Hypervalent iodine‐based initiators and efficient chain transfer agents for the synthesis of branched polymers from crosslinkers

Abstract

The synthesis of hyperbranched polymers with alkyl chloride-type chain ends was accomplished by the copolymerization of methyl methacrylate and a crosslinker, ethylene glycol dimethacrylate, in the presence of 1-chloro-1,2-benziodoxol-3(1H)one (BIO-Cl), which served as both a radical initiator and an efficient chain transfer agent. The polymerizations were carried out under thermal (80 °C) and photochemical (irradiation with visible light) conditions. As a result of the transfer of Cl atoms from BIO-Cl to the propagating radicals, gelation was delayed to high monomer conversions and, until that point, soluble branched polymers were formed. Even pure crosslinker could be polymerized to moderate conversions (>15%, depending on the amount of added BIO-Cl), yielding branched polymers prior to formation of networks. The effect of the concentrations of crosslinker and hypervalent iodine(III) compound on the outcome of the (co)polymerizations as well as the kinetic features of Cl transfer and decomposition of BIO-Cl were studied in detail.

Special Issue: Functional Polymers and Composites: From Synthesis to Applications (Dedicated to the 80th Anniversary of Professor George S. Georgiev)

“…As mentioned, Professor Georgiev has made major contributions to the field of modeling (co)polymerization reactions. The next paper, in which fundamental/mechanistic studies are combined with the development of synthetic methodologies, is contributed by Tsarevsky et al 20 It is related to work carried out by Georgiev and his research team (and started in the 1990s in Greece) on hypervalent iodine‐containing initiators of polymerization. Subsequent papers present synthetic approaches, some of which are based on controlled (reversible deactivation) radical polymerization.…”