Surface-initiated atom transfer radical polymerization of hydroxyethyl acrylate from activated carbon powder with homogenized surface groups

The well-defined poly( hydroxyethyl acrylate) (PHEA) brushes were grafted from the surfaces of the activated carbon (AC) powder with the controlled/"living" radical polymerization technique. First, surface functional groups of the AC powder were homogenized to hydroxyl groups by oxidizing with nitric acid and then reducing with lithium tetrahydroaluminate (LiAlH4) at first. Second, the surface hydroxyl groups were treated with bromoacetylbromide, and the bromoacetyl groups were introduced. And in the third step, the bromoacetyl activated carbon (BrA-AC) powder were used as macro-initiators for the surface-initiated atom transfer radical polymerization (SI-ATRP) of hydroxyethyl acrylate (HEA) in the presence of 1,10-phenanthroline and Cu(I)Br as catalyst in a water system. The graft parameters calculated from the elemental analyses (EA) results, conversion of monemer (C%) and percentage of grafting (PG%) were 5.74% and 28.7%, respectively, after polymerizing for 5 h. The graft polymerizations exhibited the characteristics of a controlled/"living" polymerization, and no homopolymer was found in the proposed polymerizing process. The preparation procedure of the poly( hydroxyethyl acrylate) grafted activated carbon (PHEA-AC) powder was also investigated by X-ray photoelectron spectroscopy (XPS). The PHEA-AC powder is expected to be used as selective adsorbents because of their abundant homogenized surface hydroxyl groups.