Polymerization of 2-alkyl-2-oxazoline in the presence of thiocarbonylthio derivatives: Unveiling a new polymerization mechanism pathway

(5cm×7.5cm) The graphic abstract is optional. It should be a representative of your entire work and not be a duplicate of a graphic already used in the manuscript. Color structures, graphical images, photographs, or reaction schemes are typically good choices, which may be chosen as cover picture. • Poly(2-alkyl-2-oxazoline) functionalization by thiocarbonylthio containing derivatives. • Oxazoline polymerization in the presence of thiocarbonylthio containing derivatives. • Block copolymers. Synthesize of poly(2-methyl-2-oxazoline)s in the presence of thiocarbonylthio compound (TCT) was investigated. Demonstration of the reaction of TCT with oxazolinium growing chains was first assessed, using various thiocarbonylthio containing functions. Then polymerization of 2-alkyl-2-oxazoline monomers in the presence of TCT and a small amount of cationogen polymerization initiator was carried out. Demonstration of the involvement of TCT in the polymerization was undertaken by first studying the relationship between TCT concentration and the molar mass of the formed polymer. The presence of TCT strongly reduced the molar mass of the polymers compared to the polymerizations carried out with initiator only. The polymer structures were characterized by 1 H, 13 C NMR, COSY, HSQC NMR, and DOSY NMR and the chain ends assessments were achieved by MALDI-ToF. The presence of polymers with chemical structures recalling some intermediates observed in cationic RAFT polymerization was evidenced suggesting further investigations. Kinetic studies were performed to confirm the constant growing species concentration overall the polymerization time. 2-methyl-2-oxazoline was fully consumed and TCT nearly completely after 8d 16 h, whereas the subsequent addition of monomer feeds led to a progressive increase in the molar mass of the resulting polymers. A reversible degenerative transfer reaction was then suggested.