• Bulletin of the Korean Chemical Society
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• 제27권4호
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• pp.475-476
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• 2006

• 공업화학
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• 제27권3호
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• pp.313-318
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• 2016

본 연구에서는 무정형 실리카의 세공 내를 아미노실란인 N-[(3-trimethoxysilyl)propyl]ethylenediamine (2NS)를 이용하여 표면 기능화한 후 표면 기능화된 실리카에 후전이 금속 촉매인 $(DME)NiBr_2$와 $PdCl_2$(COD)를 담지하여 노보넨 중합을 실시하였다. 중합 온도와 중합 시간, Al/Ni 몰비, 조촉매 종류를 변화시켜 중합 특성에 미치는 영향을 조사하였다. 담지되지 않은 촉매($(DME)NiBr_2$, $PdCl_2$(COD))로 노보넨 중합을 수행하였을 경우 중합반응은 일어나지 않았다. 그러나 조촉매로 MAO를 이용하여 중합한 경우 $SiO_2$/2NS/Ni 촉매는 중합 온도가 증가할수록 활성은 증가하였고 폴리노보넨(polynorbornene, PNB)의 분자량은 급격하게 감소하였다. $SiO_2$/2NS/Pd 촉매는 온도가 증가할수록 활성과 PNB의 분자량 모두 감소하는 경향을 보였다. $SiO_2$/2NS/Ni 촉매는 $SiO_2$/2NS/Pd 촉매보다 높은 온도에서 안정함을 확인하였다. 또한 두 촉매 모두 중합 시간이 길어질수록 노보넨의 전환율은 증가하였다. Al/Ni 몰비가 1000 : 1일 때 가장 높은 활성(15.3 kg-PNB/(${\mu}mol-Ni^*hr$))을 보이는 반면 가장 낮은 분자량($M_n$ = 124,000 g/mol)의 PNB를 합성하였다. 또한 조촉매로 Borate/TEAL을 이용하여 중합한 경우 $SiO_2$/2NS/Ni 촉매는 중합 온도가 증가할수록 활성과 분자량이 모두 감소하였다.

• Bulletin of the Korean Chemical Society
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• 제27권7호
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• pp.1031-1037
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• 2006

New nickel complexes containing novel tetradentate ligands, 4,5-substituted-1,2-bis(pyridine-2-carboxamide)-benzene ligands but lacking alkyl or halide ligands in the coordination sphere have been prepared. They were activated with MMAO (modified methylaluminoxane) to be proven as efficient catalysts for the polymerization of norbornene. Both electron-donating and -withdrawing substituents on the benzene ring and polar solvents enhance the catalytic activity for olefin polymerization. Improvement in thermal stability of the complexes was observed. Some of these complexes were crystallographically determined to have square planar geometry. A plausible mechanism involving dissociation of ligands is proposed.

• 폴리머
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• 제39권3호
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• pp.487-492
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• 2015

Palladium(II) 촉매를 이용한 norobornene carboxylic acid estsers의 중합 시 단량체의 알킬 작용기의 종류, endo/exo 비율이 촉매의 활성도 및 중합 특성에 미치는 영향을 조사하였다. Norbornene esters 단량체는 5-norborene-2-carboxylic acid와 다양한 알코올을 반응시켜 합성하였다. 중합 촉매로는 di-$\mu$-chloro-bis(-methoxybicyclo[2,2,1]-hept-2-ene)palladium(II)(DCBMP)를 합성하여 사용하였고, 짝음이온으로 실버 헥사플루오로안티모네이트($AgSbF_6$)를 이용하였다. 고분자의 분석을 위해 젤 투과 크로마토그래피(gel permeation chromatography, GPC), 열 중량 분석법(thermogravimetric analysis, TGA), 시차주사 열량측정법(differential scanning calorimetry, DSC), 화학구조 분석을 위해 $^1H$ NMR spectroscopy를 이용하였다. 분자량 분석 결과 모든 작용기의 경우 endo-이성체의 비율이 exo-이성체의 비율보다 높을 경우 촉매의 구조적 방해로 인하여 반응성이 감소됨을 보였다. 또한 단량체와 촉매의 비율이 중합 거동에 미치는 영향을 조사하기 위해 단량체와 촉매의 몰비율을 100:1, 200:1, 300:1로 변화시켜 실험을 진행하였으며, 이 때 exo-norbornene carboxylic acid octyl ester의 경우 300:1 촉매비에서 필름형성이 가능한 높은 분자량($M_n=27500g/mol$)의 고분자를 합성할 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2720-2724
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• 2013

Polynorbornenes prepared by vinyl addition pathway are known to have some desirable characteristics for wider application but they have some critical drawbacks such as brittleness, poor solubility and adhesion. In order to improve these drawbacks, extensive research for the successful homo- and copolymerization of polar functionalized norbornene with olefin has been carried out. Even though considerable advance has been achieved in the polymerization of polar functionalized monomers, successful catalytic systems for the homopolymerization of polar functionalized norbornene are rare. In this study, a novel successful catalytic system for the polymerization of polar functionalized norborene is proposed. This system employs Pd ${\beta}$-diketiminate/borate cocatalyst in water/organic mixed solvents and it is unique due to introduction of water as a component of solvents. Polymers obtained in this study show high Mw with narrow PDI. Effects of several reaction parameters to the polymer activity and properties are investigated and optimal catalytic system are proposed.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1884-1890
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• 2011

A series of Ni(II) and Pd(II) complexes bearing N4-type tetradentate ligands, [Ni($X^1X^2$-6-$Me_2bpb$) 1] and [Pd($X^1X^2$-6-$Me_2bpb$) 2]; 6-$Me_2bpb$ = N,N'-(o-phenylene)bis(6-methylpyridine-2-carboxamidate), $X^1$ = Cl, H, or $CH_3$, $X^2$ = $NO_2$, Cl, F, H, $CH_3$, or $OCH_3$) were designed, synthesized, and characterized to investigate electronic and steric effects of ligand on the norbornene polymerization catalysts. Using modified methylaluminoxanes as an activator, the complexes exhibited high catalytic activities for the polymerization of norbornene and the nickel complexes exhibited better catalytic activity the palladium complexes. Ni complex 1a with $NO_2$ group on the benzene ring showed the highest catalytic activity of $4.9{\times}10^6$ g of PNBEs/$mol_{Ni}{\cdot}h$ and molecular weight of $15.28{\times}10^5$ g/mol with PDI < 2.30. Complexes with electron-withdrawing groups are more thermally stable (> 100 $^{\circ}C$), and tend to afford higher polymerization productivities than the ones having electron-donating groups. Amorphous polynorbornenes were obtained with good solubility in halogenated aromatic solvents. A vinyl addition mechanism has been proposed for the catalytic polymerization.

• Bulletin of the Korean Chemical Society
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• 제30권3호
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• pp.636-646
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• 2009

A series of the noble palladium complexes containing $\beta$-ketoiminate ligands with internal bases, [Pd(${\eta}^3$-allyl)($\beta$- ketoiminate)], [Pd(Me)($PPh_3$)($\beta$-ketoiminate)] and [Pd(Me)($\beta$-ketoiminate)], have been successfully prepared. Crystallographically determined structures showed that these complexes are distorted square planar and pendant bases of the $\beta$-ketoiminate ligands fail to coordinate to the metal in the first two classes of complexes while bases do coordinate in the 3rd class complexes. These complexes are active towards norbornene polymerization on activation with $H(OEt_2)_2BAr^'_4$ (Ar' = 3,5-bistrifluoromethylphenyl) and modified methylalumioxane (MMAO). MMAO is more efficient for the activation for polymerization. Generally, the polymerization activity increases with the following order; [Pd(allyl)($\beta$-ketoiminate)] < [Pd(Me)($PPh_3$)($\beta$-ketoiminate)] < [Pd(Me)($\beta$-ketoiminate)].

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.3074-3080
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• 2011

We synthesized three novel poly(norbornene bisimide)s by ring opening metathesis polymerization (ROMP) and subsequent hydrogenation. Their thermal, mechanical and optical properties were investigated with TGA, DMA, UV-Vis spectrometer, and optical reflectometer. The new polymers showed high glass transition temperatures over $260^{\circ}C$ and good thermal stability with 5% wt-loss temperature higher than $390^{\circ}C$. When solvent casted, they yielded optically transparent and dimensionally stable films with a relatively low coefficient of thermal expansion of about 50 ppm $K^{-1}$. Therefore, the bisimide moieties substantially enhanced thermal and dimensional stabilities, as compared with normal ROMP-prepared polynorbornene films. Though the water uptake was increased to 0.6 wt-%, this water uptake is still considerably lower than that for polyethersulfones (1.4 wt-%) or polyimides (2.0 wt-%). Hence, the new poly(norbornene bisimide)s may become attractive candidates for flexible substrates of optoelectronic devices such as displays and photovoltaic solar cells.

• 폴리머
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• 제28권3호
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• pp.245-252
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• 2004

5-헥실-2-노보넨 (HNB)과 5-메틸에스터-2-노보넨 (MES-NB)을 양이온 ${\eta}^3$-알릴 팔라듐 촉매인 [(${\eta}^3$-allyl) palladium(tricyclohexylphosphine) trifluoroacetate]와 리튬계 조촉매 [lithium tetrakis(pentafluorophenyl( borate${\cdor}$2.5etherate]를 사용하여 비닐 부가형의 폴리노보넨 공중합체를 합성하였다. 에스터기를 과량 함유한 폴리노보넨을 제조하기 위한 최적 중합 조건을 조사하기 위하여 여러가지 중합조건에 따른 분자량변화와 수율의 변화를 알아보았다. 팔라듐 촉매의 함량이 많을수록 수득율은 증가하는 한편, 분자량은 감소하였으며, 리튬조촉매의 함량은 많을수록 분자량과 수득율이 동시에 증가하였다. 사슬이동체를 이용하여 분자량을 조절할 수 있었고, 사슬이동제의 길이가 긴 1-데센과 1-옥텐이 1-헥센보다 분자량을 더 감소시키는 역할을 하였다. 한편 사슬이동제의 양은 수율에 큰 영향을 미치지 않았다. HNB/MES-NB(투입비 40/60 mol%)의 공종합체의 $^1$H-NMR 과 GPC 분석으로부터, 실제 에스터 함유량으 약 25mol%인 고분자량 (M$_{w}$ : 270,000)의 폴리노보넨 공중합체가 얻어짐을 알 수 있었다.

• Macromolecular Research
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• 제14권4호
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• pp.424-429
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• 2006

The synthesis of a series of poly(POSS-NBE-b-MTD) copolymers was successfully accomplished, taking advantage of sequential, ring-opening, metathesis block copolymerization using $RuCl_2(=CHPh)(PCy_3)_2$ catalyst. By using cyclopentyl-POSS-norbornene (POSS-NBE) monomer as the first block in the block copolymer, living poly(POSS-NBE) with controlled molecular weight and narrow molecular weight distribution was produced. Then, poly(POSS-NBE-b-MTD) copolymers were successfully prepared, in which sequential monomer addition of methyltetracyclododecene (MTD) to the living poly(POSS-NBE) chain ends was utilized to achieve quantitative crossover efficiency. Characterization by $^1H$ NMR spectroscopy and GPC confirmed the high definition and structural integrity of the poly(PO$S-NBE-b-MTD) copolymers. Thermal properties-and morphologies of the POSS-containing block copolymer nanocomposites were also investigated by using thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and wide-angle X-ray scattering (WAXS).