A Copper-Based Reverse ATRP Process for the Living Radical Polymerization of 4-Vinylpyridine: Discussion on Optimum Reaction Conditions

Abstract

In this original experiment, reverse atom transfer radical polymerization technique using CuCl₂/hexamethyl tris[2-(dimethylamino)ethyl]amine (Me₆-TREN) as catalyst complex was applied to living radical polymerization of 4-vinylpyridine (4VP) with azobisisobutyronitrile (AIBN) as initiator. N,N-Dimethylformamide was used as solvent to improve the solubility of the reaction system. The polymerization not only showed the best control of molecular weight and its distribution, but also provided a rather rapid reaction rate with the molar ratio of [4VP]:[AIBN]:[CuCl₂]:[Me₆-TREN] = 400:1:2:2. The rate of polymerization increased with increasing the polymerization temperature and the apparent activation energy was calculated to be 51.5 kJ· mol¹. Use of Cl as the halogen in copper halide had many advantages over the use of Br. The resulting poly(4-vinylpyridine) was successfully used as the macroinitiator to proceed the block polymerization of styrene in the presence of CuCl/Me₆-TREN catalyst complex via a conventional ATRP process in DMF.

Keywords:

• living polymerization
• reverse atom transfer radical polymerization
• 4-vinylpyridine

Acknowledgments

The authors are grateful for the financial support by the Natural Science Foundation of Shandong Province (No. Q2006F05), the Applied Project of Educational Bureau of Shandong Province (No. J08LC03).