STRUCTURE DEVELOPMENT IN THE UNIAXIAL-DRAWING PROCESS OF POLY(ETHYLENE NAPHTHALATE)

Amorphous films of poly(ethylene naphthalene-2,6-dicarboxylate) were d rawn isothermally up to desired draw ratios at 130, 140, 150 and 160 d egrees C mainly to study structure formation during uniaxial drawing b y wide-angle X-ray diffraction (WAXD). The results were analysed in co mparison with stress-strain curves in order to find the draw ratio ass ociated with the onset of crystallization at the above-mentioned tempe ratures. To obtain further detailed information, birefringence and den sity were measured for the films drawn at 150 degrees C to elucidate t he relationship between the degree of chain orientation and the crysta llinity. A series of results was discussed in relation to previously r eported interesting phenomena of the time-resolved two-dimensional WAX D patterns recorded using the imaging plate system (Polymer 1995, 36, 291). Copyright (C) 1996 Elsevier Science Ltd.