Influence of the surface chemistry of activated carbons on the ATRP catalysis of methyl methacrylate polymerization

A parent activated carbon (C-0) was subjected to four different treatments: (i) heat treatment at 1273 K in Ar (C-1); (ii) heat treatment at 473 K in air (C-2); (iii) oxidation with H2O2 (C-3) and, (iv) oxidation with HNO3 (C-4). These materials were evaluated as supports of CuBr–[1,1,4,7,10,10-hexamethyltriethylenetetramine] (CuIBr–HMTETA), a catalyst for the Atom Transfer Radical Polymerization (ATRP) of methyl methacrylate (MMA) using methyl-α-bromophenylacetate (MBP) as radical initiator. The supported catalysts showed an adequate control of polymerization, evidenced by polydispersity indexes (PDI) falling in the range 1.13–1.55. The best performance was achieved when activated carbon was treated with nitric acid (C-4) and with air at 473 K (C-2). Some copper leaching was always detected. The catalysts were reused and an adequate polymerization control was obtained in subsequent runs.

Graphical abstractAtom Transfer Radical Polymerization (ATRP) of methyl methacrylate (MMA) using a CuBr–[1,1,4,7,10,10-hexamethyltriethylenetetramine] (CuIBr/HMTETA) catalyst (Cat) supported on activated carbon.Figure optionsDownload full-size imageDownload high-quality image (140 K)Download as PowerPoint slideHighlights► Carbon is a suitable support of CuBr/HMTETA for ATRP polymerization of MMA. ► Carboxylic groups on the surface provide high polymerization control. ► Lack of surface functionalization is detrimental for the catalytic behavior.