Three-dimensional free-radical polymerization of vinyl monomers in the presence of oxygen as a new method of preparing hyperbranched polymers: A theoretical calculation

Hyperbranched macromolecules have been first synthesized by the three-dimensional free-radical polymerization of vinyl monomers in the presence of oxygen, which is known to be a strong inhibitor of freeradical chain processes. The inhibition of free-radical polymerization by molecular oxygen results in the shortening of primary polymer chains with pendant double bonds. As a consequence, the formation of insoluble gel, which develops at conversions of less than 1%, when the crosslinking free-radical polymerization is carried out under ordinary conditions, may be avoided up to a conversion of 100%. In terms of the kinetic scheme, including nearly 100 elementary reactions, the effects of temperature and concentration of reagents on the kinetic parameters of the process and the structural parameters of hyperbranched polymers based on methacrylate and styrene-like monomers have been studied. Optimal conditions that make it possible to synthesize hyperbranched polymers of the desired architecture and functionality at a sufficiently high yield, which are specified by the occurrence of oxygen-containing groups in primary polymer chains and at its ends, have been estimated.