Vinylarenetricarbonyl complexes of chromium as chain propagation regulators for polymerization of acrylic monomers

Abstract

The polymerization of methyl methacrylate and butyl acrylate initiated by azo-bis-isobutyronitrile in the presence of metal-containing monomers (p-methylstyrene-, stilbene-and α-methylstyrenechromiumtricarbonyl) was studied. Kinetic parameters (i.e. the decrease in the autoacceleration during the polymerization of acrylic monomers, its shift towards a high conversion region in the presence of α-methylstyrenechromiumtricarbonyl, a linear dependence of the molecular weight of a polymethyl methacrylate and the shift of molecular-weight distribution curves to a high molecular weight region with conversion) demonstrate the influence of vinylarenetricarbonyl complexes of chromium on basic steps of polymerization. It is important to note that the above organometallic compounds enable the controlled synthesis of polymers under temperature conditions (50-70 • C) corresponding to those of the industrial polymer production.

Diphenylbutadiene chromium tricarbonyl in radical polymerization of methylmethacrylate

“…This process can proceed simultaneously with 'living' polymerization and is observed, for example, during controlled radical polymerization in the presence of triphenylmethyl 18 and some other sterically hindered carbon-centered radicals, including organometallic ones. 6,7 Thus, the data obtained indicate that DPC is a novel, specific chain propagation regulator for the radical polymerization of MMA at temperatures approaching the optimal conditions of industrial synthesis of polymers.…”

“…without autoacceleration and with the synthesis of polymers of the desired molecular weight characteristics. 1,2 Stable radicals and their sources, 3,4 including organometallic additives, 5,6 have been actively employed recently in chain propagation regulators in radical initiation. In particular, α-methylstyrene chromium tricarbonyl and allylbenzene chromium tricarbonyl were reported to influence chain propagation in the polymerization of methylmethacrylate (MMA), styrene and butyl acrylate.…”

“…In particular, α-methylstyrene chromium tricarbonyl and allylbenzene chromium tricarbonyl were reported to influence chain propagation in the polymerization of methylmethacrylate (MMA), styrene and butyl acrylate. 6,7 A regulating effect of the organochromium additives is caused by their action with both, the radicals derived from an initiator and the growing macroradicals to form relatively stable carboncentered metal-containing radicals that influence the rate of polymerization and molecular weight of the polymers prepared. 5 -8 In this paper, the kinetic parameters of MMA polymerization and the molecular weight characteristics of the polymers obtained in the presence of diphenylbutadiene chromium tricarbonyl (DPC) are discussed.…”

(Allylbenzene)tricarbonylchromium in Radical Polymerization of Methyl Methacrylate and Styrene

“…Nitroxyl radicals and their sources [3,4] and organometallic compounds [2,4], including metalcontaining monomers [5,6], are actively used today to control the chain propagation in radical polymerization processes. In particular, (a-methylstyrene)tricarbonylchromium affects the propagation step in polymerization of methyl methacrylate (MMA), styrene (ST), and butyl acrylate [6].…”

“…In particular, (a-methylstyrene)tricarbonylchromium affects the propagation step in polymerization of methyl methacrylate (MMA), styrene (ST), and butyl acrylate [6]. The controlling effect of organochromium additives is due to their reaction with initiator radicals and propagating macroradicals to form relatively stable carbon-centered organometallic radicals directly affecting the polymerization rate and molecular weight of the polymers [5,6].…”