Cover Picture: Macromol. Chem. Phys. 17/2005

Abstract

Cover: Gas-phase assisted surface polymerization (GASP) of methyl methacrylate (MMA) with a simple initiating system, Fe(0)/abromophenylacetate (MBPA), produced high molecular weight PMMA on Fe(0)-metal surfaces, suggesting a physically controlled propagation process on the surfaces. Further details can be found in the Full Paper by

Gas‐phase‐assisted surface polymerization of methyl methacrylate with Fe(0)/TsCl initiator system

“…Bulk polymerization of MMA with simple initiator system: Fe(0)/organic halides In a previous report, 16 it was found that a simple initiator system Fe(0)/methyl a-bromophenylacetate (MBP) was able to initiate the radical polymerization of MMA on iron powder surfaces in a gas phase, suggesting a physically controlled polymerization behavior; that is, it was shown that the molecular weight of the obtained polymer increased with increase in its yield. However, the number-average molecular weight (M n ) of the obtained polymer was lower than 7400 even after 24 h at 608C, suggesting a slow propagation process.…”

“…Results are listed in Table II. During the GASP of MMA, the surface color of Fe(0) powder changed from gray to dark red, which indicated the formation of oxidized species, Fe(II) and/or Fe(III) chlorides on the Fe(0) surface as previously reported when using the Fe(0)/MBP system. 16 A large amount of deposit was found on the Fe(0) powder surface with a simple system Fe(0)/TsCl without ligand (run 2-1). Interestingly, this system gave a high molecular weight polymer of 36,000 M n , showing a high initiator efficiency of 0.0221 in comparison with the result in the liquid phase (Table I).…”

“…Previously, we found that a simple system zero-valent iron (Fe(0))/methyl a-bromophenylacetate could initiate a physically controlled polymerization of MMA and St on metal surfaces without any oxidized Fe(II)/Fe(III) species and ligand. 16 However, only low molecular weight polymers, of less than 7400 in M n, were obtained by the initiator system. These results interested us because if the molecular weight could be increased then the GASP process could have potential applications in many fields.…”

Iron(III) chloride/R‐Cl/tributylphosphine for metal‐catalyzed living radical polymerization: A unique system with a higher oxidation state iron complex

“…[1][2][3][4][5][6][7] One of the most widely employed and efficient living radical polymerizations is the one based on a metal catalyst that generates the growing radical species from the carbon-halogen polymer terminal via the reversible redox reaction of the metal center. The various effective central metals, such as Ru(II), 8 Cu(I), [9][10][11] Ni(II), 12,13 Fe(II), [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] and so forth, give one electron upon the formation of the radical species from the dormant carbon-halogen covalent bond and thus should be basically in a low oxidation state.…”

“…[14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Alternatively, iron(III) halides were employed in conjunction with similar ligands in the presence of a radical initiator like 2,2 0 -azobisisobutyronitrile (AIBN), in which Fe(III) was reduced to Fe(II) via the reaction with the initiating radical species (RÁ) along with the formation of an alkyl halide (RAX).…”