Novel group-transfer polymerization (GTP) of 4-methacryloyloxy-TEMPO for the preparation of poly(4-methacryloyloxy-TEMPO) (PTMA) has been developed. The new PTMA has been tested as an active electrode material in rechargeable organic radical battery (ORB). The advantage of the GTP method is that it affords PTMA containing the theoretical amount of nitroxide groups. Furthermore, cross-linked PTMA was prepared in the presence of small amounts of ethylene glycol dimethacrylate. Cyclic voltammetry of this PTMA showed a single, highly reversible redox couple at a potential of ca. 3.6 V (vs Li/Li+). This potential is similar to the potential of materials (e.g., LiCoO2) used for the positive electrode in lithium-ion batteries. In galvanostatic cycling experiments between 3.0 and 4.0 V in a half-cell setup vs metallic Li as counter and reference electrode a reversible specific charge of ca. 103 Ah kg-1 at current rates up to 1 C was obtained with the cross-linked PTMA. The useable charge capacity is very stable with cycling, showing only a slight decrease after 200 full charge−discharge cycles at 2 C.

The position of radical polymerization (RP) in the context of polymer industry is highlighted. The mechanistic steps of RP are discussed from an industrial point of view. An overview of industrial initiators including photoinitiators, chain transfer agents, and monomer stabilizers is given. The most important polymerization processes with focus on emulsion polymerization (EP) and dispersion polymers as well as types of polymerization reactors are presented. The progress of controlled RP toward commercialization is reviewed.

Alkoxyamines and persistent nitroxyl radicals are important regulators of nitroxide mediated radical polymerization (NMP). Because polymerization times decrease with increasing rate constant of the homolysis of the C-ON bond between the polymer chain and the nitroxyl moiety, the factors influencing the cleavage rate constant are of considerable interest. Here, we present the measurements of the rate constants (k d) of the C-ON bond cleavage in new cyclic alkoxyamine models. The homolysis rate constants of 9 new alkoxyamines and 33 others given by the literature are analyzed with regards to the contributions of the polar inductive/field (σ I) effect, the steric (Es) effect and the intramolecular hydrogen bonding (IHB) effect of the nitroxyl moieties, using the multiparameter equation established by Marque, i.e., log(k d/kd,0) ) -3.07σI -0.88Es -5.88. Cyclic steric constants r(Ri) for seven-and eightmembered rings are developed. Analysis of the results provides new insight on the importance of the conformation of the alkoxyamine on the values of k d.

A straightforward synthesis of a novel spirobisnitroxide 6 has been developed. Cyclovoltammetry of 6 revealed two distinct reversible oxidation/reduction steps separated by ca. 740 mV indicating the formation of the corresponding oxoammonium cations. Rhodium-catalyzed polymerization of 6 afforded the polyacetylene polymer 7 bearing the pending spirobisnitroxide groups. Additionally, cross-linked 7 was prepared in the presence of 3 mol % of N,N′-diprop-2-ynyl-oxalamide. If oxidation of both nitroxide groups is considered, 7 possesses an unprecedented high theoretical charge capacity of 174 mA h g−1. Evaluation of the cross-linked polymer 7 as a cathode material for an organic radical battery showed very good cycling stability when the potential was kept below the oxidation potential of the five-membered nitroxide subunit of 6. A presumable irreversible degradation of the polymeric backbone of 7 occurred at higher potentials, limiting the experimentally obtained charge capacity to 73 mA h g−1.