End-capping of polystyrene by aliphatic primary amine by derivatization of precursor hydroxyl end group

A new and very efficient route for the synthesis of aliphatic primary amine terminated polystyrene (PS) is reported. In contrast to most known methods, only traditional commercially available reagents are used. PS is synthesized by anionic polymerization with a lithium counter ion and the living chains are end-capped by a hydroxyl group upon addition of ethylene oxide followed by protonation. The -hydroxyl end group is tosylated and the tosylate is then reacted with sodium azide. The azide terminal group is finally reduced into primary amine. The different steps of functionalization have been fully characterized by SEC, ToF-SIMS, FTIR, and 1H NMR. The amine content (= 98%) has been determined by acid-base titration with perchloric acid. It clearly shows the efficiency of the synthetic method reported in this article although it is a multistep method.