頁籤選單縮合
題 名 | Synthesis, Characterization and Mesomorphic Behavior of Liquid Crystalline Copolysiloxane Polymers: Ⅲ. with an Oligo (Ethylene Oxide) Unit and a Cyano Unit in the Side Chain |
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作 者 | Chang-chien,Guo-ping; | 書刊名 | Journal of Polymer Research |
卷 期 | 5:2 1998.04[民87.04] |
頁 次 | 頁85-93 |
分類號 | 346.84 |
關鍵詞 | Liquid crystalline; Side chain; Copolysiloxane polymers; X-ray diffraction; Differential scanning calorimeter; Bi-layer structures; |
語 文 | 英文(English) |
英文摘要 | The syntheses and characterizations of copolymers (poly[MS3BDBE3)-co- (MCN)]x/y)(where x/y represents the molar ratio of the two structural units on the side chain) were accomplished in this study. Differential scanning calorimeter (DSC) was used to determine the transition temperatures, enthalpy changes and entropy changes of the mesophase phase. The layer spacings (dl) in the mesophases of the homo- and co-polysiloxanes were determined by an X-ray diffractometer equipped with a temperature-controlling Pt hot stage. From DSC thermal data and X-ray diffraction analysis, we found both mixed and double bilayer smectic C mesophases at lower MCN concentrations and a mixed and bilayer smectic A mesophases at higher MCN concentrations. The microstructures of the copolymers poly[MS3BDBE3)-co-(MCN)]x/y are different from those of the copolymers poly[(MS3BDBE1)-co-(MCN)]x/y reported previously. Mesophase and layer spacing of the copolymer are dependent on the MCN concentration in the copolymer. Incorporation of MCN into the copolymer increases the entropy change, which is the result of a loss of positional order contributed by conformational or orientational disorder. |
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