A solid-state C-13-NMR study of the mesophases of PEIM-9 (poly(4,4 '-phthaloimidobenzoylnonamethylene- oxycarbonyl))

作者：Cheng JL; Chen W; Pardey R; Cheng SZD; Wunderlich B^*

来源：Polymers for Advanced Technologies, 1999, 10(8): 501-512.

DOI：10.1002/(SICI)1099-1581(199908)10:8<501::AID-PAT902>3.0.CO;2-2

• PEIM-9
• transconformations
• annealing
• crystallization

On cooling from the melt, poly(4,4'-phthaloimidobenzoylnonamethyleneoxycarbonyl) (PEIM-9) forms a monotropic, smectic liquid crystal phase (T-i = 369.2 K). The main driving force for this mesophase formation is the attainment of nanophase separation of the mobile nonamethylene spacer from the geometrically rigid but irregular, phthaloimidobenzoyl group, coupled with partial conformational ordering of the CH2 groups (about 20% of the CH2 groups attain trans-conformations). It is shown by nuclear magnetic resonance that PEIM-9 consists at room temperature of two motionally distinguishable components. One is the liquid crystal that remains mobile to its glass transition temperature (T-g approximate to 323 K), the other a more rigid crystal with a large degree of conformational disorder. In this crystal phase (T-m approximate to 415 K) the conformationally disordered nonamethylene spacer has a similar amount of disorder than in the liquid crystal phase and the phthaloimidobenzoyl group is also not fully ordered. Even after long-term annealing, all molecules remain conformationally disordered but T-m increases to about approximate to 437 K.

• 出版日期1999-8