METHOD FOR PREPARING BLOCK-COPOLYMERS Russian patent published in 2008 - IPC C08F293/00 C08F4/04 C08F2/06 

FIELD: chemistry of polymers, chemical technology.

SUBSTANCE: invention relates to a method for synthesis of block-copolymers based on vinylaromatic monomers and monomers representing derivatives of (meth)acrylic acid. Invention describes a method for synthesis of block-copolymers by means of radical polymerization involving the following steps: (a) polymerization of vinylaromatic monomer at temperature 120°C or above in the presence of the radical-initiating system consisting of a compound of the general formula (I) given in the invention description and wherein R₁ and R₂ are similar or different and represent methyl or ethyl radical; X₁ represents hydrogen atom; X₂ represents hydrogen atom or hydroxyl, or X₁ and X₂, similar or different, represent (C₁-C₄)-(iso)alkyl radicals, or they form in common aromatic ring; n = 0 or 1; R₃ represents radical chosen from one of the following groups: -C(CH₃)₂-CN, -CHCH₃-Ph, or R₃ is absent as unpaired electron occupies its place, and used in mixture with compounds (G) generating radicals chosen from peroxides, peracid esters, percarbonates, azobisdialkyldinitriles in the molar ratio (I)/(G) less 4 up to the conversion degree of monomer from 5 to 99.9%; (b) feeding a monomer representing a derivative of (meth)acrylic acid to polymerization mixture from step (a) after the necessary conversion degree in the amount providing the total mass of block-copolymer M_w is less 500000 Da, and this step is carried out at the same temperature and in the presence of the same initiating system; (c) isolation of synthesized block-copolymer after termination of the polymerization reaction. Also, invention describes a block-copolymer. Invention provides synthesis of block-copolymer comprising the decreased amount of homopolymer and statistic copolymer, elimination of the precipitation step and isolation of the first polymeric block.

EFFECT: improved method of synthesis.

11 cl, 11 ex