Method for synthesis of block polymers by controlled free radical polymerization

A process for preparing a second generation block copolymer by free radical polymerization, comprising the step of carrying out a free radical polymerization on a composition comprising:

• an ethylenically unsaturated monomer of formula CYY′(CW═CW′)n═CH2,
• a first generation polymer of general formula (II):
• wherein:
• R1 represent:
• an optionally substituted alkyl, acyl, aryl, aralkyl, alkene or alkyne group,
• an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring,
• a polymeric chain,
• R2 and R3, which are identical or different, represent:
• a hydrogen atom,
• —S—R1 or —S—[CXX′—(CV═CV′)b—CH2]n—R1,
• an optionally substituted alkyl, acyl, aryl, aralkyl, alkene or alkyne radical,
• an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring,
• R2 and R3, together, represent the atoms needed to form an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring,
• n and m, which are identical or different, are greater than or equal to 1,
• V, V′, W and W′, which are identical or different, represent:
• H, an alkyl group or a halogen,
• X, X′, Y and Y′, which are identical or different, represent H, a halogen or a group R4, OR4, O2COR4, NHCOH, OH, NH2, NHR4, N(R4)2, (R4)2N+O−, NHCOR4, CO2H, CO2R4, CN, CONH2, CONHR4 or CON(R4)2, in which R4 is selected from alkyl, aryl, aralkyl, alkaryl, alkene or organosilyl groups which are optionally perfluorinated and optionally substituted by one or more carboxy, epoxy, hydroxyl, alkoxy, amino, halogen or sulfonic groups, and
• a and b, which are identical or different, are 0 or 1,
• the second generation block copolymer being of formula (I):
• wherein R1, R2, R3, X, X′, W, W′, V and V″ have the meaning given above.

A process for preparing a first generation polymer, comprising the step of free radical polymerization of a composition comprising:

• at least one ethylenically unsaturated monomer,
• a source of free radicals, and
• at least one compound (III) of general formula (IIIA), (IIIB) or (IIIC):
• wherein:
• R1 and R′1 represent:
• an optionally substituted alkyl, acyl, aryl, aralkyl or alkyne group,
• an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring,
• a polymeric chain,
• R2, R3 and R′2, which are identical or different, represent:
• a hydrogen atom,
• —S—R1,
• an optionally substituted alkyl, acyl, aryl, aralkyl, alkene or alkyne radical,
• an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring,
• R2 and R3, or R′2 and R3, together, represent the atoms needed to form an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring, and
• p is between 2 and 10.

A process for preparing an Nth generation block copolymer by free radical polymerization, N being greater than or equal to 2, said process comprising:

• a first step of free radical polymerization to form a first generation polymer starting from a composition comprising:
• at least one ethylenically unsaturated monomer,
• a source of free radicals, and
• at least one compound (III) of general formula (IIIA), (IIIB) or (IIIC):
• wherein:
• R1 and R′1 represent:
• an optionally substituted alkyl, acyl, aryl, aralkyl or alkyne group,
• an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring,
• a polymeric chain,
• R2, R3 and R′2, which are identical or different, represent:
• a hydrogen atom,
• —S—R1,
• an optionally substituted alkyl, acyl, aryl, aralkyl, alkene or alkyne radical,
• an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring,
• R2 and R3, or R′2 and R3, together, represent the atoms needed to form an optionally substituted, aromatic, saturated or unsaturated heterocyclic or carbon ring, and
• p is between 2 and 10, followed by N-1 steps of free radical polymerization, each of these steps being implemented starting from a composition comprising:
• at least one ethylenically unsaturated monomer,
• a source of free radicals, and
• the block polymer obtained in the preceding step of polymerization, the ethylenically unsaturated monomer or monomers being such that the block formed in this step is different in nature to the block formed in the preceding step.