高等学校化学学报 ›› 1991, Vol. 12 ›› Issue (12): 1681.

• 研究论文 • 上一篇    下一篇

异相Ziegler-Natta催化剂的活性中心多分散性(Ⅰ)--钛催化体系聚合物分子量分布的研究

范志强, 封麟先, 杨士林   

  1. 浙江大学化学系, 杭州, 310027
  • 收稿日期:1991-03-28 出版日期:1991-12-24 发布日期:1991-12-24
  • 通讯作者: 封麟先
  • 基金资助:

    国家自然科学基金

Plurality of Active Centers on Heterogeneous Ziegler-Natta Catalysts(Ⅰ)--Studies on the Molecular-Weight Distribution of Polymer Synthesized by Titanium Catalysts

Fan Zhi-qiang, Feng Lin-xian, Yang Shi-lin   

  1. Department of Chemistry, Zhe Jiang University, Hangzhou, 310027
  • Received:1991-03-28 Online:1991-12-24 Published:1991-12-24

摘要: 对TiCl3及TiCl4/MgCl2-Al(C2H5)3(或Al(i-C4H9)3、Al(C2H5)2Cl)催化体系合成的聚辛烯的分子量分布用SchulzeFlory"最可几分布"函数作拟合处理,将各种聚合条件下的实测分布分成了3~5个"最可几分布"的叠加,催化剂结构及聚合条件对这些"最可几分布"峰的位置、大小的影响较有规律,表明每个峰对应于一种活性中心。还测定了聚辛烯各级分的活性中心浓度。对各活性中心的差异作了分析。

关键词: Ziegler-Natta催化剂, 活性中心, 多分散性, 分子量分布

Abstract: The molecular-weight distribution (MWD) graphs of polyoctene-1 synthesized by TiCl3or TiCl4/MgCl2with A1(C2H5)3, A1G-C4H9)3or A1(C2H5)2Cl were accurately fitted with 3-5 Schulz-Flory "the most probable" distributions of different position and area, and the position and area of the theoretical distributions change regularly with the catalyst and polymerization conditions, showing that each of the "the most probable" peaks corresponds to a certain kind of active center, and the broad MWD (Mw/qn=3-12) of the studied polymer is the results of 3-5 kinds of active centers. The plurality of active centers was also evidenced by measuring thenumber of active centers in the polymer fractions of different molecular-weight. The characteristics of different active centers as well as the polymerization mechanism are discussed based on the results of MWD fitting.

Key words: Ziegler-Natta catalyst, Active center, Plurality, Molecular-weight distribution

TrendMD: