Prevailingly isotactic poly(propylene) samples were prepared with a homogeneous catalytic system based on a bis(imino)pyridyl Fe(II) derivative and methylaluminoxane. The polymer microstructure is in agreement with Bernoullian statistics of dyad formation, implicating a "chain-end mechanism of steric control. The latter is operative even at polymerization temperatures as high as +50"C. NMR analysis of polymer end groups indicates that chain growth proceeds via 2,l monomer insertion. The last two findings are unprecedented for isotactic-specific polymerization of propene and are reasonably related to each other.
Isotactic-specific polymerization of propene with an iron-based catalyst: polymer end groups and regiochemistry of propagation
PELLECCHIA, Claudio;MAZZEO, Mina;
1998-01-01
Abstract
Prevailingly isotactic poly(propylene) samples were prepared with a homogeneous catalytic system based on a bis(imino)pyridyl Fe(II) derivative and methylaluminoxane. The polymer microstructure is in agreement with Bernoullian statistics of dyad formation, implicating a "chain-end mechanism of steric control. The latter is operative even at polymerization temperatures as high as +50"C. NMR analysis of polymer end groups indicates that chain growth proceeds via 2,l monomer insertion. The last two findings are unprecedented for isotactic-specific polymerization of propene and are reasonably related to each other.File in questo prodotto:
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