Samarium(III)-based AGET ATRP of Acrylonitrile Using Ascorbic Acid as Reducing Agent

Abstract

Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) initiated by ethyl 2-bromoisobutyrate (EBiB) was approached for the first time in the absence of oxygen and in the presence of air, using a novel catalyst system based on SmBr₃·6H₂O/isophthalic acid complexes and using ascorbic acid (VC) as a reducing agent. Both the polymerization in the absence of oxygen and in the presence of air proceeded in a well-controlled manner as evidenced by kinetic studies. Compared with the polymerization in the absence of oxygen, the polymerization in the presence of air provided rather slow reaction rate and showed better control of molecular weight and its distribution under the same experimental conditions. The polymerization apparent activation energies in the absence of oxygen and in the presence of air were calculated to be 47.1 and 51.3 kJ·mol⁻¹, respectively. A slow polymerization rate and a broad polydispersity index were observed using anisole and toluene instead of DMF as solvent. Polyacrylonitrile obtained was successfully used as a macroinitiator to proceed the chain extension polymerization of styrene via AGET ATRP in the presence of air.

Keywords:

• Atom transfer radical polymerization
• AGET ATRP
• acrylonitrile

Acknowledgments

The authors are grateful for the financial support by the National Natural Scientific Foundation of China (Nos. 20904018, 51073075), the Natural Science Foundation of Shandong Province (Nos. ZR2009FM075, ZR2010BQ007), the Youth Science Foundation of Shandong Province (No. BS2009CL010), the Program for Science and Technology Development of Shandong Province (No. 2009GG10003012), and the Program for Science and Technology Development of Yantai city (No. 2008308).