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首页> 外文期刊>Polymers for advanced technologies >Synthesis, characterization and liquid crystal-aligning properties of new poly{3-[4-(n-alkyloxy)phenyloxy]pyromellitimide}s
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Synthesis, characterization and liquid crystal-aligning properties of new poly{3-[4-(n-alkyloxy)phenyloxy]pyromellitimide}s

机译：新型{3- [4-（n-烷氧基）苯氧基]均苯四甲酰亚胺} s的合成，表征及液晶取向性能

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摘要

Four new polypyromellitimides (MC{sub}m-PPIs and MC{sub}m-OPIs, m = 6,8) that are singly substituted with a flexible w-alkyloxy side branch at the pyromellitimide ring were prepared by the two-step polycondensation of 3-[4-(n-alkyloxy)phenyloxy]pyromellitic dianhydrides (MC{sub}m-PMDAs, m = 6, 8) with p-phenylenediamine (PDA) and 4,4'-oxydianiline (ODA), respectively. The dianhydride monomers were synthesized from durene via several reaction steps. Inherent viscosities of the precursor poly(amic acid)s ranged from 0.57 to 1.58 dl/g. After chemical structures of the polyimides had been characterized, their thermal properties, crystalline structures, and liquid crystal (LC) aligning abilities on their rubbed thin films were determined and discussed in comparison to the polypyromellitimides that are doubly substituted at the pyromellitimide ring with the same side branches. For all polymers thermogravimetric analysis (TGA) programs showed a typical two-step degradation behavior with onset temperatures in the 430-455℃ range. In X-ray scattering studies all the samples were found to be amorphous, but the presence of a loosely developed layer structure could be confirmed, in which two main chains gather together to form a double-strand backbone layer and w-alkyl branches fill the space between the layers. On the rubbed surfaces of the polyirnide thin films LCs uniformly aligned parallel to the rubbing direction with the pre-tilt angles 5-7 in MC{sub}m-OPIs and 18-32°in MC{sub}m-PPIs.
机译：通过两步缩聚反应制备了四个新的聚均苯四甲酰亚胺（MC {sub} m-PPI和MC {sub} m-OPI，m = 6,8），它们在均苯四甲酰亚胺基环上被柔性的w-烷氧基侧支取代。分别用对苯二胺（PDA）和4,4'-氧二苯胺（ODA）制备3- [4-（n-烷氧基）苯氧基]均苯四甲酸二酐（MC {sub} m-PMDAs，m = 6、8）。通过几个反应步骤，由杜伦烯合成二酐单体。前体聚（酰胺酸）的固有粘度为0.57至1.58dl / g。在表征了聚酰亚胺的化学结构之后，确定并讨论了它们在摩擦薄膜上的热性能，晶体结构和液晶（LC）对准能力，并与在均苯四甲酰亚胺环上被双苯并四甲酰亚胺双取代的聚均苯四甲酰亚胺进行了比较。侧枝。对于所有聚合物，热重分析（TGA）程序均显示出典型的两步降解行为，起始温度在430-455℃范围内。在X射线散射研究中，发现所有样品都是无定形的，但是可以确认存在松散形成的层结构，其中两个主链聚集在一起形成双链主链层，而w-烷基分支填充了层之间的空间。在聚酰亚胺薄膜的摩擦表面上，LC平行于摩擦方向均匀对齐，MC {sub} m-OPI中的倾斜角为5-7，MC {sub} m-PPI中的倾斜角为18-32°。

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