ABSTRACT
The kinetic modeling of styrene controlled radical polymerization, initiated by 2,2’-asobis(isobutirnitrile) and proceeding by a reversible chain transfer mechanism was carried out and accompanied by “addition-fragmentation” in the presence dibenzyltritiocarbonate. An inverse problem of determination of the unknown temperature dependences of single elementary reaction rate constants of kinetic scheme was solved. The adequacy of the model was revealed by comparison of theoretical and experimental values of polystyrene molecular-mass properties. The influence of process controlling factors on polystyrene molecular-mass properties was studied using the model
The controlled radical polymerization is one of the most developing synthesis methods of narrowly dispersed polymers nowadays [1-3]. Most considerations were given to researches on controlled radical polymerization, proceeding by a reversible chain transfer mechanism and accompanied by “addition-fragmentation” (RAFT – reversible addition-fragmentation chain transfer) [3]. It should be noted that for classical RAFT-polymerization (proceeding in the presence of sulphur-containing compounds, which formula is Z-C(=S)–S-R’, where Z – stabilizing group, R’ – outgoing group), valuable progress was obtained in the field of synthesis of new controlling agents (RAFT-agents), as well as in the field of research of kinetics and mathematical modeling; and for RAFT-polymerization in symmetrical RAFT-agents’ presence, particularly, tritiocarbonates of formula R’– S-C(=S)–S-R’, it came to naught in practice: kinetics was studied in extremely general form [4] and mathematical modeling of process hasn’t been carried out at all. Thus, the aim of this research is the kinetic modeling of polystyrene controlled radical polymerization initiated by 2,2’-asobis(isobutirnitrile) (AIBN), proceeding by reversible chain transfer mechanism and accompanied by “addition-fragmentation” in the presence of dibenzyltritiocarbonate (DBTC), and also the research of influence of the controlling factors (temperature, initial concentrations of monomer, AIBN and DBTC) on molecular-mass properties of polymer.
