Living Character of Polymer Chains Prepared via Nitroxide-Mediated Controlled Free-Radical Polymerization of Methyl Methacrylate in the Presence of a Small Amount of Styrene at Low Temperature

Abstract

This article follows a previous study (Macromolecules 2005, 38, 5485) demonstrating that the nitroxide SG1-mediated polymerization of methyl methacrylate can be achieved at 90 °C with high conversion and high quality of control by introducing a small amount of styrene. In this work, the resulting polymer was characterized and the presence of SG1-based alkoxyamine at the polymer chain-end was identified, supporting the livingness of the macromolecules. In particular, it was shown that the alkoxyamine end group was connected to a single styrene terminal unit and that the methyl methacrylate penultimate unit had a strong effect on the temperature of dissociation. Consequently, the copolymerization of methyl methacrylate with a low molar proportion of styrene could be performed at temperatures below 90 °C. The polymer was also used as an efficient macroinitiator in the polymerization of styrene and n-butyl acrylate, to form methyl methacrylate-based block copolymers.

Diasteromeric Effect on the Homolysis of the C–ON Bond in Alkoxyamines: A DFT Investigation of 1,3-Diphenylbutyl-TEMPO

“…However, no ambiguous discussions were provided on the origin of this effect. At a first glance, although this led to apparently contradictory measurements [10,15,16], such small differences in k d may look unimportant, but nevertheless, we have recently shown that the fate of NMP [11,12,17] and the occurrence of side-reactions [18] depends on such small differences.…”

“…During the last decade, the effect of the penultimate unit on the C-ON bond was poorly investigated, and seemingly contradictory results were published concerning polystyryl-TEMPO alkoxyamines. Until recently, it has been shown [10] that the penultimate unit may exert a dramatic effect on the C-ON bond homolysis and, consequently, on the fate of NMP [11,12]. Georges and colleagues [13] measured the C-ON bond homolysis in the diastereoisomers of styryl dyads of TEMPO-based alkoxyamines 7 ( Figure 1).…”

Thermo-responsive, UV-active poly(phenyl acrylate)-b-poly(diethyl acrylamide) block copolymers

“…This is due to the added SG1 pushing the equilibrium between dormant and active chains towards the dormant chains, resulting in slower polymerizations [32,33]. A similar effect of additional free SG1 nitroxide was observed for the polymerizations done at 110°C.…”

Joining Efforts of Nitroxide-Mediated Polymerization (NMP) and Cobalt-Mediated Radical Polymerization (CMRP) for the Preparation of Novel ABC Triblock Copolymers

“…In all the cases, polystyrene standards ranging from 580 to 225×10 4 g/mol were used for calibration. 1 The purified copolymer was then analyzed by 1 …”