Synthesis of highly branched polymers via three-dimensional radical polymerization in the presence of oxygen

Abstract

It is shown that branched and highly branched vinyl polymers can be prepared by three-dimensional radical polymerization in the presence of dissolved oxygen, as exemplified by the oxidative copolymerization of styrene and divinylbenzene. The conditions of synthesis of highly branched polymers with a high yield—the ratio between monovinyl and divinyl comonomers and the rate of oxygen bubbling—are determined. The kinetics of formation of branched polystyrenes and the features of their molecular-mass distribution are studied. Elemental-analysis data show that the polymeric product contains 22–24 wt % oxygen, which, according to the IR data, enters into the composition of carbonyl, hydroxyl, and peroxide groups. The thermal decomposition of polymeric products is investigated via the TGA-DSC method. The main exothermal peak at ∼145°C is associated with the decomposition of peroxide groups, which is accompanied by the evolution of formaldehyde.