Polymerization of styrene using novel bispyrazolylimine dinickel (II)/methylaluminoxane catalytic systems

• Published in: Journal of applied polymer science Vol. 122; no. 1; pp. 545 - 550
• Main Authors: Wang, Yuan-yuan, Li, Ben-xia, Zhu, Fang-ming, Gao, Hai-yang, Wu, Qing
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05.10.2011; Wiley; Wiley Subscription Services, Inc
• Subjects: Applied sciences; bispyrazolylimine dinickel (II); Catalysis; Catalysts; complexes; coordination mechanism; Exact sciences and technology; Materials science; methylaluminoxane; Molecular weight distribution; Nickel; Organic polymers; Physicochemistry of polymers; Polymerization; Polymers; Polystyrene resins; Preparation, kinetics, thermodynamics, mechanism and catalysts; styrene polymerization; Styrenes; Ligand effect; styrene polymerization; Complex catalyst polymerization; Complex catalyst; Experimental study; bispyrazolylimine dinickel (II); methylaluminoxane; Dinuclear complex; Pyrazole derivatives; Reaction mechanism; Styrene polymer; Bromo complex; Aluminium Organic compounds; Catalyst activity; Atactic polymer; coordination mechanism; Nickel II Complexes; complexes
• ISSN: 0021-8995; 1097-4628; 1097-4628
• DOI: 10.1002/app.34122

The polymerization of styrene with a series of bispyrazolylimine dinickel (II) complexes of bis‐2‐(C3HN2(R1)2‐3,5)(C(R2) = N(C6H3(CH3)2‐2,6)Ni2Br4 (complex 1: R1 = CH3, R2 = Ph; complex 2: R1 = CH3, R2 = 2,4,6‐trimethylphenyl; complex 3: R1 = R2 = Ph; complex 4: R1 = Ph, R2 = 2,4,6‐trimethylphenyl) in the presence of methylaluminoxane (MAO) was studied. The influences of polymerization parameters such as polymerization temperature, Al/Ni molar ratio, reaction time, and catalyst concentration on catalytic activity and molecular weight of the polystyrene were investigated in detail. The influence of the bulkiness of the substituents on polymerization activity was also studied. All of the four catalytic systems exhibited high activity (up to 10.50 × 105 gPS/(mol Ni h)) for styrene polymerization and provide polystyrene with moderate to low molecular weights (Mw = 4.76 × 104–0.71 × 104 g/mol) and narrower molecular weight distributions about 2. The obtained polystyrene was characterized by means of FTIR, 1H‐NMR, and 13C‐NMR techniques. The results indicated that the polystyrene was atactic polymer. The analysis of the end groups of polystyrene indicated that styrene polymerization with bispyrazolylimine dinickel complexes/MAO catalytic systems proceeded through a coordination mechanism. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.