Acta Chimica Sinica ›› 2007, Vol. 65 ›› Issue (21): 2443-2448. Previous Articles     Next Articles



  1. (1华东理工大学材料科学与工程学院 上海 200237)
    (2中国科学院长春应用化学研究所 长春 130022)
  • 投稿日期:2007-03-12 修回日期:2007-03-28 发布日期:2007-11-14
  • 通讯作者: 袁荞龙

Aqueous Catalytic Polymerization of Ethylene by Neutral Nickel(II) Complexes

ZHAO Chun-Bin1; YUAN Qiao-Long*,1; HUANG Bao-Tong1,2   

  1. (1 School of Materials Science & Engineering, East China University of Science and Technol-ogy, Shanghai 200237)
    (2 Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022)
  • Received:2007-03-12 Revised:2007-03-28 Published:2007-11-14
  • Contact: YUAN Qiao-Long

Aqueous polymerizations of ethylene catalyzed by a series of neutral nickel(II) complexes coordinated with salicylaldimines have been performed in the presence of surfactants, and the lower branched high molecular weight polyethylene was obtained. The results showed that the catalytic activity of the catalysts and the properties of the polyethylene were influenced by the electronic and steric effects of the substituents attached on the benzene ring in the complexes. With increasing the electron withdrawing substituents in the phenoxy ring, the catalytic activity was increased, and the molecular weight of polyethylene decreased. Meanwhile, both of the catalytic activities and the molecular weights of polyethylene were increased with increasing the steric effect of the substituents in aniline. The molecular weights of the polyethylene obtained in an aqueous system were in the range of 104~105. The DSC analysis of the polyethylene indicated that the degrees of crystallinity and the melting points were 50%~70% and 115~137 ℃, respec-tively. The GPC results displayed that the molecular weight distribution of the polyethylenes cocatalyzed by bis(1,5-cyclooctadiene)nickello)[Ni(COD)2] presented bimodal to unimodal with the electronegativity of the groups attached on the phoenxy circle being increased. The variation of the molecular weight and polydispersity of the polyethylenes were further demonstrated by the dynamic rheological researches.

Key words: aqueous catalytic polymerization, ethylene, salicylaldimine, neutral nickel(II) complex