| Abstract: | Recent advances in transition metal catalyzed olefin polymerization and melt processing stimulate the production of new polymers derived from old monomers. Modern polyolefin processes do not require polymer purification and give excellent control of molecular and supermolecular polyolefin architectures. Progress in catalyst design and preparation of tailor-made homo-and copolymers is highlighted for isotactic, syndiotactic, atactic and stereo-block polypropylene (PP), novel 1-olefin copolymers, and ethylene copolymers with polar monomers, e.g., CO and acrylics. Today polyethylene short-and long-chain-branching is controlled either by uniform ethylene copolymerization with 1-olefins using single-site” metallocene catalysts, or by migratory polyinsertion of ethylene, respectively. Stiff cycloaliphatic polymers expand the frontiers of polyolefins into engineering applications. New families of polyethylenes and EPM with pendent polypropylene chains are obtained via copolymerization of PP macromonomers or polymer-analoguous coupling of functionalized PP during melt processing. |
