Surface-Initiated ATRP of HEA from Nanocrystal α-Fe₂O₃ Under Ultrasonic Irradiation

Core/shell poly(-hydroethyl acrylate) (PHEA) encapsulated nanocrystal α-Fe₂O₃ nanospheres (Fe₂O₃@PHEA) were successfully prepared by the surface-initiated atom transfer radical polymerization (SI-ATRP) of -hydroethyl acrylate (HEA), a functional monomer, from the surfaces of the nanocrystal Fe₂O₃ modified with bromo-acetamide groups with the catalysts of 1, 10-phenanthroline and Cu(I)Br under ultrasonic irradiation at room temperature in water. The products, Fe₂O₃@PHEA, were characterized by elemental analysis (EA), FT-IR, XRD, XPS and TEM. The percentage of grafting (PG%) of 38.95% and the conversion of HEA (C%) of 14.29% at room temperature for 6 h with ultrasonic irradiation were higher than the 22.41% and 8.22%, respectively, found for samples prepared by electromagnetic stirring. This demonstrated that the ultrasonic irradiation improves the SI-ATRP of HEA.