Structure and morphology of semicrystalline polymers
Résumé
The different levels of organization of matter in semicrystalline polymers are discussed. The crystalline state is described both from a crystallographic (unit cell and motif) and from a macromolecular point of view (packing of molecules with planar or helical conformation). The partial crystallinity of polymers as well as the anisotropy of polymer crystals are taken into account. The basic morphologies in synthetic polymers are also described: the crystalline lamellae obtained by crystallization from dilute solutions as well as from the melt, and the spherulites, which are complex arrays of crystalline lamellae separated by amorphous layers. The morphologies can be deeply modified by processing conditions: flow, temperature gradients, surfaces.