• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.263-266
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• 1996

A method to determine an optimal temperature trajectory that guarantees polymer products having controlled molecular weight distribution and desired values of molecular weight is presented. The coordinate transformation method and the optimal control theory are applied to a batch PMMA polymerization system to calculate the optimal temperature trajectory. Coordinate transformation method converts the original fixed-end-point, free-end-time problem to a free-end-point, fixed-end-time problem. The idea is that by making the reactor temperature track the optimal temperature trajectory one may be able to produce polymer products having the prespecified physical property in a minimum time. The on-line control experiments with the PID control algorithm have been conducted to establish the validity of the scheme proposed in this study. The experimental results show that prespecified polymer product could be obtained with tracking the calculated optimal temperature trajectory.

• 한국전기전자재료학회논문지
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• 제18권1호
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• pp.68-74
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• 2005

In this work, polymerization conditions of the gel polymer electrolyte (GPE) were studied to obtain better electrochemical performances in a lithium-ion polymer battery. When the polymerization temperature and time of the GPE were 70$^{\circ}C$ and 70 min, respectively, the lithium polymer battery showed excellent a rate capability and cycleability. The TMPETA (trimethylolpropane ethoxylate triacrylate)/TEGDMA (triethylene glycol dimethacrylate)-based cells prepared under optimized polymerization conditions showed excellent rate capability and low-temperature performances: The discharge capacity of cells at 2 Crate showed 92.1 % against 0.2C rate. The cell at -20 $^{\circ}C$ also delivered 82.4 % of the discharge capacity at room temperature.

• 한국염색가공학회지
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• 제7권1호
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• pp.43-50
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• 1995

The grafting of methacrylonitrile(MAN) onto Kevlar 49 filament surface was carried out by anionic polymerization using sodium methylsulfinylcarbanion formed from sodium hydride and dimethyl sulfoxide(DMSO). The effects of reaction conditions on the grafting percentage(GP) and on the tensile strength of the fiber were investgated. GP marktedly increased with increasing metalation time, and NaH concentration, polymerization temperature and time. The tensile strength of fiber decrased with increasing metalation time, and NaH concentration, polymerization temperature and time. The optimum conditions to increase over 40% of GP with below 10% reduction rate of tensile strength of fiber : NaH concentration ; 30.6 mmol/l/0.5g Kevlar, metalation time : 10min, polymerization tempera- ture : 5$0^{\circ}C$, polymerization time: 20 sec, monomer concentration : 1.12mol/l/0.5g Kevlar.

• Macromolecular Research
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• 제8권4호
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• pp.147-152
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• 2000

The activity of periodic acid as an initiator for the polymerization of acrylamide in aqueous medium was investigated. The rate of polymerization was found to be proportional to the monomer concentration to the 1.5th power in the range of 1.41-5.64 mol/L. The reaction order to the periodic acid concentration was 0.49, which indicated a bimolecular mechanism for the termination reaction in the range of 0.5-4.0$\times$10$\^$-2/ mol/L. Propagation rate increased with raising the temperature according to an Arrhenius expression resulting in the exhibition of an apparent activation energy of 87.8 kJ/mol in the temperature range of 60-80$\^{C}$. The addition of hydroquinone as a radical scavenger stopped the polymerization of acrylamide initiated by periodic acid. These results support that the polymerization proceeds via a radical chain mechanism .

• Bulletin of the Korean Chemical Society
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• 제18권12호
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• pp.1296-1301
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• 1997

Polymerization of terminal alkynes (phenlacetylene and 4-ethynyltoluene) catalyzed by water soluble rhodium (Ⅰ) complex, RhCl(CO)(TPPTS)2 (TPPTS=m-P(C6H4SO3Na)3) (1) selectively produces cis-transoid polymers at room temperature in homogeneous solution of H2O and MeOH as well as in biphasic solutions of H2O and CHCl3. The rate of polymerization is higher in H2O/MeOH than in H2O/CHCl3. The iridium analog, IrCl(CO)(TPPTS)2 (2) shows catalytic activity for the polymerization of phenylacetylene only at elevated temperature to give trans-polymers. The polymerization rate increases significantly when the trimethylamine N-oxide (Me3NO) was added to the reaction mixtures. The electronic absorption spectra of the cis-transoid polymers show three absorption bands whereas the trasn-polymers show only one absorption band. It seems that the electronic absorption bands depend on the configuration of the polymers.

• Carbon letters
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• 제14권1호
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• pp.45-50
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• 2013

Polyacrylonitrile (PAN) copolymers of different molecular weights were synthesized by a suspension polymerization and precipitation polymerization method. The rheology behaviors of the synthesized PAN copolymers were investigated in relation to their molecular weight, solid content and melting temperature. The influence of "historical effects" on the spinning solution of PAN was studied by analyzing the laws of viscosity considering the diversification time and temperature. The viscosity disciplines of each spinning solution conformed well to the rheological universal laws in a comparison of the suspension polymerization product with that of precipitation polymerization. Viscosity changes in the swelling process of dissolution were gentler in the suspension polymerization product; a small amount of water will quickly debase the solution viscosity, and high-speed mixing can greatly shorten the time required by the spinning solution to reach the final viscosity.

• 접착 및 계면
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• 제15권3호
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• pp.93-99
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• 2014

본 Styrene (ST)과 sodium 1-allyloxy-2-hydroxypropane sulfonate (COPS-I)의 무유화 공중합을 다양한 중합조건(ST, COPS-I, KPS, DVB의 농도 및 중합온도)하에서 실시하여, 165~550 nm 입자경 범위의 단분산 라텍스를 제조하였다. 일반적으로 COPS-I와 KPS의 농도, 중합온도, DVB의 농도 등의 변화는 고분자 입자수(입자경), 중합속도, 분자량, 제타전위 등에 밀접한 영향을 미침을 발견하였다. 입자수의 증가는 중합속도와 제타전위를 증가시켰으나 분자량은 감소하였다.

• Restorative Dentistry and Endodontics
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• 제26권2호
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• pp.134-140
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• 2001

The polymerization shrinkage of composite resins is an important drawback although the composites have many advantages-more esthetic and conservative than metallic restoratives etc. The purposes of this research were to develop a new measurement method and to manufacture an instrument that can measure the initial dynamic volumetric shrinkage of composite resins during polymerization. The instrument was basically an electromagnetic balance that constructed with a force transducer using position sensitive photo detector(PSPD) and a negative feedback servo amplifier of proportional-derivative(PD) controller. The volumetric change of composites during polymerization was detected continuously as buoyancy change in distilled water by means of Archimedes's principle. It was converted to continuous electrical voltage signal in real time. The signal was properly conditioned and filtered and then it was stored in computer by a data acquisition(DAQ) board. By using this electronic instrument. the dynamic patterns of the polymerization shrinkage of eight commercial(Z-100, DenFil, AeliteFil, Z-250, P-60, SureFil, Synergy compact, and Tetric ceram) composite resins were measured and compared. The results were as follows. 1. From this project of developing instrument, the ability has been achieved that can acquire and process data of electrical signal transformed from various physical phenomenon by using temperature, displacement. photo. and force transducer. As a consequence, the instrumentation and measurement system used to analyze the physical characteristics of various dental materials in dental research field can be designed, manufactured and implemented in lab. 2. This instrument has some advantages. It was insensible to temperature change and could measure true dynamic volumetric shrinkage in real time without complicated process. It showed accuracy and high precision results with small standard deviation. 3. The polymerization shrinkage of composites was significantly different between brands and ranged from 2.47％ to 3.89％, The order of polymerization shrinkage was as follows, in order of increasing shrinkage, SureFil, P60, Z250, Z100, Synergy compact. DenFil, Tetric ceram, and AeliteFil. 4. The polymerization shrinkage rate per unit time, dVol％/dt, showed that the instrument can provide an indirect research method for polymerization reaction kinetics.

• 폴리머
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• 제24권5호
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• pp.610-620
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• 2000

아세트산비닐(VAc)을 아조비스디메틸발레로니트릴(ADMVN) 및 삼차부틸알코올 (TBA)을 각각 개시제 및 용매로 하여 30, 40 및 5$0^{\circ}C$에서 용액중합하였다. 합성된 폴리아세트산비닐 (PVAc)을 비누화함으로써 고분자량 혼성배열 폴리비닐알코올(PVA)을 제조하였다. 중합조건들이 전환률, 가지화도 및 PVAc와 PVA의 분자량에 미치는 영향을 고찰하였다. TBA에서의 VAc의 중합 속도는 ADMVN 농도의 0.49승에 비례하였고, 이는 이론치 0.5와 잘 일치하였다. 저온에서 개시가 가능한 ADMVN 및 낮은 사슬이동상수를 갖는 TBA를 사용함으로써 고분자량 및 고수율의 PVA가 얻어졌다. PVAc의 평균 중합도는 전환률 약 35%부터 70%의 범위에서 10000~13000이었고, 이를 비누화하여 얻은 PVA의 평균 중합도는 2400~6100이었다. 교대배열 다이애드기 함량은 중합온도를 낮춤에 따라 조금씩 증가하였고, 중합시 TBA의 입체장애 효과 때문에 TBA의 양을 증가시킴에 따라서도 증가하였다.

• 공업화학
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• 제17권1호
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• pp.33-36
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• 2006

광경화 접착제로 많이 사용되는 우레탄-아크릴레이트 올리고머의 광경화 거동을 자체촉매화 반응모델식을 통해 중합온도 및 올리고머의 관능성에 따른 영향을 확인하여 보았다. 중합온도가 증가함에 따라 최대중합속도는 감소하여 중합온도가 경화 거동에 대한 영향인자임을 확인할 수 있었으며, 반응속도상수 k는 온도증가에 따라 거의 일정한 값을 보이나 반응차수 m과 n은 증가하는 경향을 보였는데 이는 가교구조에 의한 반응성 기의 확산제한 및 유동성의 제한으로 인한 것으로 판단되어진다. 온도증가에 따른 중합속도의 감소는 주로 반응차수 n의 증가에 의해 진행되었다.