Application of a new unimolecular initiator in the synthesis of (α,ω) ketone functionalized polystyrene in nitroxide mediated polymerization

摘要

The ketone functionalized N-alkoxyamine, a derivative of 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl (4-oxo-TEMPO) was synthesized and applied as an initiator in the nitroxide mediated polymerization of styrene in bulk at 120°C. In the presence of the prepared initiator: 1-phenyl-1-(4-oxo-2,2,6,6-tetramethylpiperidinoxy)propanone polymers with well-defined molecular weight were obtained. By contrast, when an accelerator such as acetic anhydride (10%) was added to the system, lower control of polymerization was observed. Additionally, the functionality of polymers was evaluated on the basis of a quantitative investigation of UV-visible spectra of 2,4-dinitrophenylhydrazone formed from the polymers and the synthesized initiator. The UV-vis spectra of the hydrazone derivatives obtained from polymers by means of 2,4-dinitrophenylhydrazone made it possible to confirm that the polymers prepared in the presence of the ketone functionalized N-alkoxyamine retain the ketone functionality on the polymer chain. The functionality for the obtained polymers exceeded 1 significantly. The obtained (α, ω) telechelic polymers are of great importance in the synthesis of new biohybrid materials such as bioconjugates with proteins or peptides as well as new polymer nanostructures.