Method for preparing a polymeric material including a multiblock copolymer prepared by controlled free-radical polymerisation

A method for preparing a polymeric material comprising a copolymer comprising at least one block A and at least one block B, said method comprising successively:

• a) a step of polymerizing one or more free-radical-polymerizable monomers by controlled free-radical polymerization, so as to form block A;
• b) a step of polymerizing the monomers that were not converted during step a), so as to form a polymer of chemical nature identical to block A but having a number-average molecular weight lower than that of block A;
• c) a step of adding to the medium resulting from steps a) and b) one or more free-radical-polymerizable monomers that are precursors of block B;
• d) a step of polymerizing said monomers that are precursors of block B by controlled free-radical polymerization, said block B being linked to block A by covalent bonding;
• and
• e) optionally, a step of polymerizing the monomers that were not converted during step d), so as to form a polymer of chemical nature identical to block B but having a number-average molecular weight lower than that of block B.