On spherulitic forms in an aromatic polyesteramide

A particular aromatic polyesteramide with flexible spacers has been shown t o crystallize into a variety of spherulitic forms whose birefringence varie s markedly with crystallization temperature. However, a temperature step cr ystallization technique allows the unambiguous recognition of the different forms in spite of the varying birefringence. Though their appearance under optical and electron microscopy is different, all observed crystalline for ms show very similar X-ray diffraction patterns, which suggests that they s hare a common local molecular arrangement. Each form has a characteristic m elting point which is almost invariant with crystallization temperature. Fr om this it is suggested that the various forms comprise chainfolded crystal s containing different integral lengths of the same rather long monomeric u nit. No liquid crystalline phases were observed in this material. (C) 1999 Elsevier Science Ltd. All rights reserved.