Thermoassociative and exchangeable copolymers, and composition comprising same

1. A comb copolymer A2 comprising at least two boronic ester functional groups,

said copolymer comprising a main chain and side chains, at least a portion of the side chains of the copolymer A2 being composed of oligomers comprising more than 30 carbon atoms.

2. The comb copolymer A2 as claimed in claim 1 , in which at least a portion of the side chains are composed of oligomers comprising at least 50 carbon atoms.

3. The comb copolymer A2 as claimed in claim 1 , in which at least a portion of the side chains of the copolymer A2 are composed of oligomers which exhibit a degree of polymerization ranging from 5 to 1000.

4. The comb copolymer A2 as claimed in claim 1 , in which the side chains composed of oligomers comprising more than 30 carbon atoms represent from 3% to 95% by weight, with respect to the total weight of the copolymer A2.

5. The comb copolymer A2 as claimed in claim 1 , in which at least a portion of the side chains of the copolymer A2 are composed of oligomers O1 comprising a polyolefin fragment.

6. The comb copolymer A2 as claimed in claim 5 , in which the side chains composed of oligomers O1 comprise a polyolefin fragment having from 30 to 500 carbon atoms.

7. The comb copolymer A2 as claimed in claim 5 , in which the side chains comprising a polyolefin fragment represent from 3% to 85% by weight, with respect to the total weight of the copolymer A2.

8. The comb copolymer A2 as claimed in claim 5 , in which the oligomers O1 are present in the copolymer A2 in the form of repeat units corresponding to one or more monomers M6 of general formula (IX):

in which:

Q 1 is chosen from the group consisting of —H, —CH 3 and —CH 2 —CH 3 ;

Q 2 is chosen from the group consisting of -Q′, −O-Q′, —C(O)—O-Q′, −O—C(O)-Q′, —S—(CH 2 ) 2 —C(O)—O-Q′, —S-Q′, —N(H)—C(O)-Q′ and —C(O)—N(H)-Q′ group, with Q′ is a polyolefin,

n represents an integer chosen from 0 and 1,

A represents a divalent group chosen from the group consisting of -A 1 -, —O-(-A 2 -O-) n′ -A 1 -, —C(O)—O—(-A 2 -O-) n′ -A 1 -, −O-C(O)-(-A 2 -O-) n′ -A 1 -, —S—(-A 2 -O-) n′ -A 1 -, —N(H)—C(O)—(-A 2 -O-) n′ -A 1 and —C(O)—N(H)-(-A 2 -O-) n′ -A 1 - with:

A 1 is a divalent group chosen from the group consisting of a C 1 -C 30 alkyl, a C 6 -C 30 aryl and a C 6 -C 30 aralkyl,

A 2 is a divalent group chosen from C 2 -C 4 alkyls,

n′ is an integer, n′ represents 0 or 1.

9. The comb copolymer A2 as claimed in claim 1 , comprising at least repeat units corresponding to monomers M4 of formula (IV):

in which:

t is an integer equal to 0 or 1;

u is an integer equal to 0 or 1;

M and R 8 are divalent linking groups, which are identical or different, chosen from the group consisting of a C 6 -C 18 aryl, a C 7 -C 24 aralkyl and a C 2 -C 24 alkyl;

X is a functional group chosen from the group consisting of —O—C(O)—, —C(O)—O—, —C(O)—N(H)—, —N(H)—C(O)—, —S—, —N(H)—, —N(R′ 4 )— and −O—, with R′ 4 a hydrocarbon chain comprising from 1 to 15 carbon atoms;

R 9 is chosen from the group consisting of —H, —CH 3 and —CH 2 —CH 3 ;

R 10 and R 11 , which are identical or different, represent a group chosen from the group consisting of a hydrogen atom and a hydrocarbon group comprising from 1 to 30 carbon atoms, optionally substituted by one or more groups chosen from: a hydroxyl or an —OJ or —C(O)—O-J group, with J a hydrocarbon group comprising from 1 to 24 carbon atoms.

10. The comb copolymer A2 as claimed in claim 9 , in which the repeat units corresponding to monomers M4 represent from 1 mol % to 50 mol %, with respect to the total number of moles of the monomers of which the copolymer A2 is composed.

11. The comb copolymer A2 as claimed in claim 1 , comprising at least repeat units corresponding to monomers M5 of general formula (V):

in which:

R 12 is chosen from the group consisting of —H, —CH 3 and —CH 2 —CH 3 ,

R 13 is chosen from the group consisting of a C 6 -C 18 aryl and a C 6 -C 18 aryl substituted by a R′ 13 , —C(O)—O—R′ 13 , —O—R′ 13 , —S—R′ 13 and —C(O)—N(H)—R′ 13 group, with R′ 13 a C 1 -C 30 alkyl group.

12. The comb copolymer A2 as claimed in claim 11 , in which the repeat units corresponding to monomers M5 represent from 10 mol % to 90 mol % with respect to the total number of moles of the monomers of which the copolymer A2 is composed.

13. The comb copolymer A2 as claimed in claim 1 , which comprises repeat units corresponding to at least one monomer M3 of general formula (X):

in which:

Z 1 , Z 2 and Z 3 , which are identical or different, represent groups chosen from the group consisting of a hydrogen atom, a C 1 -C 12 alkyl or an —OZ′ and —C(O)—O—Z′ group, with Z′ a C 1 -C 12 alkyl.

14. The comb copolymer A2 as claimed in claim 13 , in which the monomer M3 is styrene.

15. The comb copolymer A2 as claimed in claim 13 , in which the repeat units corresponding to monomers of formula (X) represent from 2 mol % to 50 mol %, with respect to the total number of moles of the monomers of which the copolymer A2 is composed.

16. The comb copolymer A2 as claimed in claim 1 , in which the copolymer A2 exhibits a degree of branching ranging from 0.1 mol % to 10 mol %.

17. The comb copolymer A2 as claimed in claim 1 , in which the main chain of the comb copolymer A2 has a number-average degree of polymerization ranging from 40 to 2000.

18. A composition resulting from the mixing of at least:

a polydiol compound A1,

a copolymer A2 as claimed in claim 16 .

19. The composition as claimed in claim 18 , in which the polydiol compound A1 is a copolymer resulting from the copolymerization:

of at least one first monomer M1 of general formula (I):

in which:

R 1 is chosen from the group consisting of —H, —CH 3 and —CH 2 —CH 3 ;

y is an integer equal to 0 or 1;

Y represents a divalent linking group chosen from C 1 -C 20 alkyl chains, optionally comprising one or more ether —O— bridges;

X 1 and X 2 , which are identical or different, are chosen from the group consisting of hydrogen, tetrahydropyranyl, methyloxymethyl, tert-butyl, benzyl, trimethylsilyl and t-butyldimethylsilyl;

or else

X 1 and X 2 form, with the oxygen atoms, a bridge of following formula:

in which:

the stars (*) symbolize the bonds to the oxygen atoms,

R′ 2 and R″ 2 , which are identical or different, are chosen from the group consisting of hydrogen and a C 1 -C 11 alkyl group;

or else

X 1 and X 2 form, with the oxygen atoms, a boronic ester of following formula:

in which:

the stars (*) symbolize the bonds to the oxygen atoms,

R′″ 2 is chosen from the group consisting of a C 6 -C 30 aryl, a C 7 -C 30 aralkyl and a C 2 -C 30 alkyl;

with at least one second monomer M2 of general formula (II):

in which:

R 2 is chosen from the group consisting of —H, —CH 3 and —CH 2 —CH 3 ,

R 3 is chosen from the group consisting of —C(O)—O—R′ 3 ; —O—R′ 3 ; —S—R′ 3 and —C(O)—N(H)—R′ 3 , with R′ 3 a C 1 -C 30 alkyl group.

20. A lubricating composition resulting from the mixing of at least:

a lubricating oil; and

a composition as claimed in claim 18 .