Poly(p-phenylene)s with Mesogenic Side Groups: A Potential Class of NII Side Chain Liquid Crystalline Polymers?
Poly(p-phenylene)s with Mesogenic Side Groups: A Potential Class of NII Side Chain Liquid Crystalline Polymers?
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DOI：
10.1021/ma9900129
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发表时间：
1999-03
期刊：
影响因子：
5.5
通讯作者：
V. Percec;A. D. Asandei;D. Hill;D. Crawford
中科院分区：
文献类型：
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作者：
V. Percec;A. D. Asandei;D. Hill;D. Crawford
描述了一系列在烷基间隔基中含有 n = 2 至 12 亚甲基的 n-[(4-氰基-4’-联苯基)氧基]烷基-2,5-二氯苯甲酸酯单体的合成和表征，以及它们的 Ni(0) 催化聚合，以生产含有介晶侧基的聚(对亚苯基) (PPP)。所得侧链液晶聚合物（SCLCP）具有刚性棒状介晶主链和刚性棒状介晶侧基。所有聚合物仅表现出宽的对映异构向列相并且没有侧链结晶。与具有柔性或半柔性主链的聚合物相比，这些 SCLCP 的各向同性温度随着聚合度 (DP) 的增加而急剧增加。因此，在平台 DP 之上，它们的各向同性温度高于具有柔性或半柔性主链的聚合物，尽管它表现出对间隔基长度的经典奇偶依赖性。这些不寻常的趋势可能表明向列相的导演......
The synthesis and characterization of a series of n-[(4-cyano-4‘-biphenylyl)oxy]alkyl-2,5-dichlorobenzoate monomers containing from n = 2 to 12 methylenic groups in the alkyl spacer and their Ni(0)-catalyzed polymerization to produce poly(p-phenylene)s (PPP) containing mesogenic side groups are described. The resulting side chain liquid crystalline polymers (SCLCPs) have both a rigid rodlike mesogenic backbone and rigid rodlike mesogenic side groups. All polymers display only a broad enantiotropic nematic phase and no side-chain crystallization. The isotropization temperature of these SCLCPs exhibits a steeper increase with the degree of polymerization (DP) than that observed for polymers with flexible or semiflexible backbones. Therefore, above plateau DPs their isotropization temperature is higher than that of polymers with flexible or semiflexible backbones, although it displays a classic odd−even dependence on the spacer length. These unusual trends may indicate that the director of the nematic phase ...