Structure and morphology of crystalline block copolymers prepared by living olefin polymerization

We investigate the structure, the morphology and mechanical properties of crystalline-crystalline and crystalline-amorphous di-block copolymers synthesized by using living, stereoselective polymerization catalysts. Cystalline-crystalline block copolymers (BCP) are formed by polyethylene (PE) block linked to isotactic polypropylene (iPP) or syndiotactic polypropylene (sPP) blocks while crystalline-amorphous samples are formed by PE or sPP block linked to an amorphous rubbery ethylene-co-propylene (EP) segment. A detailed structural characterization has been performed for samples crystallized in the bulk, thin films and stretched fibers and stress-induced phase transformations have been also analyzed. Thin films of BCPs have been epitaxially crystallized onto crystals of organic substrates to achieve a control over the crystallization of both blocks and to obtain ordered nanostructures where the two blocks are organized in separated alternating lamellar domains guided by the orientation of the crystalline lamellae.