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Abstract The bromine chain‐end functionality of polystyrene (PSt) prepared by activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) was analyzed using 500 MHz 1 H nuclear magnetic resonance (NMR). Bulk polymerization of styrene (St) was carried out with 50 ppm of copper in the presence of tris2‐ (dimethylamino) ethylamine (Me 6 TREN) ligand and tin (II) 2‐ethylhexanoate Sn (EH) 2 reducing agent at 90 °C. Due to the use of a low concentration of an active Cu/ligand catalyst complex, it was possible to significantly decrease the occurrence of catalyst‐based side reactions (β ‐H elimination). As a result, compared to PSt prepared via normal ATRP, PSt with improved chain‐end functionality was obtained. For example, at 92% monomer conversion in normal ATRP only 48% of chains retained chain‐end functionality, whereas 87% of the chains in an ARGET ATRP still contained halogen functionality. PSt with controlled molecular weight (M ₍, ₍₌ₑ = 11 600 g · mol −1, M ₍, ₓ₇₄₎ₑ. = 9 600 g · mol −1) and narrow molecular weight distribution (M ₖ / M ₍ = 1. 14) was prepared under these conditions. In addition, as a result of decreased frequency of side reactions in ARGET ATRP, PSt with relatively high molecular weight was successfully prepared (M ₍, ₆₂ = 185 000 g · mol −1, M ₖ / M ₍ = 1. 35). magnified image
Jakubowski et al. (Wed,) studied this question.