Phase identification in a series of liquid crystalline TPP polyethers and copolyethers having highly ordered mesophase structures. 7. Phase structures in a series of copolyethers containing odd and even numbers of methylene units of different compositions
文献类型：期刊论文
| 作者 | Zheng RQ ; Chen EQ ; Cheng SZD ; Xie FC ; Yan DH ; He TB ; Percec V ; Chu PW ; Ungar G |
| 刊名 | macromolecules
 |
| 出版日期 | 1999 |
| 卷号 | 32期号:21页码:6981-6988 |
| 关键词 | DISC-LIKE MESOGENS MAIN-CHAIN SMECTIC PHASES BEHAVIOR CLASSIFICATION POLYMERS |
| ISSN号 | 0024-9297 |
| 通讯作者 | cheng szd |
| 中文摘要 | a series of liquid crystalline copolyethers have been synthesized from 1-(4-hydroxy-4'-biphenyl)-2-(4-hydroxyphenyl)propane with 1,7-dibromoheptane and 1,12-dibromododecene [cotpps(7/12)], which represents copolyethers containing both odd and even numbers of methylene units. the molar ratio of odd to even methylene units in this series ranges from 1/9 to 9/1. the cotpps(7/12) exhibit multiple phase transitions during cooling and heating in differential scanning calorimetry experiments. for all these thermal transitions, a small undercooling and superheating dependence is observed upon cooling and heating at different rates. three types of phase behaviors can be classified in cotpps(7/12) on the basis of the structural analyses by wide-angle x-ray diffraction on powder and fiber samples and by electron diffraction experiments in transmission electron microscopy. at room temperature, highly ordered smectic and smectic crystal (sc) phases are identified in cotpps(7/12: 1/9 and 2/8), which is similar to the homopolymer tpp(m = 12). the cotpps(7/12: 3/7, 4/6, and 5/5) possess a hexagonal columnar (phi(h)) phase in which the molecular and columnar axes are parallel to the fiber direction and perpendicular to the hexagonal lateral packing. the cotpps(7/12: 6/4, 7/3, and 8/2) possess a tilted hexagonal columnar (phi(th)) phase with a single tilt angle which increases with the increasing composition of the seven-numbered methylene units. however, in cotpp(7/12: 9/1), a phi(th) phase with multiple tilt angles is found. upon heating, phase structures in most cotpps(7/12) involving the columnar phases enter directly into the nematic (n) phase, while the cotpp(7/12: 1/9) exhibits a highly ordered smectic f (s-f) phase before it reaches the n phase. one exception is found in cotpp(7/12: 2/8), wherein the transformation from the s-f to phi(h) occurs prior to the n phase. combining the copolymer phase behaviors observed with the corresponding homopolymers tpp(n = 7) and tpp(m = 12), a phase diagram describing transition temperatures with respect to the composition can be constructed. |
| 收录类别 | SCI收录期刊论文 |
| 语种 | 英语 |
| WOS记录号 | WOS:000083222700014 |
| 公开日期 | 2010-11-04 |
| 源URL | [http://202.98.16.49/handle/322003/21569]  |
| 专题 | 长春应用化学研究所_长春应用化学研究所知识产出_期刊论文 |
| 推荐引用方式 GB/T 7714 | Zheng RQ,Chen EQ,Cheng SZD,et al. Phase identification in a series of liquid crystalline TPP polyethers and copolyethers having highly ordered mesophase structures. 7. Phase structures in a series of copolyethers containing odd and even numbers of methylene units of different compositions[J]. macromolecules,1999,32(21):6981-6988. |
| APA | Zheng RQ.,Chen EQ.,Cheng SZD.,Xie FC.,Yan DH.,...&Ungar G.(1999).Phase identification in a series of liquid crystalline TPP polyethers and copolyethers having highly ordered mesophase structures. 7. Phase structures in a series of copolyethers containing odd and even numbers of methylene units of different compositions.macromolecules,32(21),6981-6988. |
| MLA | Zheng RQ,et al."Phase identification in a series of liquid crystalline TPP polyethers and copolyethers having highly ordered mesophase structures. 7. Phase structures in a series of copolyethers containing odd and even numbers of methylene units of different compositions".macromolecules 32.21(1999):6981-6988. |
入库方式： OAI收割
来源：长春应用化学研究所
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