Acta Chimica Sinica ›› 2020, Vol. 78 ›› Issue (12): 1418-1425.DOI: 10.6023/A20070336 Previous Articles     Next Articles



彭伟, 戚佩瑶, 董凯旋, 贺爱华   

  1. 山东省烯烃催化与聚合重点实验室 橡塑材料与工程教育部重点实验室 青岛科技大学高分子科学与工程学院 青岛 266042
  • 投稿日期:2020-07-30 发布日期:2020-10-12
  • 通讯作者: 贺爱华,
  • 基金资助:

Oligomerization and Polymerization of Isoprene Catalyzed by Alkylaluminium with Different Structures

Peng Wei, Qi Peiyao, Dong Kaixuan, He Aihua   

  1. Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization, Key Laboratory of Rubber-Plastics (Ministry of Education), School of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
  • Received:2020-07-30 Published:2020-10-12
  • Supported by:
    Project supported by the Major Scientific and Technological Innovation Project of Shandong Province (No. 2019JZZY010352) and Taishan Scholar Program.

Alkylaluminium (AlR3), as co-catalyst component in Ziegler-Natta catalytic system, plays important roles in the alkylation, forming and changing the structure and concentration of active centers through the reduction and reversible adsorption-desorption reactions with the metal compound of the catalyst, acting as chain transfer agent, etc. However, the alkylaluminium itself do have the catalytic effect on the conjugated diene monomers. In this article, alkylaluminium with different structures such as triethylaluminium (AlEt3), triisobutylaluminium (Al(i-Bu)3), diisobutylaluminium hydride (AlH(i-Bu)2), diethylaluminium chloride (AlEt2Cl), ethylaluminium dichloride (AlEtCl2) were used to catalyze isoprene oligomerization and polymerization. The effects of the structure and concentration of alkylaluminiums (n(Al)/n(M)=7×10-5, 35×10-5, 350×10-5, 1050×10-5) on the catalytic behaviors of isoprene were studied. The microstructure (trans-1,4 and cis-1,4), molecular weight and molecular weight distribution of the products were characterized by 1H nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography (GPC) and gas chromatography-mass spectrometry (GC-MS). It was found that alkylaluminium could initiate oligomerization and cationic polymerization of isoprene under the minor incorporation of H2O, which were affected greatly by the structure and concentration of alkylaluminium. Using AlEtCl2 led to the highest catalytic activity and produced products containing more linear polymers with mixed cis-1,4/trans-1,4 structures when n(Al)/n(M)=1050×10-5. The Al(i-Bu)3 and AlH(i-Bu)2 didn't have basically cation initiation ability, which led to isoprene oligomerization. The alkylaluminium with n(Al)/n(M) ≤ 350×10-5 had negligible influence on the isoprene polymerization and oligomerization. And lower or higher alkylaluminium concentration were not beneficial to obtain polyisoprene with high molecular weight. The catalytic mechanism of alkylaluminium on isoprene was discussed, which provided a further understanding on the catalytic behavior of alkylaluminium components in Ziegler-Natta catalyst and the effect of alkylaluminium on polymers.

Key words: alkylaluminium, isoprene, catalysis, oligomerization, polymerization behavior