Magnetic orientation of poly(ethylene terephthalate)

A new finding is reported on the magnetic orientation of poly(ethylene terephthalate) (PET) in the magnetic field of 6 T. The orientation is observed to start during the induction period of isothermal crystallization from melt. This observation is in accord with the observation that we made for the magnetic orientation of other two crystalline polymers, i.e. poly(ethylene-2,6-naphthalate) and isotactic polystyrene, reported in our previous papers. The results obtained in this study is in support of the assumption that some ordered structure formed during the induction period is responsible for the magnetic orientation though the detail of this ordered structure is still open to discussion. Crystallites formed after a prolonged crystallization time exhibited the orientation with a*-axis roughly aligned perpendicular to the magnetic field. This alignment of a*-axis is explained in terms of the diamagnetic susceptibility of the aromatic ring in the crystal of PET. (C) 1999 Elsevier Science Ltd. All rights reserved.