Mesophase structures in poly(ethylene terephthalate), poly(ethylene naphthalate) and poly(ethylene naphthalate bibenzoate)

Films of poly(ethylene naphthalate) (PEN) and poly(ethylene naphthalate 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 combination of low temperature and high-strain rate encourages mesophase formation, while in PENBB the mesophase was formed under ail conditions where if proved possible to draw the material at all. A molecular modelling 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 Wiley & Sons, Ltd.