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Homo‐ and Copolymerization of Norbornene and Styrene with Pd‐ and Ni‐Based Novel Bridged Dinuclear Diimine Complexes and MAO
Author(s) -
Mi Xia,
Ma Zhi,
Wang Leyong,
Ke Yucai,
Hu Youliang
Publication year - 2003
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200390057
Subject(s) - diimine , norbornene , copolymer , polymer chemistry , methylaluminoxane , styrene , palladium , polymerization , chemistry , glass transition , nickel , materials science , catalysis , polymer , organic chemistry , metallocene
Novel bridged dinuclear diimine nickel and palladium complexes catalyzed the vinyl addition polymerization of norbornene at a single active site with high activity. The latter exhibited higher activity than the former. Smaller substituents around the imido group in the ligand were more favorable for increasing the activity than bulkier ones. The polynorbornenes were all noncrystalline but had short‐range order and their glass transition temperature, T g , ranged from 270 to 400 °C. Furthermore, the random copolymerization of norbornene and styrene was catalyzed by the bridged dinuclear diimine nickel complex with MAO (methylaluminoxane). Gel permeation chromatography (GPC), FTIR and 1 H NMR spectroscopies, wide‐angle X‐ray diffraction (WAXD), and differential scanning calorimetry (DSC) indicated that the copolymers are “true” copolymers. The reactivity ratios were r styrene = 0.281, r norbornene = 18.7. The packing density, thermostability and the glass transition temperatures of copolymers are increased relative to polystyrene. The solubility and processability of the copolymers are improved relative to polynorbornene.The structures of bridged dinuclear diimine nickel and palladium complexes.