The dual melting behaviour of a rigid aromatic polyimide synthesized from 1,4-bis(4-aminophenoxy-4'- benzoyl)benzene and oxydiphthalic dianhydride was analysed. Film samples were synthesized through a stepwise imidization procedure wherein molecular weight control was effected through stoichiometric offset. The films display a glass transition temperature of 217°C and dual endothermic transitions at ca. 334°C and 364°C. Transmission electron microscopy, wide angle X-ray diffraction and small angle X-ray scattering (SAXS) studies, in conjunction with dynamic scanning calorimetry (d.s.c.) analysis, show that the higher melting transition results from the melting of lamellae which were melt recrystallized during heating in the d.s.c.D.s.c, heating rate studies reveal that the rate of transformation from thin to thick lamellae is dependent upon molecular weight, as expected. Synchrotron SAXS analysis confirms that the melt recrystallization process is very rapid for this high glass transition, low molecular weight polymer
Посилання на статтю:
Study of the multiple melting behaviour of the aromatic polyimide LaRC CPI-2 / Don K. Brandom and Garth L. Wilkes // Polymer. – 1994. – Vol 35. – P. 5672-5677.