AlCl3 x OPh2-Co-initiated cationic polymerization of anethole: Facile access to high molecular weight polymers under mild conditions

The AlCl3 x OPh2-co-initiated cationic polymerization of anethole, a biomass-derived vinyl monomer, in toluene and alpha,alpha,alpha-triflurotoluene as less toxic solvents as compared to traditionally used chlorinated ones has been reported. The investigations of the effect of temperature, solvent nature, proton trap addition as well as co-initiator concentration allowed to establish optimal conditions for the synthesis of relatively high molecular weight polymers. Polyanethole with Mn up to 21,000 g mol(-1) with moderate polydispersity (D <= 3.5) were obtained in toluene at -20 degrees C in the presence of 2,6-lutidine as a proton trap at low co-initiator concentration (13 mM). It was shown that all synthesized polymers contain high molecular weight fraction, which is generated due to the chain transfer to monomer via its alkylation followed by the copolymerization of obtained macromonomers with anethole. The content of high molecular weight fraction can be successfully reduced down to < 7% by the increase the reaction temperature and a use of less polar solvent (toluene). The synthesized polyanetholes showed high glass transition temperature values (T-g > 237 degrees C), high thermal stability (T-d5 > 383.5 degrees C) and high Young modulus (E = 3.1 +/- 0.6 GPa) that makes the polymer perspective for the application as high-performance materials.

Automated summary

The AlCl3 x OPh2-co-initiated cationic polymerization of anethole, a biomass-derived vinyl monomer, was successfully conducted in less toxic solvents compared to traditionally used chlorinated solvents. The synthesis of high molecular weight polyanethole with moderate polydispersity was achieved by controlling temperature, solvent nature, proton trap addition, and co-initiator concentration. The synthesized polymers contained a high molecular weight fraction generated through chain transfer to monomer and subsequent copolymerization with anethole. The content of the high molecular weight fraction could be reduced by increasing reaction temperature and using less polar solvents. The synthesized polyanetholes exhibited high glass transition temperature, thermal stability, and Young modulus, making them promising for high-performance materials.