Mn(salen)Cl was applied as a low‐cost catalyst for the formation of alkoxyamines from nitroxides and substituted styrenes. These “unimolecular initiators” for nitroxide‐mediated radical polymerization (NMRP) were synthesized using 2,2,6,6‐tetramethyl‐1‐piperidine‐1‐oxyl and 2,2,5‐trimethyl‐4‐phenyl‐3‐azahexane‐3‐oxyl. Functionalized alkoxyamines were obtained from 4‐vinylbenzyl chloride and 4‐vinylbenzyl alcohol. The divinyl compound 1,2‐bis(4‐vinylphenyl)ethane was converted to an alkoxyamine monomer and to bisaminooxy compounds, which can be used as “biradical initiators” for NMRP.Formation of alkoxyamines using Mn(salen)Cl as the catalyst.magnified imageFormation of alkoxyamines using Mn(salen)Cl as the catalyst.

Chlorine‐functionalized TEMPO‐capped polystyrenes were investigated using the matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) technique. Amine‐ and acrylate‐functionalized agents and bifunctional TEMPO‐capped polystyrene were also analyzed to demonstrate the applicability of this method. Using this technique allowed to analyze the conversion of the chlorine function to an acrylate function, which was previously difficult to detect with other methods.MALDI‐TOF mass spectrum of a polystyrene described in this article, as obtained with DHB as the matrix.magnified imageMALDI‐TOF mass spectrum of a polystyrene described in this article, as obtained with DHB as the matrix.

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Summary: The bisaminooxy compounds Bis‐TEMPO and Bis‐TIPNO derived from 2,2,6,6‐tetramethyl‐piperidine‐1‐oxyl (TEMPO) and 2,2,5‐trimethyl‐4‐phenyl‐3‐azahexane‐3‐oxyl (TIPNO) were applied as “biradical initiators” for the nitroxide‐mediated radical polymerization (NMRP) of styrene and n‐butyl acrylate. It was shown by comparison with analogous alkoxyamines as unimolecular initiators and mixing experiments of mono‐ and biradical species, that in the case of the biradical initiators chain growth occurs at both sides under NMRP conditions. This enables a two‐step synthesis of A‐B‐A‐triblock copolymers. Kinetics and molecular mass development were investigated for the controlled biradical polymerization of styrene at different initiator concentrations, temperatures, and with addition of acetic anhydride as accelerator. For the controlled biradical polymerization of n‐butyl acrylate with Bis‐TIPNO, the effect of added free nitroxide relative to the initiator concentration was studied. The poly(styrene‐block‐n‐butyl acrylate‐block‐styrene) copolymers with higher block length prepared by this method show two glass transition temperatures, which indicates microphase separation of the polymer blocks.Structure of poly(styrene‐block‐n‐butyl acrylate‐block‐styrene), synthesized by nitroxide‐mediated radical polymerization with Bis‐TIPNO as initiator.imageStructure of poly(styrene‐block‐n‐butyl acrylate‐block‐styrene), synthesized by nitroxide‐mediated radical polymerization with Bis‐TIPNO as initiator.

SUMMARY: The influence of acrylonitrile during the grafting process of styrene onto pre-irradiated films of poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) and poly(tetrafluorothylene-alt-ethylene) (ETFE) was studied. The composition of the graft polymers was analysed with elementary analyses. A correlation between the acrylonitrile content of the monomer solution and the degree of grafting was determined.ZUSAMMENFASSUNG: Der Einfluß von Acrylnitril auf die Pfropfreaktion von Styrol auf Folien aus Poly-(tetrafluorethylen-co-hexafluorpropylen) (FEP) und Poly(tetrafluorethylen-alt-ethylen) (ETFE) wurde untersucht. Die Zusammensetzung der Pfropfcopolymeren konnte über Elementaranalyse bestimmt werden. Zwischen dem Acrylnitrilanteil in der Monomerlösung und der Massenzunahme der Folie konnte ein Zusammenhang ermittelt werden.

The use of a bisaminooxy compound as initiator for nitroxide‐mediated radical polymerization (NMRP) of styrene or n‐butyl acrylate allows the synthesis of α,ω‐nitroxide‐capped polymers. At high temperatures and with the addition of acetic anhydride, it was found that these polymers could be applied as macroinitiators in the free‐radical polymerization of methyl methacrylate. This enables the synthesis of block copolymers with only minor contents of homopolymer.The structure of bis‐TIPNO, the bisaminooxy compound used as an initiator for the nitroxide‐mediated radical polymerization of styrene or n‐butyl acrylate.magnified imageThe structure of bis‐TIPNO, the bisaminooxy compound used as an initiator for the nitroxide‐mediated radical polymerization of styrene or n‐butyl acrylate.

The influence of acrylonitrile during the grafting process of styrene onto pre‐irradiated films of poly(tetrafluoroethylene‐co‐hexafluoropropylene) (FEP) and poly(tetrafluorothylene‐alt‐ethylene) (ETFE) was studied. The composition of the graft polymers was analysed with elementary analyses. A correlation between the acrylonitrile content of the monomer solution and the degree of grafting was determined.