Abstract
The interactions of a sterically hindered phenol [2,6(t-Bu)(2)-4-Me-C6H2OH] (BHT) with the scavenger MAO (AlR3) and ZnR2 during Hf/Zr-based chain shuttling polymerization in a semi-batch reactor have been investigated. NMR model studies indicated preferential binding of BHT to aluminum under these conditions. Subsequently, reproducible polymerization runs gave rise to copolymers that were thoroughly characterized by HT-SEC, HT-HPLC, DSC, thermal fractionation (SSA), C-13 NMR, density measurements, CRYSTAF and optical microscopy to unravel their complex microstructures. The obtained materials differ from a simple solution blend of materials, separately produced by single catalysts, but also from multi-block copolymers as obtained by DOW's continuous process, although a blocky structure can be rationalized.