Synthesis of crown ether‐terminated poly(methyl methacrylate) by radical chain transfer polymerization

Mercapto‐16‐crown‐5 was prepared starting from tetraethyleneglycol and 3‐chloro‐2‐chloromethyl‐1‐propene. Radical polymerization of methyl methacrylate was carried out in the presence of mercapto‐16‐crown‐5 as a chain transfer agent to give crown ether‐terminated poly(methyl methacrylate). The end crown group was characterized by IR and 1H‐NMR spectra. Sodium cation was selectively extracted by this crown‐containing polymer. The molecular weight of the obtained polymer had influence upon the ability of extraction of sodium cation.