• 폴리머
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• 제26권3호
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• pp.287-292
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• 2002

산소분위기에서 전자선을 조사하여 과산화물을 생성시킨 폴리프로필렌에 benzoyl peroxide (BPO)를 개시제로 사용하여 비닐계 단량체인 스티렌과 glycidyl methacrylate (GMA)를 기상 그라프트 반응시켰다. 합성체의 그라프트율은 반응온도가 증가함에 따라 증가하는 경향을 나타내었고, 단량체가 스티렌의 경우 $70^{\circ}C$에서 최대였으며, GMA의 경우 반응온도 $80^{\circ}C$에서 최대로 나타났다. 반응시간에 따른 최대 그라프트율은 스티렌이 GMA보다 높게 나타났다 단량체 내 증류수의 조성에 따른 그라프트율은 사용되어지는 단량체의 비등점에 영향을 받는 것으로 나타났다.

• 한국응용과학기술학회지
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• 제16권2호
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• pp.171-177
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• 1999

The objectives of this study is to investigate the optimum reaction conditions and to identify the product formula in the synthesis of a silicone/acrylic resin that curing in moisture at room temperature. By the addition polymerization of monomers, n-butyl acrylate, methyl methacrylate, n-butyl methacrylate, and 3-methacryloxypropyltrimethoxysilane. a quarter polymer was obtained. Among various initiators investigated in this study, 2.2'-azobisisobutyronitrille was found to be the most suitable initiator. The optimum reaction conditions found in this study are 70 wt% of initial solvent amount, 120 minutes of dropping time, 3 times of initiator addition, $82{\sim}105^{\circ}C$ of reaction temperature, and 8 hrs of reaction time. Also, number average molecular weight of $11700{\sim}33100$ and molecular weight distribution of $1.81{\sim}3.44$ were obtained.

• Macromolecular Research
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• 제10권2호
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• pp.108-114
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• 2002

Poly(butylene succinate) (PBS) prepolymers were prepared by the condensation polymerization of 1,4-butanediol (1,4-BD) and succinic atid (SCA) in the presence of titanium (VI) isoproxide(TPI) catalyst. The PBS prepolymers reacted with 1,4-BD or SCA to obtain hydroxyl or carboxylic acid group terminated PBS. High molecular weight linear or branched PBS was synthesized by a coupling reaction between hydroxyl and carboxylic acid group terminated PBS, or by a branching reaction between carboxylic acid group terminated PBS and glycerol as a branching agent. The weight average molecular weight of the prepared linear or branched PBS was in the range of 100,000-220,000. Both melting point and thermal stability of the high molecular weight linear and branched PBSs were somewhat higher than those of general PBS. From a tensile behavior by Instron test, modulus, tensile strength and elongation at break improved with increase in the molecular weight of the prepared PBS through the coupling or the branching reaction. In particular, the high molecular weight linear PBS had about 2.5 times higher value in modulus than the branched one.

• Macromolecular Research
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• 제15권6호
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• pp.541-546
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• 2007

The combination of atom transfer radical polymerization (ATRP) and click chemistry was employed for the efficient preparation of well-defined block copolymers. Bromo terminated poly(methyl acrylate) (pMA-Br) was prepared by an ATRP initiator, ethyl-2-bromoisobutyrate (EBiB). Subsequently, the bromine chain end of pMA-Br was converted to an azide group by simple nucleophilic substitution reaction. ${\alpha}-Alkyn-{\omega}-bromo-functionalized$ polystyrene was also synthesized by ATRP using the alkyn-functionalized initiator, propargyl-2-bromoisobutyrate (PgBiB). In both cases, the conversion was limited to a low level to ensure a high degree of chain end functionality. Then the coupling reaction between the azide end group in $pMA-N_3$ and alkyn-functionalized PgBiB-pSt was performed by Cu(I)catalysis. This coupling reaction was monitored by gel permeation chromatography (GPC). The synthesized block copolymer was characterized by FT-IR, $^1H-NMR$ spectroscopy and $^1H-^1H$ COSY correlation spectroscopy.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2584-2592
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• 2011

Nickel nanoparticle-poly(N-vinyl-2-pyrrolidone)/$TiO_2-ZrO_2$ composite (Ni-PVP/$TiO_2-ZrO_2$) was prepared by in situ polymerization method. The physical and chemical properties of Ni-PVP/$TiO_2-ZrO_2$ were investigated by XRD, FT-IR, BET, TGA, SEM and TEM techniques. The catalytic performance of this novel heterogeneous catalyst was determined for the Suzuki-Miyaura cross-coupling reaction between aryl halides and phenylboronic acid in the presence of methanol-water mixture as solvent. The effects of reaction temperature, the amount of catalyst, amount of support, solvent, and amount of metal for the synthesis of Ni-PVP/$TiO_2-ZrO_2$, were investigated as well as recyclability of the heterogeneous composite. The catalyst used for this synthetically useful transformation showed considerable level of reusability besides very good activity.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2618-2626
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• 2010

In this paper poly (4-methyl vinylpyridinium hydroxide)/SBA-15 composite was prepared as a highly efficient heterogeneous basic catalyst by in situ polymerization method for the first time. It was characterized by XRD, FT-IR, BET, TGA, SEM and back titration using NaOH. This catalyst exhibited the excellent catalytic activities for the Knoevenagel condensation of various aldehydes with ethyl cyanoacetate. Over this catalyst, ${\alpha},{\beta}$-unsaturated carbonyl compounds were obtained in the reasonable yield at $95^{\circ}C$ in 10 - 30 min in $H_2O$ as a solvent with a 100% selectivity to the condensation products. Catalyst could be easily recycled after the reaction and it could be reused without the significant loss of activity/selectivity performance. No by-product formation, high yields, short reaction times, mild reaction conditions and operational simplicity with reusability of the catalyst were the salient features of the present synthetic protocol. Presence of $H_2O$ as a solvent was also recognized as a "green method".

• 대한화학회지
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• 제6권1호
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• pp.88-93
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• 1962

The telomerization of vinyl acetate with carbon tetrachloride, chloroform and monochlorobenzene were investigated with respect to the synthesis of those telomers, properties and molecular weights of the formed telomers, and reaction mechanisms. Vinyl acetate reacted with carbon tetrachloride and chloroform to form telomers at 70-90$^{\circ}C$ and 60-70$^{\circ}C$, respectively and it formed polymer with monochlorobenzene. As a chain transfer agent, carbon tetrachloride was more effective than chloroform. In the telomerization of vinyl acetate and carbon tetrachloride: 1) The average molecular weight of the telomer decreased as the mole ratio of carbon tetrachloride to vinyl acetate increased. The optimum conditions for the highest yield of the telomer were as follows: Mole ratio of carbon tetrachloride to vinyl acetate : 2.5 Reaction time : 20 hours. 2) As the reaction proceeded, the refractive index and average molecular weight of the telomer increased rapidly in the first 10 hours but the increase was slow through the next 10 hours, so that, the average recurring number(n) of taxogen in the final product reached an almost definite value, i.e., 3. The telomer formed in the telomerization of vinyl acetate with carbon tetrachloride and chloroform turned to brown color in the air due to decomposition or polymerization. The suggested telomerization mechanism was supported by the hexachloroethane detected in the course of reaction.

• 한국식품과학회지
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• 제31권5호
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• pp.1262-1267
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• 1999

겔 형성이 어려운 유채단백질의 겔화를 위하여 미생물성 TGase의 촉매작용에 의하여 최적 겔화 반응조건을 겔강도(g)와 겔변형(mm)을 조사하여 검토하였다. 또한 형성된 겔의 고분자화를 SDS-PAGE 및 GL교차결합 함량 측정에 의하여 확인하였다. 단백질-TGase반응에서 효소 첨가량은 $45^{\circ}C$에서 60분 동안 반응 시 단백질농도가 10%에서 효소가 1 : 40([E] : [S])의 비로 첨가되었을 때 겔강도와 변형 값이 가장 높았다. 또한 이 조건에서 기질단백질 농도가 $4{\sim}l2%$로 증가함에 따라 겔강도는 비례적으로 증가함을 보였으나 겔의 변형을 고려할 때 10% 농도가 유채단백질 겔 제조에 적당한 농도로 조사되었다. 최적 활성을 나타내는 반응온도는 $45^{\circ}C$로 관찰되었고, 반응시간은 90분이면 적당한 것으로 조사되었다. 겔강도와 변형은 다른 pH와 비교할 때 pH 7에서 상당히 높은 값을 보여 pH 7이 최적조건이었다. SDS-PAGE분석에서 효소반응 에 따라 유채단백질의 본래 밴드들이 소별되거나 희미해지면서 고분자 밴드들이 형성되고 있음을 보여주었다. 또만 HPLC 분석 결과 GL교차결합 함량이 반응시간에 따라 $0\;{\mu}mol/g$에서 최고 $7.14\;{\mu}mol/g$ gel(반응 90분)까지 증가되고 있어 유채단백질의 겔화가 TGase에 의해 이루어지고 있다는 것을 확인할 수 있었다.

• 공업화학
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• 제5권3호
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• pp.524-536
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• 1994

생체적합성이 좋은 천연고분자인 chitosan에 수용성의 비닐계 단량체인 polyethyleneglycol monomethacrylate series를 그라프트중합시켜 그 반응조건과 물성을 검토하였다. 그라프트중합은 ethylene oxide 부가몰수에 따라 PE-90, PE-200, PE-350의 세 가지 단량체에 ceric ammonium nitrate(CAN)를 개시제로 사용하였으며, 중합에서 개시제의 농도, 단량체의 농도, 반응온도, 반응시간이 총전환율, 그라프트율, 그라프트효율에 미치는 영향을 조사하여 최적조건을 규명하였다. 반응은 개시제농도 $4{\sim}5{\times}10^{-3}M$, 단량체농도 0.5~0.6M, 반응시간 2~3시간, 반응온도 $40^{\circ}C$에서 최고의 그라프트율과 총전환율을 나타냈다. 합성한 공중합체의 열적 성질, 용해성 및 점성도를 검토한 결과 고농도의 개시제를 사용하면 그라프트 중합체는 chitosan의 특성을 급격히 감소시켰다. 고유점성도의 경우, chitosan-g-PE-90이 2.81dl/g, chitosan-g-PE-200이 3.01dl/g, chitosan-g-PE-350이 4.93d1/g으로 증가하는 경향이 나타났다. 공중합체를 막으로 성형하여 그라프트율과 polyethyleneglycol monomethacrylates의 ethylene oxide 부가몰수에 따른 공중합체의 기계적 물성과 함수율을 측정하였다. 가교화 공중합체막은 150분 이내에 함수율이 평형에 이르렀다. 공중합체의 물성은 그라프트율과 ethylene oxide 부가몰수의 영향을 받았으며 chitosan의 기계적 물성과 함수율이 공중합체에서 증가되었음을 확인하였으며 그라프트율이 증가함에 따라 vitamin $B_{12}$의 투과량도 증가하였다.

• 공업화학
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• 제27권5호
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• pp.537-542
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• 2016

본 연구에서는 불균일계 불소화 개질 공정을 이용하여 열분해잔사유(PFO)로부터 메조페이스 피치를 제조하였다. 이 공정은 다양한 온도의 직접 불소화 공정과 $390^{\circ}C$의 열처리 공정을 통하여 진행하였다. 제조된 피치는 연화점, 원소분석, 푸리에 변환 적외선 분광 분석, 고분해능 X-ray 회절 분석 그리고 편광 현미경 분석을 실시하였다. 제조된 피치의 탄소 함량은 직접 불소화 공정의 반응 온도 증가에 따라 함께 상승하였으며, 그 산소, 질소 그리고 황 성분은 완전하게 제거되었다. 불소화 온도가 증가함에 따라서, 메조페이스 소구체의 생성, 성장, 합체, 정렬이 관찰되었다. 탄소 육각망면의 층간간격이 감소하였고 결정자 크기가 증가하였다. 또한, 지방족 화합물의 축 중합으로 인한 방향족 화합물의 함량 증가가 관찰되었다. 이러한 결과는 반응 온도의 증가에 따라 증가된 불소 라디칼의 반응성에 기인한다. 불소화 반응은 열분해잔사유가 라디칼 반응에 의한 중합반응의 촉진으로, 방향족 화합물의 생성을 돕는 것으로 판단된다.