The free-radical bulk homopolymerization of styrene and n-butyl acrylate at 80°C mediated by dibenzyl trithiocarbonate, poly(styryl) trithiocarbonate, or poly(n-butyl acrylate) trithiocarbonate as reversible addition-fragmentation chain-transfer agents has been studied. It has been shown that the use of low-and high-molecular-mass reversible addition-fragmentation chain-transfer agents makes it possible to efficiently control the molecular-mass characteristics of polymers. In the case of styrene, the rate of polymerization slightly depends on the concentration of the addition-fragmentation chain-transfer agent. In contrast, for the polymerization of n-butyl acrylate, the rate significantly decreases with the concentration of the chain-transfer agent. Formation of radical intermediates during the polymerization of styrene and n-butyl acrylate mediated by trithiocarbonates has been studied by ESR spectroscopy. It has been demonstrated that the polymeric chain-transfer agents are efficient for the synthesis of block copolymers with the controlled block length.

Modern approaches to the synthesis of tailor-made macromolecules by radical polymerization proceeding through the reversible addition-fragmentation chain-transfer mechanism are considered. The mechanism of this process and the experimental and calculation methods for determining its main kinetic parameters are discussed. Particular emphasis is placed on the problems of designing copolymers of various microstructures, including random, gradient, and block copolymers.

Spin traps have been used to obtain the first direct experimental determination of the addition (5 × 10⁶ L mol⁻¹ s⁻¹), fragmentation (8 × 10⁻³ s⁻¹) and self-termination (6.5 × 10² L mol⁻¹ s⁻¹) rate coefficients in RAFT polymerization using the interaction of a tert-butyl radical with tert-butyl dithiobenzoate at ambient temperature as a model reaction.

The radical polymerization of styrene at 60 and 80°C mediated by benzyl dithiobenzoate and poly(styrene dithiobenzoate) as reversible addition-fragmentation chain-transfer agents has been studied. It has been shown that both agents are characterized by high chain-transfer constants and provide control over molecular-mass characteristics of polymerization products. The number-average molecular mass of polystyrene linearly grows with conversion, and the polymers are characterized by low values of polydispersity indexes. It has been demonstrated that the rate of polymerization significantly decreases with an increase in the concentration of reversible addition-fragmentation chain-transfer agents. This effect is typical of styrene polymerization mediated by dithiobenzoates. The possible reasons for this phenomenon are discussed.

The relative monomer reactivities in the reversible addition–fragmentation chain transfer (RAFT) radical copolymerization of styrene (S) and acrylic acid (AA) in a solution of the polar solvent N,N-dimethylformamide are found to be dependent on the chemical nature of the RAFT agent. Polymeric RAFT agents based on polyacrylic acid enhance the difference in monomer reactivities (dithiobenzoate – r_AA = 0.09 ± 0.02, r_S = 3.5 ± 1.2, trithiocarbonate – r_AA = 0.08 ± 0.04, r_S = 3.03 ± 1.78) compared to low molecular weight RAFT agents (dibenzyl dithiobenzoate – r_AA = 0.14 ± 0.01, r_S = 1.00 ± 0.01, dibenzyl trithiocarbonate – r_AA = 0.08 ± 0.01, r_S = 0.85 ± 0.03). The opposite effect on the relative reactivity of acrylic acid is observed when polymeric RAFT agents based on polystyrene are used (dithiobenzoate – r_AA = 3.3 ± 0.4, r_S = 0.72 ± 0.05, trithiocarbonate – r_AA = 0.11 ± 0.01, r_S = 0.54 ± 0.03). In all the investigated systems the copolymers formed are characterized by narrow MWD due to the high efficiency of the chosen RAFT agents.

The polymerization of acrylonitrile mediated by various trithiocarbonates as reversible addition-fragmentation chain-transfer agents is studied. It is shown that, when polymerization is performed in DMSO, a narrowly dispersed PAN with a controlled molecular mass can be prepared. The pseudoliving radical polymerization of acrylonitrile is conducted for the first time via the reversible addition-fragmentation chaintransfer mechanism in carbon dioxide at an increased pressure. The structure of the polymers is investigated via NMR and IR spectroscopy. As shown by DSC and IR pyrolysis, the thermal behavior of PAN is determined by its molecular mass, the width of the molecular-mass distribution, and the conditions of synthesis. The incorporation of functional groups of the reversible addition-fragmentation chain-transfer agent into a macromolecule changes the structure of the polyconjugated system and makes it possible to control the conditions of its formation.