Zn‐assisted cooperative effect for copolymers made by heterodinuclear Fe−Ni catalyst
Mostafa Khoshsefat, Abbas Dechal, Saeid Ahmadjo, M. M. Mortazavi, Gholamhossein Zohuri, João B. P. Soares
Abstract
Abstract Mononuclear Fe and Ni based catalysts (M 1 and M 2 ) in the form of single and dual catalytic systems were employed in the presence and absence of diethyl zinc (DEZ) for polymerization of ethylene. In addition, corresponding homo‐ (M 3 and M 4 ) and heterodinuclear catalysts (M 7 ) along with the mononuclear analogues (M 5 and M 6 ) were used to explore the effect of adjacency of second metal center on the chain transfer efficiency. DEZ had stronger influence on the behavior of mono‐ and dinuclear Fe‐based structures and corresponding thermal and microstructural properties of the PE samples than Ni complexes. A mechanism was proposed for M 5 as the vinyl‐terminated polymer chains increased in the presence of DEZ. More interestingly, M 7 not only showed a cooperative effect for production of a random copolymer containing short and long chain branches but also at low and high concentration of DEZ, a blocky copolymer was obtained through CCTP and CSP. These results were confirmed by 13 C NMR, DMTA, SSA and CEF.