyl methacrylate (MMA) can improve the wood properties. The purpose of this study was to determine the physical and mechanical properties of MMA-impregnated wood from three fast-growing wood species, namely jabon (Anthocephalus cadamba (Roxb.) Miq.), mangium (Acacia mangium Willd) and pine (Pinus merkusii Jungh. & de Vriese). Wood samples were either immersed in MMA monomer or impregnated with it and then heated to induce the polymerization process. Jabon, which was the lowest density wood, had the highest polymer loading, followed by pine and mangium. The physical and mechanical properties of samples were affected by wood species and the presence of MMA, with higher-density wood having better properties than wood with a lower density. Physical and mechanical properties of MMA wood were enhanced compared to untreated wood. Furthermore, the impregnation process was better than immersion process resulting the physical and mechanical properties. Based on MOR values, the MMA woods were one strength class higher compared to untreated wood with regard to Strength Classification of Indonesian Wood.

• Macromolecular Research
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• 제12권5호
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• pp.519-527
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• 2004

Stable poly(methyl methacrylate-co-divinylbenzene) (poly(MMA-co-DVB)) microspheres were prepared by precipitation polymerization using acetonitrile as the main medium under various polymerization conditions, including modifications of the agitation speed, monomer and initiator concentrations, DVB content in the monomer mixture, and the use of various cosolvents. Gentle agitation was required to obtain smooth spherical particles. The individually stable microspheres were obtained at monomer concentrations of up to 15 vol% in an acetonitrile medium. The number-average diameter increased linearly with respect to increases in the monomer and initiator concentrations. We found, however, that the uniformity of the microspheres was independent of the variation of the polymerization ingredients because nuclei formation was solely influenced by the crosslinking reaction of the monomers. We obtained higher yields for the polymerization at higher concentrations of monomer and initiator. The concentration of DVB in the monomer mixture composition played an important role in determining not only the size of the microspheres but also the yield of the polymerization. In addition, although we employed various cosolvents as the polymerization medium, we found that acetonitrile/2-methoxyethanol was the only system that provided spherical particles without coagulation. This finding indicates that the precipitation polymerization is strongly dependent on the solvent used as the medium.

• 폴리머
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• 제34권1호
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• pp.14-19
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• 2010

여러 원인에 의한 석조문화재의 풍화 손상을 저지할 목적으로 아크릴계 고분자를 이용하는 가압함침 보존 처리방법에서 함침된 고분자와 무기물질인 석재와의 친화성을 높이도록 silane계 아크릴 단량체의 사용을 연구하였다. 기본 단량체인 methyl metacrylate(MMA)에 vinyl trimethoxy silane(VTMS)의 함량을 변화시키고 라디칼 중합으로 MMA-VTMS 공중합체를 얻어 이들 공중합체의 유리전이온도, 평균분자량, 그리고 저장탄성률의 변화를 평가하여 benzoyl peroxide (BPO) 1 wt%, 중합시간 8시간, 그리고 VTMS 5 mol% 혼합의 경우(PMV5)가 최적 혼합비율과 중합조건임을 알 수 있었다. 실제 국내산 화강암과 풍화된 암석의 시편을 함침 보존처리한 후 수분 흡수율, 충격특성, 내산성 및 접착특성 등을 측정한 결과 MMA 단독 사용과 비교하여 PMV5의 경우 모든 특성에 있어서 개선되는 것을 확인하였다.