Synthesis of Stereoblock Polypropylenes

Rieger has recently reported another class of Ci catalysts (45) for the synthesis of stereoblock polypropylenes. However unlike the polymers formed using 42—44, polymers ranging from flexible plastics (with melting points as high as 134 °C) to thermoplastic elastomers are produced. Similar metallocenes... 

A conceptually different route to the synthesis of stereoblock polypropylenes entails the repeated exchange of growing polymer chains between active species of different stereoselectivity. Two pathways are conceivable ... 

---