MESOPHASE STRUCTURES IN POLY(ETHYLENE-TEREPHTHALATE), POLY(ETHYLENE NAPHTHALATE) AND POLY(ETHYLENE NAPHTHALATE BIBENZOATE)

Films of poly(ethylene naphthalate) (PEN) and poly(ethylene naphthalat e bibenzoate) (PENBB) have been drawn under a variety of conditions of temperature and strain rate to determine the conditions under which a nematic-like mesophase structure can be produced. In PEN the combinat ion of low temperature and high-strain rate encourages mesophase forma tion, while in PENBB the mesophase was formed under ail conditions whe re if proved possible to draw the material at all. A molecular modelli ng study of the mesophase in PEN and in poly(ethylene terephthalate) ( PET) offers possible structures for the mesophase and showed that the mesophase structure could be stable once formed. (C) 1997 by John Wile y & Sons, Ltd.