Method for radical polymerisation of thionolactides

A method for preparing at least one copolymer, preferably at least one degradable copolymer, said method comprising at least one step of radical polymerisation by ring opening of at least one cyclic monomer with at least one monomer comprising an ethylenic unsaturation, in the presence of a radical polymerisation initiator, wherein:

• (i) the cyclic monomer is selected from thionolactides of the following formula (I):
• wherein:
• X is an oxygen atom or a sulphur atom;
• R1, R2, R3, and R4, independently of each other, represent a hydrogen atom, a halogen atom, a group selected from an alkyl radical, a haloalkyl radical, an optionally substituted phenyl radical, a cyano group, an optionally substituted alkyl-phenyl radical, an optionally substituted haloalkyl-phenyl radical, a carboxylic acid radical, an ester radical CO2R5 with R5 representing an alkyl radical, a phosphonic acid radical, a phosphonic acid ester radical P(O)(OR6a)(OR6b) with R6a representing a hydrogen atom or an alkyl radical, and R6b representing an alkyl radical, a sulphonic acid radical, a sulphonic acid ester radical SO3R7 with R7 representing an alkyl radical or a haloalkyl radical, and an amide radical C(O)NR8aR8b, with Ra and R8b, independently of each other, representing a hydrogen atom or an alkyl radical, or together forming an alkyl radical;
• and
• (ii) the monomer including an ethylenic unsaturation is selected from monomers of the following formula (II):
• wherein:
• R9 represents a hydrogen atom or a fluorine atom;
• R10 represents a hydrogen atom or a fluorine atom;
• R11 represents a hydrogen atom, an alkyl radical, a fluorine atom or a chlorine atom;
• R12 represents a hydrogen atom, or a group selected from the following groups:
• an alkyl radical
• a haloalkyl radical
• an optionally substituted aryl radical,
• an optionally substituted alkyl-aryl radical,
• an imidazolyl group
• an alkylimidazolium group,
• a carbazoyl group, and
• a group of the following formula (III):
• wherein the asterisk (*) represents the anchor point of the group of formula (III) to the carbon atom of the compound of formula (II), and R3 and R14, identical or different, represent a hydrogen atom, an alkyl radical, an optionally substituted alkyl-aryl radical, an optionally substituted aryl radical, a glycidyl group, or R13 and R14, together with the nitrogen and carbon atoms of the group of formula (III) to which they are bonded, form a heterocarbon ring comprising from 4 to 7 carbon atoms,
• a —OC(O)R5 group, with R15 representing an alkyl radical, a haloalkyl radical, an optionally substituted alkyl-aryl radical, an optionally substituted aryl radical,
• a —C(O)OR16 group, with R16 representing an alkyl radical, a haloalkyl radical, an optionally substituted alkyl-aryl radical or an optionally substituted aryl radical,
• a phosphonic acid group,
• a phosphonic acid ester group P(O)(OR17a)(OR17b), with R17a representing a hydrogen atom or an alkyl radical, and R17b representing an alkyl radical,
• a sulphonic acid group,
• a sulphonic acid ester group SO3R18, with R18 representing an alkyl radical or a haloalkyl radical, and
• an amide group C(O)NR19aR19b with R19a and R19b, independently of each other, representing a hydrogen atom or an alkyl radical, or together forming an alkyl radical.

A copolymer, preferably a degradable copolymer, wherein said copolymer comprises at least thioester linkages, and said copolymer results from the radical polymerisation by ring opening:

• (i) of at least one cyclic monomer selected from thionolactides of the following formula (I):
• wherein:
• X is an oxygen atom or a sulphur atom;
• R1, R2, R3, and R4, independently of each other, represent a hydrogen atom, a halogen atom, a group selected from an alkyl radical, a haloalkyl radical, an optionally substituted phenyl radical, a cyano group, an optionally substituted alkyl-phenyl radical, an optionally substituted haloalkyl-phenyl radical, a carboxylic acid radical, an ester radical CO2R5 with R5 representing an alkyl radical, a phosphonic acid radical, a phosphonic acid ester radical P(O)(OR6a)(OR6b) with R6a representing a hydrogen atom or an alkyl radical, and R6b representing an alkyl radical, a sulphonic acid radical, a sulphonic acid ester radical SO3R7 with R7 representing an alkyl radical or a haloalkyl radical, and an amide radical C(O)NR8aR8b, with R8a and R8b, independently of each other, representing a hydrogen atom or an alkyl radical, or together forming an alkyl radical;
• and
• (ii) of at least one monomer including an ethylenic unsaturation selected from the monomers of the following formula (II):
• wherein:
• R9 represents a hydrogen atom or a fluorine atom;
• R10 represents a hydrogen atom or a fluorine atom;
• R11 represents a hydrogen atom, an alkyl radical, a fluorine atom or a chlorine atom;
• R12 represents a hydrogen atom, or a group selected from the following groups:
• an alkyl radical,
• a haloalkyl radical,
• an optionally substituted aryl radical,
• an optionally substituted alkyl-aryl radical,
• an imidazolyl group,
• an alkylimidazolium group,
• a carbazoyl group,
• a group of the following formula (III):
• wherein the asterisk (*) represents the anchor point of the group of formula (III) to the carbon atom of the compound of formula (II), and R13 and R14, identical or different, represent a hydrogen atom, an alkyl radical, an optionally substituted alkyl-aryl radical, an optionally substituted aryl radical, a glycidyl group, or R13 and R14, together with the nitrogen and carbon atoms of the group of formula (III) to which they are bonded, form a heterocarbon ring comprising from 4 to 7 carbon atoms (including the carbon atom carrying the oxygen atom),
• a —OC(O)R15 group, with R15 representing an alkyl radical, a haloalkyl radical, an optionally substituted alkyl-aryl radical, an optionally substituted aryl radical,
• a —C(O)OR16 group, with R16 representing an alkyl radical, a haloalkyl radical, an optionally substituted alkyl-aryl radical or an optionally substituted aryl radical, a phosphonic acid group,
• a phosphonic acid ester group P(O)(OR17a)(OR17b), with R17a representing a hydrogen atom or an alkyl radical, and R17b representing an alkyl radical,
• a sulphonic acid group,
• a sulphonic acid ester group SO3R18, with R18 representing an alkyl radical or a haloalkyl radical, and
• an amide group C(O)NR19aR19b, with R19a and R19b, independently of each other, representing a hydrogen atom or an alkyl radical, or together forming an alkyl radical, in the presence of a radical polymerisation initiator.