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Ziegler - Natta 와 Metathesis 촉매에 의한 측쇄형 액정폴리아세틸렌 유도체의 합성
오세용,Akagi,Kazuo,Shirakawa,Hideki 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.1
1-[p-(trans-4'-alkylcyclohexyl)phenoxy]alkyne, 5-p-pentylbiphenoxy-1-pentyne과 같은 액 정 moiety를 갖는 새로운 치환아세틸렌을 합성하여, Ziegler-Natta와 metathesis 촉매로 중합하였다. GPC, IR, NMR, UV-Visible 분광학 장치를 사용하여 고분자의 분자향 및 구조를 조사하였다. 특히 Ziegler-Natta 촉매인 Fe(acac)₃-AlEt₃은 중량평균분자량이 2-3×10^6의 고분자량과 입체규칙성이 뛰어난 cis 형 구조의 고분자를 생성하였다. 모든 고분자는 벤젠, 클로로포름, THF와 같은 유기용매에 용해되었다. We have synthesized novel mono-substituted acetylenes with a liquid crystalline moiety such as 1-[p(traps-4'-alkylcyclohexyl)phenoxy]alkynes and 5-p-pentylbiphenoxy-l-pentyne and then polymerized them with Ziegler-Natta and metathesis catalysts. Molecular weights and structure of these polymers were investigated by using GPC, IR, NMR and UV-visible spectroscopic measurements. Especially, Ziegler-Natta catalyst[Fe(acac)₃-AlEt₃] produced an extremely high molecular weight polymer of M_w=2-3×10^6 and cis form polymer with a high stereoregularity. All polymers were soluble in organic solvents such as benzene, chloroform and THF.
측쇄형 액정폴리아세틸렌 유도체의 열안정성 및 액정 성질에 관한 연구
오세용,Akagi,Kazuo,Shirakawa,Hideki 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.2
Ziegler-Natta와 metathesis 촉매를 사용하여 측쇄에 mesogenic moiety로서 cyclohexylphenyl 또는 biphenyl기를 갖는 액정폴리아세틸렌 유도체를 합성하였다. 특히 metathesis 촉매(MoCl_5-Ph₄Sn)로 합성한 고분자는 trans형의 배위를 가지며, Ziegler-Natta 촉매계의 고분자보다 열안전성이 우수하였다. 시차주사열량계와 편광현미경의 측정으로 모든 고분자의 액정 성질을 조사하였다. Alkylcyclohexylphenyl 또는 pentylbiphenyl기를 함유한 고분자는 fan-shaped 구조를 가지는 smectic A 액정상을 나타내었다. 또한 상전이에 따른 엔탈피 변화, cis형에서 trans 구조로의 열 이성화 및 분자량에 관해서 이들 고분자의 분광학적 특성을 분석하였다. We have synthesized liquid crystalline polyacetylene derivatives with a cyclohexyl phenyl or biphenyl group as a mesogenic moiety in the side group by using Ziegler-Natta and metathesis catalysts. Especially, polymers prepared by the metathesis catalyst(MoCl_5-Ph₄Sn) had traps-rich configuration, and their thermal stability was more excellent than polymers prepared by the Ziegler-Natta catalyst. Liquid crystalline properties of all polymers were investigated through measurements of differential scanning calorimetry(DSC) and polarizing microscopy. The polymers consisting of alkyl cyclohexylphenyl or pentylbiphenyl group are found to show a smectic A liquid crystalline phase with a fan-shaped texture. Spectroscopic characteristics of these polymers were also analyzed with respect to molecular weights, thermal isomerization of the cis to traps form and enthalpy changes associated with phase transitions.
Goh, Munju,Park, Jinwoo,Han, Yehdong,Ahn, Sangbum,Akagi, Kazuo The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.48
<P>The chirality transfer of axially chiral binaphthyl derivatives bearing liquid crystal (LC) moieties at the <I>n</I>,<I>n</I>′ positions (<I>n</I> = 3, 4, 6) of the binaphthyl rings to nematic (N) and smectic (S) LCs is investigated. Chiral nematic LCs (N*-LCs) are prepared by adding a small amount of the chiral binaphthyl derivative into host N-LCs composed of cyanobiphenyl mesogen cores. The binaphthyl derivative with phenylcyclohexyl (PCH) type LC moieties at the 4,4′ positions of the binaphthyl ring [<B>D-4,4′</B>] exhibits a low helical twisting power (HTP) of 11 μm<SUP>−1</SUP>. In contrast, those with LC moieties at the 3,3′ and 6,6′ positions of the binaphthyl rings [<B>D-3,3′</B> and <B>D-6,6′</B>] exhibit high HTPs of 153 μm<SUP>−1</SUP> and 154 μm<SUP>−1</SUP>, respectively. Next, the binaphthyl derivatives are added into two types of S-LCs with phenylbenzoate mesogen cores: 4-(4-methylpentyloxy)phenyl-4-(decyloxy)benzoate [<B>PhB1</B>] and 4-(3-methylpentyloxy)phenyl-4-(decyloxy)benzoate [<B>PhB2</B>]. The mixture of the host LC, <B>PhB1</B> or <B>PhB2</B> with the chiral dopant, <B>D-3,3′</B> or <B>D-6,6′</B> shows chiral smectic LCs C (S<SUB>C</SUB>*-LCs). The highly twisted S<SUB>C</SUB>* phases with helical pitches of 1.2–1.4 μm are prepared in <B>PhB1</B> and <B>PhB2</B> by using the chiral dopant of <B>D-6,6′</B>. It is concluded that <B>D-6,6′</B> has a large helical twisting power and is the most favourable atropisomeric chiral inducer for chirality transfer to both N-LCs and S-LCs.</P> <P>Graphic Abstract</P><P>POM images of N* and S<SUB>C</SUB>* phases induced by adding atropisomeric chiral binaphthyl derivatives into N- and S<SUB>C</SUB>-LCs, respectively. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm35282f'> </P>