Crystallization and melting behavior of amorphous poly(iminosebacoyl iminodecamethylene)

Multiple melting behavior was observed in the differential scanning calorim etry (DSC) scans for the isothermally crystallized poly(iminosebacoyl imino decamethylene) (PA1010) samples. Coexistence of crystal populations with di fferent lamellar thickness in PA1010 was discussed by means of DSC, wide-an gle X-ray diffraction (WAXD), and small-angle X-ray scattering techniques. During crystallization of the polymer, a major lamellar crystal population developed first, which possessed a higher melting temperature. However, a s mall fraction of the polymer formed minor crystal population with thinner l amellae, which was metastable and, upon post-annealing, could grow into mor e stable and thicker lamellae through melting and recrystallization process . Lamellae insertion or stacks would develop during the post-annealing at a lower temperature for the isothermally crystallized samples; thus, multipl e crystal populations with different thickness could be produced. It is the multiple distribution of lamella thickness that gives rise to multiple mel ting behavior of crystalline polymers. (C) 2000 John Wiley & Sons, Inc.