The catalytic system tri-n-butyl boron-p-quinone in the free-radical polymerization of styrene

Synthesis of Copolymers of Methyl Methacrylate and Butyl Vinyl Ether in the Presence of the System Tributylboron – 2,5-di-tert-butyl-p-benzoquinone

“…Chemical shifts are presented in the delta scale (δ, ppm) in relation to Me 4 Si. The content of poly(butyl vinyl ether) (PBVE) in its copolymer with PMMA was calculated according to the formula:…”

“…The direction of reaction (1) is determined by the structure of a monomer and p-quinone [2][3][4][5]. Thus, polystyrene propagation radicals are added to the p-quinone molecule only at the C=O bond (Scheme 1, direction 1) [2], independently of its structure.…”

“…The macromolecules that are formed in compliance with Scheme 2, are macroinitiators, they are instrumental in re-initiation of the polymerization according to the reversible inhibition mechanism (Sheme 4) [4,8]:…”

Tri-n-butylboron-p-quinone catalytic system in synthesis of block copolymers

“…The main advantage of this approach is control of the molecular weight and composition of the forming macromolecules. One of the ways to implement this approach is the use of the tri-n-butylboron-p-quinone catalytic system [3][4][5][6]. The use of this system allows polymerization of some vinyl monomers to be performed in controlled mode (Scheme 1).…”

“…It has been found that addition of a macroradical to the C=O bond of p-quinone, followed by radical substitution at the boron atom, yields adduct I (macroinitiator), which is capable of reversible homolytic dissociation across the С-О bond [reaction (2)], ensuring the occurrence of the polymerization in the pseudoliving mode [4][5][6][7]. In polymerization of methyl methacrylate (MMA) [3], methyl acrylate, and vinyl acetate in the Scheme 1.…”