• 대한화학회지
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• 제26권4호
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• pp.235-246
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• 1982

본 연구에서는 자유라디칼 메카니즘에 의한 N-acetyl ${\alpha}$-aminoacrylic acid의 단독중합 반응속도와 혼성중합 반응성을 연구하였으며, DMF 용매를 사용하여 $60^{\circ}C$에서 단독중합 시켰을 때의 중합속도 ($R_p$)는 단위체 농도 [M]와 개시제 농도 [I]에 대하여 $R_p$ = $k_p[M]^{0.97}[I]^{0.59}$의 관계를 나타내었다. 또한 이 단위체의 단독중합 총괄 활성화 에너지는 25.2 kcal/mole이었다. N-acetyl ${\alpha}$-aminoacrylic acid를 아크릴산 및 스티렌 단위체와 혼성중합 시켰을 때의 단위체 반응성비는 아래와 같았다. $r_1$(N-acetyl ${\alpha}$-aminoacrylic acid) = 0.49, $r_2$(acrylic acid) = 1.41; $r_1$(N-acetyl ${\alpha}$-aminoacrylic acid) = 0.44, $r_2$(styrene) = 0.91. Alfrey-Price 식을 이용하여 계산한 N-acetyl ${\alpha}$-aminoacrylic acid의 Q와 e값은 두 경우 모두 Q=0.51, e=0.16이었다. 단독중합체 및 혼성중합체들의 열적성질을 DTA 및 TGA법으로 분석하여 비교하여 보았다.

• 공업화학
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• 제28권1호
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• pp.73-79
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• 2017

이축압출기(twin screw extruder)를 이용하여 $190^{\circ}C$에서 말레인산 무수물(maleic anhydride, MAH)과 스티렌 모노머(styrene monomer, SM)의 함량을 변화시켜가며 MAH와 SM이 그래프트된 폴리프로필렌(PP-g-MAH-SM) 공중합체를 제조하였다. 제조한 PP-g-MAH-SM 공중합체의 그래프트율은 비수용성 역적정을 통하여 측정하였으며, 동일한 MAH 함량에서 SM이 사용된 경우 높은 그래프트율을 나타내었다. 그래프트율에 따른 PP-g-MAH-SM/케나프섬유(kenaf fiber, KF) 복합체를 $200^{\circ}C$에서 제조하였고, KF의 함량은 20 wt%로 고정시켰다. 복합체에 대한 열중량분석기(TGA)의 분해온도에 따르면, MAH 만 적용된 PP-g-MAH 보다 MAH와 SM이 함께 적용된 PP-g-MAH-SM 복합체의 열안정성이 다소 우세하였다. 복합체의 기계적 강도 또한 MAH와 SM이 함께 적용된 경우에 개선정도가 우수하였다. 계면접착정도는 파단면의 SEM과 접촉각으로 확인하였다.

• 폴리머
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• 제36권2호
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• pp.216-222
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• 2012

콘크리트 제조 시 잉여수의 지연 흡수를 위하여 가교된 crosslinked poly(styrene-$alt$-maleic anhydride)(PSMA)가 core이고, PSMA가 shell인 마이크로캡슐 흡수제를 침전중합법으로 제조하였다. Shell의 두께를 조절하기 위하여 (core 단량체의 질량)/(shell 단량체의 질량) 비가 1/1, 1/2 및 1/3이 되도록 하여 cPSMA-PSMA를 중합하였다. FTIR spectrometer를 사용하여 시멘트 포화 수용액 내에서 PSMA가 가수 분해 반응이 일어남을 확인하였다. TEM 분석으로 core/shell 단량체 비가 1/2(cPSMA #3)일 때 마이크로캡슐 구조를 잘 형성하는 것을 관찰하였고, 1/1(cPSMA #2)과 1/3(cPSMA #4)은 불완전한 마이크로캡슐 구조임을 관찰하였다. 시멘트 포화 수용액에서 cPSMA #3의 팽윤비는 초기 20분까지 증가한 후 2시간까지는 감소하였으며, 그 후 24시간까지는 다시 증가하였다. 제조된 cPSMA #3을 시멘트 페이스트에 첨가한 후 시간에 따른 점도 측정 결과 1시간까지는 거의 변화가 없었지만, 그 후 급격한 점도 증가가 일어났다. Core로만 구성된 cPSMA #1을 0.5 wt% 첨가한 시멘트 모르타르의 압축강도는 무첨가 시멘트 모르타르에 비해 약 5% 높게 나타났으며, cPSMA #3을 첨가한 모르타르는 약 7% 증가로 가장 높게 나타났다.

• 한국산업보건학회지
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• 제18권4호
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• pp.310-317
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• 2008

The objective of the survey is to define and judge exposure profiles semi-qualitative data in high risk processes using styrene. The survey was conducted on 98 factories out of 229 factories based on data from periodic working environment monitoring for styrene. Styrene is widely utilized as a raw material for PS and co-polymers such as ABS, SAN, SBR, SBL, unsaturated polyester resins(UPR) and others. An approximate breakdown of styrene's markets in Korea is PS 30%, expandable PS 17%, ABS 33%, SAN 5%, SBL 4%, SBR 3%, UPR 1% and other 7%. Although UPR accounts for 1% of total amount of styrene, workers dealing with it are exposed to very high concentrations up to 64 ppm. Especially styrene is widely used in the laminating process of fiberglass reinforced plastics(FRP) manufacturing industry. The Applications using styrene are largely classified into two sections which are applied to styrene monomer(SM) and UPR. SM is utilized for a raw material of resins, surfactant and adhesive. UPR is employed for FRP and non-FRP. For SM control targets are mixing colors and packing in the gelcoat resins manufacturing industry(MI), for UPR control targets out of works using UPR are 1) laminating in the MI of plastics, automobile parts and boats, 2) mixing and packing in the SMC/BMC MI, 3) molding and cutting in the other specific plastics MI, 4) mixing and coating in artificial marble product MI, 5) dipping in the electric motors & transformers MI, 6) molding in the button MI, 7) painting in the musical instrument MI. Findings from the study have given the information for the high risk processes and working practices so that occupational health professionals could focus on targeted workplaces to prevent occupational diseases. It is also useful to develop a control strategies and specific controls for high risk processes and facilities using styrene.

• Bulletin of the Korean Chemical Society
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• 제17권3호
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• pp.245-253
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• 1996

A topological theory has been introduced to explain and evaluate the fractional volumes of system materials, the change of the weight and concentration of monomer molecules, molecular weight distribution, and interaction functions of polymer-polymer and polymer-oligomer, etc. for dispersion polymerization. The previous theory of Lu et al. has offered only an incomplete simulation model for dispersion polymer systems, whereas our present one gives a general theoretical model applicable to all the polymerization systems. The theory of Lu et al. considered only the physical property term caused by interaction between matters of low molecular weight (i.e., diluent, monomer, and oligomer) and polymer particles without dealing with physical properties caused by the structure of polymer networks in polymer particles, while our theory deals with all physical effect possible, caused by the displacement of not only entangled points but also junction points in polymer particles. The theoretically predictive values show good agreement with the experimental data for dispersion polymerization systems.

• Korea-Australia Rheology Journal
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• 제13권2호
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• pp.61-65
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• 2001

Thermoplastic nanocomposites based on the copolymers of polypropylene (PP)-polystyrene (PS) and organically modified montmorillonite (org-MMT) were produced by using power ultrasonic wave in an intensive mixer. Owing to the unique action of the ultrasonic wave, free radicals of styrene monomers and macroradicals of PP were generated, by which copolymers of PP and PS were formed. Another important aspect of using ultrasonic wave during the mixing process was to enhance nano-scale dispersion of org-MMT by destructing the agglomerates of org-MMT in the polymer matrix. Optimum conditions for the in-situ copolymerization and melt intercalation were studied with various concentrations of styrene monomer, sonication time and different kinds of clay. It was found that a novel attempt carried out in this study yielded further improvement in the mechanical performance of the nanocomposites compared to those produced by the conventional melt mixing process.

• 폴리머
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• 제25권5호
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• pp.754-758
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• 2001

Vesicle을 단량체가 중합 반응을 할 수 있는 장소로 사용하기 위하여, vesicle 내의 소수성부분에 단량체와 가교제를 집어넣었다. 즉 dimethyldioctadecylammonium bromide를 증류수 속에서 초음파 분산을 하여 vesicle을 만든 후, 여기에 styrene과 divinylbenzene을 첨가한 다음 AIBN으로 중합시켰다. 형성된 고분자는 남겨두고 vesicle을 형성하였던 계면활성제들을 모두 에탄올로 추출해서 제거하여 순수 고분자로 이루어진 구형의 구조물을 얻었다. 그리고 methyl methacrylate와 ethylene glycol dimethacrylate를 이용해서도 고분자로 이루어진 구형의 구조물을 합성하였다.

• 한국응용과학기술학회지
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• 제28권1호
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• pp.10-14
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• 2011

Emulsion polymerization was carried out using RMA like MMA, EMA, BMA and Styrene(St.) as monomer for core-shell latex preparation. It was synthesized at $80^{\circ}C$ in the presence of anionic surfactant SLS. FT-IR, TGA and DSC analysis are used to confirm synthesized core-shell emulsion latexes and to investigate the thermal characteristics of them. From analysis of TGA and DSC, the differences of the decomposition rate and the activation energy are not so large. It considers that the pendent group is not affect of the thermal characteristics and stability on core-shell latexes, which is synthesized with RMA and Styrene.

• 조명전기설비학회논문지
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• 제25권12호
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• pp.48-53
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• 2011

Polymer thin films were prepared by capacitively coupled plasma polymerization process for application of gate insulator. The polymer thin films revealed to form polymer layers with original properties of the monomer. Among the plasma polymer thin films, the styrene polymer having large number of phenyl sites revealed higher dielectric constant of k=3.7 than that of conventional polymer. The plasma polymerized styrene thin film revealed no hysteresis characteristics and low leakage current density of $1{\times}10^{-8}[Acm^{-2}]$ at field strength of $1[MVcm^{-1}]$, which measured by I-V and C-V measurements using MIM and MIS devices.

• Macromolecular Research
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• 제11권2호
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• pp.87-91
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• 2003

Thermal decomposition reactions of polystyrene using a new heating medium were carried out by a batch system at 190-280 $^{\circ}C$ to clarify the manner in which decomposition is initiated. Polystyrene obtained from a commercial source and low molecular weight compounds obtained from the thermal decomposition were analyzed by GC, GPC, IR, $^{13}$ C-NMR and GC-MS. The main chain underwent virtually no change by heat application. Polystyrene underwent decomposition below its molding temperature and the major decomposition products were 2,4,6-triphenyl-1-hexene (trimer), 2,4-diphenyl-1-butene(dimer) and styrene (monomer). Ethylbenzene, propylbenzene, naphthalene, benzaldehyde, biphenyl and 1,3-diphenylpropane were detected as minor products. This paper presents a new method for examining the decomposition of polystyrene at low temperature into volatile low molecular weight compounds.