Homo‐ and Copolymerization of Norbornene and Styrene with Pd‐ and Ni‐Based Novel Bridged Dinuclear Diimine Complexes and MAO

Abstract

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, Tg, 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 1H NMR spectroscopies, wide‐angle X‐ray diffraction (WAXD), and differential scanning calorimetry (DSC) indicated that the copolymers are “true” copolymers. The reactivity ratios were rstyrene = 0.281, rnorbornene = 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.

Metal catalysts for the vinyl/addition polymerization of norbornene

“…The system Pd-16/MAO was used to study the influence of the polymerization conditions on the catalytic activity. When the molar Al/Pd ratio was decreased from 525 to 35, the activity also decreased, but still remained in the area of 10 5 g PNB /mol Pd h. Furthermore, the activity decreased with a decrease of the monomer concentration [147].…”

“…The dinuclear diimine complex Ni-39, activated with MAO, generated polynorbornene with moderate activity in the range of 10 5 g polymer /mol Ni h and was also applied for the copolymerization of norbornene with styrene [147].…”

Synthesis, structure and norbornene polymerization behavior of nickel complexes bearing two β-ketoiminato chelate ligands

“…The vinylic polymerization of norbornene, yielding a 2,3-connected, rotationally strongly constrained vinyl-type polynorbornene, has been considerably attracted because of the polymer having unique physical properties, such as high glass transition temperature, optical transparency, and low birefringence [5,6]. The vinyl-type polybnorbornene can be prepared using metal complexes based on nickel [7][8][9][10][11][12][13][14][15][16], chromium [17], titanium [18][19][20][21][22][23][24], zirconium [25][26][27][28], iron [29], cobalt [30][31][32], and palladium [16,[33][34][35][36][37][38][39][40][41][42] as catalyst. Zirconocenes and cationic palladium complexes are two types of important catalysts for the vinylic polymerization of norbornene.…”

Polymerization of Methyl Methacrylate with Nickel(II) and Palladium(II) Iminopyridyl Mononuclear Bimetallic Complexes

“…Sun and coworkers have reported the MMA polymerizations by neutral Pd and Ni analogs in which the Pd system showed activity almost double of its Ni analog [28]. Similar observation was also reported for the homoand copolymerization of norbornene and styrene with a binuclear Ni and Pd based diimine complexes [29]. It has also been reported that too high and low steric bulk leads to decrease the catalytic activity in MMA polymerization [30].…”